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Station Grounding

Steve Katz (WB2WIK) on August 17, 2004
View comments about this article!


STATION GROUNDING

Will we ever be able to dispel the myths?

Steve Katz, WB2WIK/6

This is a much beaten-up subject. Hardly a day goes by that on some ham radio board or reflector there isn't a question about “station grounding.” Funny part is, the subject's been so discussed, that anyone asking a question must have not been paying attention for the past several (fill in: days, weeks, months, years).

Problem

I think the biggest problem is that a lot of commercially manufactured equipment comes complete with a “ground terminal,” usually somewhere on the rear of its chassis. That, along with directions from the equipment manufacturers, implies the equipment owner ought to connect something to it.

I view this as an adjunct to the “SWR” dilemma. You know, the one that drives hams crazy believing that for an antenna to work properly it must have a low SWR. Or, sillier still, that an antenna with a low SWR must be working properly.

It's funny that before about 1960, few hams owned an SWR measuring instrument of any sort but somehow made DXCC, bounced signals off the moon, worked meteor scatter, aurora and E-skip, and just happily made contacts without having the foggiest idea what their antenna's SWR was. Commercial transmitters didn't have internal SWR bridges, and inexpensive bridges weren't on the market. The famous “Monimatch” circuit hadn't yet been published, so few hams knew how to build an SWR bridge, nor would they bother trying. Hams, and their transmitters, were perfectly content to be working each other, around the world, without this fabulous knowledge.

Now, back then it was also pretty common for a lot of equipment to not even have a ground terminal. Some of it did, some of it didn't, and it didn't matter much one way or the other. I think the best reason for a ground terminal would have been to help prevent equipment users from killing themselves due to internal short-circuits in equipment that was AC powered, back before 3-prong (and 3-wire) power cords, plugs and outlets became common.

Ironically, the most unsafe equipment back in those days was thousands - if not millions - of inexpensive, AC-line powered broadcast radios, including bedside “All American Five” type radios and clock radios, which did not use AC line isolation transformers. To minimize production cost, a lot of these radios directly rectified the AC line and fed a full 120 volts AC to a series string of tube filaments. The string totaled around 120 volts, so no filament transformer was needed. One side of the AC mains was connected directly to the radio chassis (preferably, the “cold” side of the mains!), and to prevent people from touching the chassis, the little radios were installed in plastic enclosures and used plastic knobs over the control shafts. These radios did not have 3-wire power cords.

Those were accidents waiting to happen, of course. Untold thousands of people received electrical shocks from these radios, and they were responsible for more than a few fires. Sadly, some probably lost their lives due to such shabby design.

And while those radios really indicated an actual need for a chassis (earth, safety) ground, they didn't have any provision for one.

But we don't use radios like that any more. Now, we have equipment that uses isolation transformers, and 3-wire power cords plugged into grounded outlets. And a lot of our equipment is powered by low voltage DC, where a shock hazard is literally nonexistent. (You can be hurt by low voltage DC, but not electrocuted. The major source of injuries to people working with low voltage DC is in the form of burns caused by jewelry shorting out the DC power supply's output bus, which can often pump dozens of Amperes through a ring or bracelet before shutting down - if it ever shuts down.)

So, why do we ground?

Really good question. I guess I'd preface my answer with this simple statement:

I've been a licensed ham for 39 years, and continually active. I run legal-limit amplifiers and power output on 160 meters through 10 meters, a kilowatt on 6 and 2 meters, and a couple hundred watts on 135cm and 70cm, and sometimes on 33cm and 23cm, too. I've used dozens of different antenna configurations and have operated from all over the world, but mostly from any of the fifteen home-station hamshacks I've built over the years at the various homes I've owned.

And in all that time, I've never once had a “station ground” of any sort.

And in all that time, I've never had any problem that grounding would solve.

I've operated mobile, marine mobile, maritime mobile and aeronautical mobile and never had a ground on any of these vehicles, either. Especially when operating from an aircraft, that's hard to do. I've also set up dozens of field operations, including Field Day and other contests, without ever owning a ground rod or feeling the need to drive one in, anywhere.

Therefore, you can see I'd be a tough one to convince that a “station ground” serves any particular purpose. Not to say it cannot help, in some situations. But in most all those situations, better station engineering would help more.

(For clarification: Nowhere in this article will I say it's a bad thing to ground your equipment. I just discuss the counterpoint, that grounding your equipment usually isn't necessary, and if you're spending any time deliberating on this issue, that's time wasted that you could be operating, instead.)

RF grounding

There's surely such a thing, and it's a good thing. If I ever use a voltage-fed antenna or a random wire, I usually place my antenna tuner outdoors, or at least in an open window, so the entire antenna is literally outside, and then I have a very short and direct path to Mother Earth for the return current. The earth completes the current path from transmitter to antenna and back, and everything is happy. This is a great situation. But you really need to have the tuner laying on the ground, or very darned close to it, to accomplish this feat - because a tuner sitting on a desk in the shack is often too far from ground to be effectively grounded.

Usually, however, I use current-fed antennas and I match the antennas to their transmission lines (by adjusting the antennas themselves). Most of my lines are coaxial cable, but some are twin lead. If I use coax to feed a balanced antenna, I use a current balun at the antenna feedpoint. If I use twin lead to feed a balanced antenna, I don't need a balun, except perhaps in the shack where I transition to 50 Ohm equipment. In all cases, the lines are cool and quiet and don't seem to bring any RF back “down the pipe” from antenna into the shack.

That's the result of matching, choking and cable routing to minimize this problem. That not only works better than grounding the station equipment, but it's also easier to accomplish, usually.

It's true that most antenna designs won't provide a good match over more than maybe 2% of the operating frequency. So what? My 80 meter inverted vee is resonant at 3.750 MHz, and its SWR rises to >3:1 at both band edges (upper and lower). Yep, that's about 25% reflected power. Okay, I'll repeat: So what? I use my amplifiers as antenna tuners, can transfer all the power generated to the load just fine, and have zero RFI, RF “feedback,” or other problems. No “hot mikes,” no burns from accessories, no nothing, nada, zip. The secret is station engineering. That is, my antennas are located sufficiently far from my equipment that very little radiates back into places I don't want it to be. And, I do use current baluns in the form of coaxial RF chokes and the like; and, for stubborn cases (especially on the very lower frequency bands, where it's difficult to escape the antenna's near field) I use ferrite isolators on the feedlines, installed just outside the shack wall.

I obviously don't need any station “RF ground,” and never made any attempt to have one.

Lightning

I live in Los Angeles, which has the lowest incidence of lightning strikes of anywhere in the U.S. (fewer than 5 lightning incidents annually on average, and that's recorded in the mountains or high desert, not where I live). But, it doesn't matter. I grew up in New Jersey (70+/year) and have lived in Florida (90+ but it seems like a million), and have operated from many tropical places where lightning is so common that people miss it if it doesn't happen daily.

Fact is, grounding your equipment chassis inside your home doesn't do anything to prevent lightning damage, anyway. The last place you want lightning energy to find a path to earth is inside your home. The only place you want lightning energy to find a path to earth is outside your home. Volumes have been written on this subject by people more knowledgeable than I, so I'd refer you to those volumes for more information.

The only thing I'll say is, “Equipment (chassis) grounding is not helpful with regard to lightning protection.” And that fact ought to be self-evident to anyone who understands electricity.

Safety ground?

As I mentioned earlier, there are very valid reasons for “safety” grounding, although I've never once had an equipment fault that would have caused a safety concern whether the equipment was grounded, or not. But, it's possible. And, it's the reason that all construction in the past 30+ years in America (and many other places) used 3-wire grounded outlets throughout. The third (green, ground) wire should be connected to the ground buss in the building's electrical service panel, which should be grounded directly to earth via an 8' ground rod driven into earth at the nearest practical location, usually directly under the panel.

It's possible that even this excellent protocol can fail, but it's rare. In the event it does fail, a secondary earth ground for station equipment is a “belt and suspenders” approach that probably can't hurt. I must say, though, that having owned hundreds of pieces of AC-powered electronic equipment in my nearly 40 year ham career, I've never seen a fault occur that would cause an electrical shock during normal operation. So, I do believe this is a pretty rare event.

[I might also say that I've received numerous electrical shocks over the years, all of which were purely my fault (like replacing wall outlets and switches without bothering to turn them off first), so I deserved every one of them. And they didn't feel so bad. I can say from experience: 240v hurts much more than 120v. If you're going to shock yourself, go for 120. It's much nicer. In Japan, their mains voltage is only about 100 volts. Now I know why: It hurts even less.]

Daisy chain grounding

This is not recommended at all, but we all have it, in one way or another. Unless your station is set up an inch from your service panel, where a SPG (single point ground) connects every single thing going to and from your home and the impedance between all those items is zero: You, too, have some form of a daisy-chain ground.

This is nothing more than having equipment grounded via multiple paths, both serial and parallel, that have varying impedances to earth. It's difficult to avoid.

For example: If your antennas are mounted on your tower, and your tower's grounded, your antennas, unless completely isolated from their supporting structure, are grounded, too. Now, you use coaxial cable to connect those antennas to your station tuner, coax switches, amplifiers, rigs, or whatever, and you have a ground path from your antennas far, far away to your station equipment right in front of you, via all the coaxial shields. The DC resistance of all those shields is an unknown, although you could probably calculate or even measure it, if you try. But, if you have four antennas fed with four runs of 100 feet each RG-213/U, you've got four parallel ground paths that probably have a DC resistance less than one Ohm.

So, even if you disconnect every intentional earth ground you have in your station, your station equipment is still grounded, anyway. It's just a rather unpredictable ground. If you don't have a tower, but use a mast on the chimney to support your antenna, that mast should be grounded by a wire of substantial diameter directly to a ground rod via the shortest possible path. If you use a doublet antenna that is fully isolated from ground, then its feedline should be grounded via a lightning arrestor or similar device prior to entering your shack.

No matter how you cut it, your stuff is grounded (if you have an engineered installation), like it or not. So, the “safety ground” consideration, to prevent electrical shock in the event of internal equipment malfunction, is very likely covered. A 1 Ohm connection to earth will keep a 120v line down to 15v before it trips the 15A circuit breaker or fuse in a conventional household circuit. You won't feel the 15 volts.

If your home is equipped with 3-wire grounded outlets and your power supplies or other equipment containing AC-powered circuits have 3-wire power cords, now you have another ground, in parallel with that one.

If you added still another chassis ground simply because you wanted to, now you have still another ground, in parallel with the other two. But the circuit is more complex than just parallel branches to earth, and from an AC (RF) perspective it's more complex still.

As far as I'm concerned, the only important consideration in all of this is that the transmission line from my antennas to my station equipment should have considerably higher ground impedance than the outdoor ground connection from those same antennas to earth. So, when in doubt about that, I use more coax than needed for the path. This is purely a lightning protection issue, and I live where lightning hasn't been witnessed in sixteen years; but I try to follow that rule, anyway.

Still want to connect something to that little terminal?

Go ahead, if you want to. But think about why. “Because the terminal is there” isn't a very good reason. The little pictograms in the ham radio equipment owners' manuals (especially the JA stuff) isn't a very good reason, either. My Kenwood owner's manual has the little grounding pictorial, along with a warning to be sure the equipment is grounded, with no explanation at all as to “why.” Interestingly, I have lots of Kenwood audio equipment that doesn't even have a 3-wire power cord, and there's no ground terminal on any of it. Same company, different philosophy.

Maybe Kenwood believes that because amateur transceivers are capable of transmitting, they -- unlike receivers -- need a ground?

Even more interesting is the fact that the stereo equipment really could benefit from an earth ground. In one case of RFI I had personally, adding a ferrite choke filter to the AC power cord, and a chassis ground to a “surround sound” stereo receiver, completely eliminated the interference.

Let the flames begin

The “must ground” crowd - and there is one, somewhere - will likely disagree with all of this. That's fine. Remember, this whole piece is not about lightning protection in any way; it's about interior station equipment grounding. Since I've never used any in 39 years, I probably never will. I'm not suggesting that equipment grounding is wrong, just that it's usually unnecessary - and if you find it to be necessary, you've got other problems that can be fixed in other ways.

WB2WIK/6

Member Comments:
This article has expired. No more comments may be added.
 
Station Grounding  
by KY1V on August 17, 2004 Mail this to a friend!

Very interesting article Steve.

I would like to know more about the SWR information as I grew up with ham radio in the 70's and the SWR meter was an all important device needed for "adjusting your antennas".

Please do write another article about SWR. I would be interested in more details how to tune antennas with out the SWR bridge.

By the way, I am one of those guys with an 8' ground rod 2 foot from my shack and each device is grounded directly to a copper ground buss connected to the ground rod. No more than 4' from equipment to ground.

I think I may have to read your article a few times and dig up some old grounding information to better understand why I don't need it. Been a long time since I brushed up on grounding theory!

73,

David ~ KY1V
 
RE: Station Grounding  
by ZL2AL on August 17, 2004 Mail this to a friend!
Likewise!
I've been a ham for 50 years and never used an external ground in spite of all the dire warnings from the various men of letters in the usual radio handbooks. I have operated stations in this 230VAC part of the world and where I grew up in VE3 on 115VAC. Virtually any equipment I ever operated or built had a transformer of some sort which took care of isolating anything inside the circuitry from the main supply. I have experienced "hot lips" Most of us old timers have. Quite exciting really! The usual cause was a badly mismatched antenna and the usual cure was some sort of circuitry which matched the antenna. Funny thing! Hot lips disappeared when the antenna was matched. Modern day gear requires coaxial connections from radio to amplifier to various other devices around the station. RG8/u coaxial braid puts the chassis levels of all the devices at the same level of ground. Our 230VAC power system here in NZ has a three pin plug - one of which is ground and the second pin is called "neutral" which is connected to ground and the third pin is "phase" which is actually 230VAC above the other two pins. Ground is no problem. Running a separate line from each chassis to a ground rod driven into the earth seems fairly redundant to me.
 
Station Grounding  
by W1CAR on August 17, 2004 Mail this to a friend!
I'm an electrical contractor by trade, so grounding anything is of profound interest to me. When I first became a ham, my theory was "let the station float," that is, until I saw what floating a station can do when induced lightning surged through one.

Lightning will strike, no matter what, when and where it wants to, despite any and all efforts we attempt to thwart it, or lessen the chances of being struck. Nothing will protect you from a direct strike. Nothing. Near strikes are not preventable either, but making an attempt to give the static another better route away from your precious station equipment is what I try to do.

When you leave the house, remove your rigs from the potential of being struck. A rig sitting on the desk completely disconnected from the power grid and coax will not be at any risk of being struck. Simply disconnecting the coax won't do, as we've discussed already, the rig is still connected to the power grid and all it would take is for the static charge to find a small path through your rig to gound...and I've seen that happen. Lightning near-strikes almost always damage or destroy all electronic devices in a home that give it a minor branch path to ground. This only happens because the static has no better place to go, so it finds many paths to dissipate itself quickly.

RF gounding is something I have not found to be useful unless I'm connected to a battery-only power grid that floats, and I key up and get a burn from my rig. When I go HF portable I bring a small 12" ground rod with some #14 standed cable and that takes care of that. Plus, I've noticed I get better signal reports.

RF grounding in my home station isn't something I have done either.. because my lightning ground outside one way or another provides that, via the ground braid in each run of coax. I have never had any problems in my shack due to lack of "hooking up something to that screw on the back of my rigs." The only arguement I can foresee here would be to provide your rigs with a "better" path to ground for proper RF grounding.. but that still lacks merit in my honest opinion.

So, bravo. Good thread. RF grounding seems a little overrated to me.. maybe we should have a good article written on lightning grounding sometime to add to this discussion.

 
RE: Station Grounding  
by KA4KOE on August 17, 2004 Mail this to a friend!
One should never forgo a safety ground. More people are kilt outright by good ole 120 VAC, 60 Hz, than anything else.

 
RE: Station Grounding  
by WIRELESS on August 17, 2004 Mail this to a friend!
One purpose of a chassis ground is to keep the potential difference the same on all equipment metal thats within your common reach. The chassis of a 'grounded' through the ground on a 3 wire plug can raise above ground level. There are many reasons why a metal grounded object like radios, electric stoves, air conditioners, refrigerators, etc. can go above ground level. I got one of the biggest shocks I ever got from touching a grounded electric stove and a water pipe because there was current flowing though the ground wire back to the box caused by another appliance.

Also keep in mind that most power strips are really cheaply made and I have seen grounds float inside of them.

Shorted or leaking transformers, bad insulation within equipment, fault current of an improperly wired device on the line branch, improper connections in the service box, regular and common leakage from some devices, etc. can cause a hot chassis even though they are grounded through the 3rd wire.

Even RF potential differences can result between equipment since regular ground wires can act as quarter wave transformers instead of grounds.

Making a general statement that chassis grounding is 100% unnecessary is stupid and indicates an uninformed opinion. The author should run his nonesense on engineers that design grounds for hospital equipment. They will laugh at him.
 
Station Grounding  
by AL2I on August 17, 2004 Mail this to a friend!
Good article, and something I have seen in the commercial world as well. Many communication centers work fine for years, and then an expert engineer comes in for an appraisal and as soon as you can say "massive boondoggle", a grounding project is underway. Usually it is the bugaboo of "grounding loops" that sets off the flurry of sub-floor reverse copper mining.

Now there is a specific installation error that is pretty common in communication centers where the DC return is actually connected through the station ground rather than through the DC return, and this could (rarely) cause mischief, but I don't think Ham shacks would normally ever have this problem.

Steve (Super Elmer) Katz has done it again with another excellent sharing of his expertise.

Dave/al2i
 
Station Grounding  
by KW4N on August 17, 2004 Mail this to a friend!
Steve: Good pushback article on common myths. There can't be enough of these since it's almost impossible to change strongly held beliefs. Many of these myths are perpetuated by slick marketing schemes to sell equipment. One common scheme is the cleverly written commercial disguised as an educational article. Lightning protection infomercials come to mind. They would have you think that unless you buy $100. of their equipment before you throw your transceiver switch again, you would be committing suicide.

Mark Twain said it all: "A lie can be half way around the world before the truth gets it's boots on."

With your relevant reference to the "SWR" myth, here's the truth on this matter written by people who knew something about electricity.

http://www.qsl.net/k4mg/Antenna%20Design%20the%20Easy%20Way.htm

73's
Dave
 
Station Grounding  
by AL2I on August 17, 2004 Mail this to a friend!
Wireless: What you say about grounds is true, especially your note about how RF sees those grounds, but I wonder if you have even read the entire article. You've re-characterized what was said, and most significantly, Steve did not say grounds were bad. I've always grounded equipment that had high voltage finals, and I suppose Steve would too.

(As I type this, my hands are inches away from my 25,000 volt CRT with nothing but the ground in a standard three-prong plug to protect me, and it is located a mere 12 inches from my 500 watt computer.)

73
Dave/al2i
 
RE: Station Grounding  
by K3ESE on August 17, 2004 Mail this to a friend!
I always had a bad feeling that I was being lazy and unsafe with my ungrounded station. Those days are over, thanks to you, Steve! My head is held proudly up now.
 
RE: Station Grounding  
by AL2I on August 17, 2004 Mail this to a friend!
Well, if you've never grounded in 39 years, then I guess you've not grounded the older stuff with high voltage finals. I assumed you would, but on a re-read, it seems that you wouldn't.

For the record, I feel any glow in the dark gear should be grounded for both simple safety principles, and for RF containment principles. RF signals at high voltages are harder to contain than RF signals that are derived from current-based, solid-state equipment.

73,
Dave/al2i
 
RE: Station Grounding  
by KT3K on August 17, 2004 Mail this to a friend!
I agree.

I haven't checked the schematic for my Astron power supply, but I'll bet it has an isolation transformer in it anyway. If you count on your third wire ground in your home A/C, you should have a ground rod outside at your electric box for your home. Some older homes use cold-water-pipe grounds. And those can be problematic. I would say it would be wise to specifically ground your station if your home uses cold-water pipe grounds. As for lightning, I grew up in Tampa, the lightning capital of the world. For a nominal fee the electric company, (TECO in Tampas case), will sell you or install a lightning arrester for your home. It's nothing more than a special fuse that goes in at your meter. It will blow protecting your appliances in the event of a lightning strike. If it blows, you get to buy another one. It's saved tons of equipment, but of course, nothing is 100% sure with lightning. You could have your equipment unplugged and lightning still get it.
As for hospitals as mentioned in the thread... most hospitals have two types of grounds. A regular ground which is used for standard electrical equipment and appliances, like elevators, A/C and refrigerators, and an isolated ground which is used for computers and medical equipment. Ground potential differences can be a concern with some of the sensitive equipment they use, and differences in ground potential throughout a hospital at different stations could cause a lot of problems with equipment, medical and computer-based. Within buildings many elevator systems use high induction motors, and these motors put out quite a bit of load on the circuits they're on. So electrical system designs within buildings usually separate the high-induction motor systems onto separate circuits, on the regular non-isolated ground, and away from computer circuits.

Anyway, my station seems to run fine without running a special ground. Of course I do run a copper braid ground from my tuner ground to my radio's ground terminal.

Interesting thread,
73 John
 
Station Grounding  
by KB9WQJ on August 17, 2004 Mail this to a friend!
Steve,

You said: " I use my amplifiers as antenna tuners ". Never having been QRO, can you explain this a bit? Do amps not need to "see" 50 ohms? There are "legal-limit tuners" out there...unneccesary?

Thanks. I appreciate the info and will eagerly read your answers.
 
Station Grounding  
by OBSERVER11 on August 17, 2004 Mail this to a friend!
I will add this, I DO GROUND. I am not as rabid as some, my ground is only to prevent noise. I have several computers in close proximity to my ham gear and receivers. I ground the computer chassis'

YES! I KNOW, the computer case IS at the AC Main "ground potential", that is, the computer case is connected directly to the ground pin on the AC cord, so I am being redundant.

As a result of having the computer case as well as the radio chassis at the exact same potential, I do not suffer "ground loops" and my CRFI is minimal.
 
RE: Station Grounding  
by K5DVW on August 17, 2004 Mail this to a friend!
Count me as a "non station ground" vote. I've been operating ham stuff for about 20 years and never had a station ground. Lots of RF grounds and certainly a lightning ground, but never have I connected that funny little screw on the back of the radio to anything. I figure the braid of the coax back to the lightning ground would serve a better purpose than the AC plug ground anyway.

I think the most important point is to have good engineering practice when setting up a station.
 
RE: Station Grounding  
by W3JJH on August 17, 2004 Mail this to a friend!
OK, based on my experience around 250 W to 50 kW MF and 10 kW to 500 kW HF broadcast transmitters, I'm one of the "must ground" crowd. Here are my reasons:

1. AC Mains Safety--sometimes the insulation fails in equipment. If all exposed metal is either grounded or double insulated from live conductors, then a single insulation failure will not cause a dangerous condition. Normally, we can get a mains safety ground from the green wire in the power cable, but some equipment may require a separate ground wire.

2. RF Safety--when antennas are matched and balanced, there should be no RF in the shack. But antennas, balun, and feedlines can fail. Proper grounding provides a return path for the RF before it gets to the operator.

3. Home Owner's Insurance--almost all policies written in the US require that the wiring in the insured structure met local codes. Almost all jurisdictions incorporate the National Fire Protection Code into their building codes. Section 250 covers grounding and includes a subsection for Amateur Radio stations. If your grounding is not compliant with NFPC 250, then your insurance carrier probably will not have to pay any claims.

So, is everything grounded in my shack. Of course not. None of the low-powered, battery-operated gear is. There's no shock hazard, and any of the antennas that gear might be connected to are grounded by the lightning protection system.

There are lots of things that "work" but aren't really safe. Proper grounding is a safety feature. Ignoring it is like chambering a round in a M1911 and then putting it back in your holster with the hammer still back and the safety off. You probably won't have an accidental discharge ...
 
Station Grounding  
by K6XR on August 17, 2004 Mail this to a friend!
Thanks for a very good article Steve, I totally agree on both topic's, swr and grounding. My station operation is similar to Steve's and I do not use an external ground rod outside the shack for any type of grounding. Everything works well from qrp to qro.
 
Station Grounding  
by WIRELESS on August 17, 2004 Mail this to a friend!
Another huge falacy is the belief that RF grounds are not necessary if ....blah.....blah....blah.....Hams that run high power will find RF in everything in the house from low levels to very high and noticeable levels. RF can reenter your shack though any kind of wiring like cable, 240ac power line, AC grounds,even pipe near ground level, etc. Why? Because RF is induced into all wiring near an antenna to some extent. If there are no RF grounds, then the RF will just continually float. It has no path to ground by definition and thereby can cause all kinds of weird potential problems.

And if all you no RF ground type hams would actually put even a poor RF ground into your shack you will probably find the noise in your receiver much lower.
 
W4UDX style lightning protection  
by W4UDX on August 17, 2004 Mail this to a friend!
I always keep an eye on the weather. If a storm is approaching, I take the following steps:

1: Shutdown equipment and disconnect all power cords from AC mains.

2: Disconnect phone lines from wall jack to protect modems, phones, etc... (this is the path in which most computers are damaged by lightning).

3: Disconnect antenna coaxs and stuff the ends into a heavy duty Mason jar located away from the operating desk(except the one that goes to the antenna tuner, rig, etc... leave that one out of the jar).

4: Use battery powered equipment with indoor antennas (like J-poles) to communicate with weather nets.

This will effectively isolate all station gear from lightning. I also do this before leaving for vacations. The only way my rig will get blown out by lightning is by a direct strike to the radio. If that happens, someone is sending me a message and it is time to give it up anyway!
 
Station Grounding  
by K8AG on August 17, 2004 Mail this to a friend!
Not a bad article Steve but there is one reason for having a decent ground to a transmitter, cheapness. Not having a good RF ground for a transmitter can result in high RF voltage on some bands etc. This roduces a significant ouwee on my fingers as I key the transmitter from a device on the transmitter "ground". I am simply too cheap to buy an artificial ground and I find a 1" braid to a ground rod to be much cheaper and has no moving parts.

SWR (actually reflected power) is more important for the solid state radios than the tube radios many of us started with. Heck my first transmitter runed up into a lightbulb and simply connected to an antenna that probably was no where near 50 ohms. We can spend hours trimming and adjusting our transmission lines for absoulte minimum SWR, or we can spend the time operating our station.

73,

JP, K8AG
 
RE: W4UDX style lightning protection  
by WB2WIK on August 17, 2004 Mail this to a friend!
I don't reply to people who don't identify themselves, so can't respond to some of this.

Regarding using an amplifier as an antenna tuner: This applies to tube-type amps, which all of mine are. Most all commercial (and all of my homebrew) tube amps have fairly wide-range matching units built in, although they are normally set up for an unbalanced line, like coaxial cable. The typical "pi-networks" and "pi-L networks" used in most HF tube amplifiers are there for one purpose: To transfer power from the tubes to the load. They are tunable. If you can transfer power efficiently and within the tuning range of those networks, you're done.

My own amps (all seven of them, including the VHF ones) can transfer as much power into a 2:1 or 3:1 mismatch as they can into a perfect match; as such, the tubes don't dissipate any more heat than they would, for a given output power, if the load was a pure resistor like a dummy load. If this can be accomplished, and with tube amps it usually can, there's no need for external tuners or matching networks.

I do use a high-powered tuner occasionally, for an end-fed wire antenna, or for balanced line fed antennas, or to use an antenna that very badly mismatched, e.g., an antenna not intended for use on the band where I'm using it. Those, for me, are rare situations that occur most often in "the field," and not at home.

The "high end" solid state amps like the Quadra have internal automatic antenna tuners, alleviating the need for an outboard one unless the antenna is an unusual load, as discussed in the paragraph above.

WB2WIK/6

 
Station Grounding  
by ON4MGY on August 17, 2004 Mail this to a friend!
Great article from a great ham. I think Steve is one of the most active elmers here on eham and he seems to know just about everything you want to now. I just don't know where he gets the time to use his ham-equipment from time to time(hihi).
Many thanks Steve and keep up the good work.

73

ON4MGY Nic
 
RE: Station Grounding  
by G7HEU on August 17, 2004 Mail this to a friend!
Ditto what Nic said.

Steve
M0HEU / G7HEU
 
RE: Station Grounding  
by W6TH on August 17, 2004 Mail this to a friend!

Station Grounding.

Ground your radio and don't leave home without it.

Run a ground lead wire to each and every ham electrical device, then rest at ease.

Ground your radio and don't leave home without it.

AC/DC radios back in the old days were grounded to the 120Vac lines through a capacitor. Underwriters Labs, required by law.

Back in the old days the finals contained the Pi-network and had no need for a tuner and no need for the VSWR as the network was the tuner. We did ground all of our radio equipment in the old days, whether needed or not.

Our receivers were grounded as some signals would develope a 60 cycle buzz and the ground would eliminate this buzz.

I could mention much more, but will keep my notes short. My ham time of 66 years, from 1938-2004.

Nice article Steve, thanks for your time.

.: W6TH
 
RE: Station Grounding  
by KC8SBV on August 17, 2004 Mail this to a friend!
Wonderful!! Keep up these wonderful instructive articles. They are awesome! Super Elmer indeed!
 
Station Grounding---Good Article  
by TG9AKH on August 17, 2004 Mail this to a friend!
Congratulations on a nice, well argued article.

Your point is well taken---certain types of ground are either unnecessary or redundant. Additional "grounds" sometimes only increase the redundancy level of the already unnecessary. Yet, you left open the possibility that under specific circumstances, grounding may serve a useful purpose.

Perhaps your recommendation boils down to the need to use sound judgement, to know *when* those special circumstances have arrived.

This issue with redundant station grounding reminds me of the "all knobs to the right" attitude (disclaimer--I was once Mr. All Knobs to the Right myself). By this I mean that tendency to max out everything in a rig: max rf gain, max NB, max NR, max mic volume, max compressor level, max power output, max *everything*. I guess a logical step would be *max grounding* (?) Is there a knob for that?

WIRELESS:
You made some interesting points in the beginning of your comment. Later, you started using words like "stupid", etc. I forgot about your points, the only thing I remember is that you used the word stupid. I guess that's what you wanted.
 
Station Grounding  
by OBSERVER11 on August 17, 2004 Mail this to a friend!
re your stereo grounds.

There are only three grounds (same contact points, different connectors) on a stereo system... one is for your AM antenna, if you use a long wire, you get a ground point, one is the FM terminal for those that use coax, they provide you a point to screw the shield down, and the third is the most important for lovers of antique records. Turn tables must be grounded to prevent/reduce 60cycle hum.

So if you do not listen to AM, do not use a central antenna for FM and have gone CD, then there is no need to ground the stereo.
 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
W6TH, I haven't been a ham 66 years, but I have been one almost 40 years and in "the old days," for me, I never grounded anything inside my shack. Antennas and towers outdoors, yes. Equipment chassis indoors, no. Never saw any reason to do so, and still don't.

As for the "grounded by a capacitor" for the old AC-DC radios, and "Underwriters Laboratories, required by law..." this doesn't make much sense. A capacitor coupled ground is not a ground. Every item we have with a metal case or chassis is capacity coupled to earth in some way, it's only a matter of value. Is .01uF sufficient? How about 1uF? How about 10 pF? Nah.

Underwriters Laboratories is an independent product test laboratory with absolutely zero ties to the government or to any legislation. Because U.L. prescribes something as a standard doesn't make it law; never did, still doesn't. An even older product safety test and recognition organization (than U.L.) is VDE in Germany. They don't make any laws, either.

You might note that the ring voltage on a telephone line is potentially lethal but telephone equipment carries no U.L. recognition. FCC Part 68, yes. UL, nah. Doesn't need it, never did. AT&T protested the UL monopoly 50 years ago and all the Baby Bells that emerged after their divestiture carried on in that tradition.

I do have substantial experience in this area.

WB2WIK/6
 
RE: W4UDX style lightning protection  
by WILLY on August 17, 2004 Mail this to a friend!
As usual with WB2WIK's articles, a very well written, easy to read piece. Lots of food for thought. Thank you for taking your time to do it.


Is it possible, since we live in a world where everyone is ready to sue anyone they possibly can, that the equipment manufacturers are providing themselves an escape, should a user receive a shock? Along comes the user to sue, and if the manufacturer can find ANYTHING about the use of the ground lug that does not comply with their instructions - viola`, they can get out of the suit.
This may not be the main reason for the lug to be there, but it is interesting to consider.



"My own amps (all seven of them, including the VHF ones) can transfer as much power into a 2:1 or 3:1 mismatch as they can into a perfect match; "

How does one go about measuring this?


I'm thinking that it requires more than a typical watt meter. Wouldn't it also require a watt meter that measure reflected power? You are comparing the two readings and finding them to be equal?
 
RE: Station Grounding  
by WILLY on August 17, 2004 Mail this to a friend!
by WIRELESS on August 17, 2004

"...
And if all you no RF ground type hams would actually put even a poor RF ground into your shack you will probably find the noise in your receiver much lower. "


WIRELESS,

In your opinion, what makes an excellent RF ground? a poor RF ground?
Please describe each, and an example of constructing them.

Tnx
 
RE: Station Grounding  
by KE4MOB on August 17, 2004 Mail this to a friend!
3: Disconnect antenna coaxs and stuff the ends into a heavy duty Mason jar located away from the operating desk(except the one that goes to the antenna tuner, rig, etc... leave that one out of the jar).


The jolt coming down your coax has traveled thru a couple of miles of air. How is 1/4" of glass going to stop it? I definitely wouldn't want to be in the shack when lightning does strike! Can we say shrapnel??

Plus, I think this might be the worst thing to do. My reasoning is this: by placing your feedline in a jar, you are not allowing any static charge to bleed off. Your antenna becomes a flashing neon sign to an oppositely charged cloud saying "strike me!! strike me!!"

I think the best thing to do is have the feedlines directly attached to ground during a storm. That way, the charge bleeds off and in the event of a strike, the lightning won't have to go down the feedline, through the jar, across the room, and *then* try to find a path to ground.
 
RE: Station Grounding  
by K4JSR on August 17, 2004 Mail this to a friend!
Steve, you forgot about when your parents would
"ground" you in your younger days! ;-)
Also you evidently avoided "ground loops" with your
aero-plane!
I use an 8 ft. ground rod and common point grounding
on my station just because I "feel" better about.
No valid technical reason other than when I use my
135 ft dipole as a center fed "long wire" on 160.
Even then I am dubious as to any benefit, but that is
also why I have a 4 leaf clover in my shack.

I can remember when I was a mere lad and was being
Elmered by Bubba Borne, W4ZD (SK), going outside of
his (literally) shack to get a drink of water from
hose spigot just outside the door. As the water flowed from the spigot and the ground, and my shoes,
got wet the faucet would come alive with electricity
and leave me doing a souped up "Teaberry Shuffle"!
Bubba, and other adults would just hoot and laugh at my plight before rescuing me. Bubba would then try
to get me to explain how a water pipe coming straight up out of the ground could do such a thing to me.
Naturally, being a youth of just 12 I was totally baffled by the phenomena. Bubba finally explained that the water pipe was laid in the same trench to his shack as his AC power line. The water pipe had
oxidized sufficiently to insulate itself from the
ground and pick up some high (fortunately for me!)
impedance coupling to the power line.
He also taught me that when he turned everything off
in the shack that the problem would go away. He was
able to teach me a lot about the effects of current
flow, and other marvels of electronics. I miss him!
The moral of the story? All that glitters is not gold. All that appears grounded ain't!
Thanks for giving folks the "dirt" on grounding.

73, Cal K4JSR
"YIPE!", Ga.
 
Station Grounding  
by WA0ZZG on August 17, 2004 Mail this to a friend!
This is interesting how much variation there appears
about grounding. I'll pass along what I have learned
from working with commercial towers and microwave
systems.
1. Never directly ground radios. All that does is
attract lightning energy to the radio.
2. Ground antenna systems at the tower base, the
building entrance, and at the radio connection.
3. Make sure the radio can only 'see' one ground system. Never put a radio in a loop between two
different ground points. Most equipment is not damaged
by a direct strike, but by a nearby strike and the
resulting surge energy looping from one ground system
to another. Include the power company ground in this.
4. Go find what polyphaser means. It's expensive,
but worth it.
5. It fun when you are standing next to the owner,
have a direct strike on a tower, and nothing happens.
Dave...
 
Station Grounding  
by N6TZ on August 17, 2004 Mail this to a friend!
RIGHT ON STEVE!!!!

Grounding is such a mis-understood topic, and you will have many nay-sayers to your essay.

Just yesterday, I was discussing this with a friend who had put a ground rod in the yard and ran a wire upstairs to his 2nd floor equipment. He is feeding a dipole with a balun and coax. I suggested that upstairs, he should consider not only disconnecting the ground wire from the yard (it does absolutely only trouble), but also putting in a two wire AC plug adapter and abandoning the AC green wire. I doubt that these ideas were accepted.

On the contrary side, my equipment is ground floor and 3 feet from my radial system outside. I run 4 inch copper strap from the radials thru the wall and to my station equipment which is all 2 inch strap star configuration ground....Why? because about 15 feet away on the back side of the house is my shunt fed tower pumping RF back into the room and into the electrical house wiring....Oh, did I add that my equipment AC plug does not ground to the green wire? Think about it.

There are reasons to think through these various needs. I thought I would throw two extreme cases into the brew.

If nothing else, remember that ground is not always ground, it may be an antenna.

Hal, N6TZ

 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
To determine a matching network's (or amplifier's own tuning network's) ability to transfer power efficiently to loads of varying impedance, I use resistive oil-cooled (dummy) loads of different resistances, with thermocouples to measure the rise in the load.

I have loads at 20 Ohms, 50 Ohms, 100 Ohms and 200 Ohms that are commercial and pretty beefy and good to the low SHF spectrum, but homebrewed loads could work well on HF. The Calorimeters are all commercial (HP, now Agilent).

I've never seen an HF amp with a pi-net (yet) that couldn't deliver the same power into 20 Ohms, or into 150 Ohms, as into 50 Ohms.

Another way to measure this is thermal rise in the amplifying devices themselves, converting Calories to Watts and then subtracting that from DC input power measured the conventional way. If you have 1000W DC input and 500W dissipated in the tubes, what remains ought to be output power (500W) unless you have components in the plate circuit getting mighty hot.

If you make this measurement with various terminations, re-adjusting the network to accommodate those variations, and see any notable difference, I'd be very surprised.

Usually, you can tell if the amp's tuning network has sufficient range to accommodate your load: Output power will peak within the tuning range of the variable components, and the DC indications, including plate and grid currents, will be about the same as they are when using a 50 Ohm dummy load. If those two conditions occur, I'd bet dollars to donuts your amp is very happy with the load and delivering as much power as it would into a 50 Ohm load.

My 75/80m antenna has a bit over 3:1 VSWR at both band edges and I've never even thought about using a tuner to correct that. My 160m antenna is well matched at 1815 but about 4:1 at 1870 and I use it up there all the time (AM contacts!) without a tuner. The amp is my tuner, and if I can keep plate dissipation and grid current within tube ratings, it's very happy.

WB2WIK/6

 
RE: Station Grounding  
by KC8VWM on August 17, 2004 Mail this to a friend!

I would be interested to know if any studies have been conducted from anyone that actually had lightning strikes.

For example, a lightning strike resulting in damage from a person WITH grounded station equipment vs. damage caused to a station without any station ground at all.

Fact # 1

Communication centers like police and ambulance dispatch centers operate during lighting storms.

Fact # 2

Same holds true for AM/FM and Television broadcast stations.

Cell phone tower antennas are not the only thing grounded at a cell phone tower site. The equipment is also grounded. Why not just let the equipment float?

What do these cell phone tower and other engineers know that we do not know?

Why do these places protect themselves from potential lighting damage? Should they even bother if the main antenna is already grounded?

Some argue this point, "Why provide a ground path inside your home for lightning to travel"

Why would anyone not think that the coax cable going into your home from your antenna is already providing that path? Station ground or no ground aside.

Therefore, I would ask:

Should lighting terminate at your station equipment, or do you provide the static electricity with a means of "escape"?

True there is not much you can do against a direct hit, however, why wouldn't you want to make some reasonable attempts to minimize any possible damage from occuring?

Here are some resources:

"Observations from Sandia Laboratories lightning testing (6.3) confirm that lightning exhibits radial horizontal arcing in excess of 40m. This ground surface lightning spreads according to local soils impedance characteristics, resulting in step and touch voltage hazards. Capacitive, inductive and ohmic attachment processes also come into play (6.4). Victims insulted while near trees, or touching electrical appliances, or in contact with water or other unintended conductors often are recipients of fatal currents and voltages after lightning strikes them indirectly."

Source:

http://www.lightningsafety.com/nlsi_lls/deaths_injuries01.html


"The potential increases on the earthing and on all earthed metal parts of the object relative to the zero potential at a distant point. It may reach a very high value but it does not cause any danger if the potential differences inside the object to be protected are limited. Potential equalization is realized by the bonding of all extended metal objects."

Source:

http://www.lightningsafety.com/nlsi_lhm/rtaf3.html


73

Charles - KC8VWM
 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
Charles, some of this stuff is pretty irrelevant, if you think about it.

Commercial BC stations, at least for FM and TV, can have pretty poor grounds because they're located up very high above ground. For example, most NYC FM-TV stations are on the 82nd floor or above in the Empire State Building (espcially now since WTC no longer exists -- but when WTC was active, the transmitters were higher than that). This is almost a thousand feet above earth. Grounded? Hmph.

Most telephone equipment is low voltage DC powered (usually by 48v, with a positive ground) by batteries. Many of the cell sites I've been to (most of them, around here) do not have the equipment grounded to earth, but rather to the positive terminal of the battery bank. Whether that's actually grounded or not is another issue, but in many cases, it's not. That equipment is very well isolated from the AC mains, so a "safety" ground is irrelevant; and RF ground is meaningless at 800-2400 MHz, where you couldn't achieve an earth RF ground unless your equipment was buried underground.

Regarding data on lightning: The tower on Empire was erected 60 years ago before current standards existed. There was no code, all the lightning safety councils didn't exist, Polyphaser wasn't born yet...and transmitters have been operating there all this time, more than 1200 feet above ground, where for almost 40 years that tower was the highest point in any direction for several miles. Amazing.

WB2WIK/6



 
Station Grounding  
by W5AOX on August 17, 2004 Mail this to a friend!
I am continually amazed at the quickness of some hams to immediately label someone like WB2WIK Steve Katz as "inexperienced", "naive", "ignorant", "doesn't know what he's talking about", etc.
How long have you been publishing real-life technical articles in electronics magazines, Steve? I think I remember one from almost 20 years ago, on homebrew receivers. I've also been jealous of your experience, expertise, and success on the VHF bands both high and low power.
I have been in the electrical and electronics field since about age 16 or so, and have tried both sides of the "Ground for Safety Etc." fence. I have experienced TWO direct or close-to-direct lightning strikes in my 20+ years of hamming with a tower pointing up to the sky. The first occurred while living in my brother's house in Carlsbad NM (a very active lightning area). We were sitting in the kitchen when the stroke hit the tower. The lights in the house turned almost double-brilliance for several seconds as the ground and house literally shook.
When I opened the door to the garage where the hamshack was, I smelled smoke... and burning electronics.... a bad sign. All coax had been disconnected prior to the storm but lightning had flashed across the bench in various areas from the coax entry points to anything plugged into the wall. You could see the carbon-paths across the wooden bench.
That tower was grounded, but it did not keep lightning from striking, and more damage occurred then than the second strike which hit at a different house some years later which was NOT grounded, other than thru the guy wires and base section of the tower.
The tower in Carlsbad may have actually have saved the house from damage. When my non-ham brother lived there, 2 years before MY lightning strike, he had experienced a large lightning strike. His neighbor told him he saw the strike seemingly hit the garage.
When he looked around in the garage, he could see little evidence of damage.... but he did notice an almost-straight line of spikes stuck up in the sheetrock ceiling of the garage. When he tried to figure out how they got there, he noticed a crack in the concrete floor just below the string of shards in the ceiling, and realized the shards were splinters of CONCRETE, literally blown into the ceiling from the floor when the lightning penetrated the roof. Upon close examination of the roof, he found, directly above the cracked concrete and shards, a small scorched slice in the roof. Evidently lightning had just SLAMMED its way through the roof and hit the floor..... avoiding the AC entry wiring and grounded conduit halfway across the room.
I fail to see how grounding could have prevented damage from either of these strikes.... lightning is so unpredictable. I have often wondered if, by taking pains to ground our stations, we are not actually risking increased attraction for lightning strikes.
I was once caught in a storm with frenzied lightning, hail, and thunder, and had to pull off the road right across from a 700' TV tower on my left. I couldn't see to drive further, but I noticed I could see the top of the tower through various holes in the storm, so I watched to see how many lightning strokes would hit it. I watched for several minutes, with lightning crashing all around, and NO visible strikes ever hit the tower. I looked around in other directions to see what WAS being struck by all the lightning, and was surprised to see most of the flashes striking OIL TANKS, short, large, and squat, with rounded tops, most of which were down in a small low part of the terrain. It seemed that the large surface areas of the tanks provided a very good grounding contact, and though the lightning had to travel much farther down to hit them, hit them it did, and multiple times apiece.
I argued for an hour one time on 2 meters with a very vocal trucker-ham who had read prevalent literature (of course he was big on CB and associated literature) and was absolutely convinced the ground strap from the back of the mobile radio was necessary to form a good RF GROUND, in spite of the fact the feedline was coax, grounded both at the radio RF connector and the antenna feed point. When people have deeply held beliefs that they have not researched for themselves in "real-world" experience, it becomes like a religious belief..... it matters not that you may have years of experience in RF and AC power, you must just be a lucky dummy since you don't realize the TRUTH that was published SOMEwhere........
I would only disagree with your faith in the grounding via the AC outlets. Test them first, then trust them.
I once was trying to install a base station for a customer who was a LICENSED ELECTRICIAN. Every time I plugged in the power cord, the circuit breaker would trip. Turned out the AC outlet had the HOT and NEUTRAL lines reversed, and when the base station was plugged in, grounded through the coax and antenna pole, it shorted the AC mains and popped the breaker.
Glad I wasn't the long path between the "chassis ground" and the coax before the breakers started popping. At Los Alamos National Lab, we found we could NEVER trust an AC outlet; we had to check them all before plugging in equipment, even though all electrical work was done by union / licensed electrician tradesmen. They seemed to never wire outlets the same way twice.
So, though I agree "grounding your station and indoor equipment" is overblown and unnecessary (you must have a THICK skin to bring this subject AND SWR into the same article), I scream aloud: DON'T trust your house wiring (especially for safety grounds) until you've tested it!
 
RE: Station Grounding  
by W1CAR on August 17, 2004 Mail this to a friend!
""Underwriters Laboratories is an independent product test laboratory with absolutely zero ties to the government or to any legislation. Because U.L. prescribes something as a standard doesn't make it law; never did, still doesn't. An even older product safety test and recognition organization (than U.L.) is VDE in Germany. They don't make any laws, either""


What the Underwriters Labs has to say directly influences the National Electrical Code, and with it, local electrical inspectors, home inspectors, and insurance adjusters. What they say is followed by the NEC, and is the deciding factor in any legality when it comes to electrical grounding, and station grounding. Period.

National Electric Code is what we should be referring to here, not UL.

I am enjoying this discussion. I like a person who is opinionated because he knows things... not because he thinks he knows things. Bravo, Steve.
 
Station Grounding  
by NC2W on August 17, 2004 Mail this to a friend!
The prevelance (or lack thereof) of lightning strikes should never be a VALID reason to (or not to) ground.

SWR is almost never a problem in tube rigs. They simply disappate the reflected power as heat.

SWR in a modern rig, with transistored finals CAN pose a problem. Power reflected back to the finals, as heat can ruin a transistorized final.

Station grounding is not a panacea for trying to make a current type antenna out of an antenna acting as a voltage device. Having typed that, I'm not sure anyone said it was.

The purpose of a ground, is make an electrical connection between 'GROUND' and the chassis. Such a connection is required by NEC (Article 250.110 -250.114, and Article 810.20). No more, no less. To suggest grounding is wrong, or unnecessary is incorrect.

 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
W1CAR: UL may influence NEC, but the two aren't directly related in any way. Actually, UL1950, the standard for most of the electronic equipment we use daily, has been revised to UL60950 in accordance with European standards developed independently of UL by IEC.

Also, there is no requirement anywhere in America (or anywhere else) for equipment to be UL recognized. This is a voluntary thing, and lots of electronic equipment is not UL recognized, nor recognized nor certified by anybody. There's no law stipulating that it must; although in some cities, local Fire Ordinance requires that electrical or electronic equipment actually connected to AC mains for demonstration or sale must have an NRTL (like UL, or similar organization) or Fire Marshall tag clearly displayed on the equipment during such sale or demonstration.

NC2W: What can I say? If you believe reflected power is dissipated as heat in the power amplifier stage, you have it all figured out.

Golly!

WB2WIK/6

 
RE: Station Grounding  
by W1CAR on August 17, 2004 Mail this to a friend!
"W1CAR: UL may influence NEC, but the two aren't directly related in any way"

Thanks for the clarification. But, isn't that what I said?
 
Station Grounding  
by WA2KWP on August 17, 2004 Mail this to a friend!
Steve,

I really like the way you write and your choice of subject matter. I wish, however, you hadn't couched your article in the guise of an old wive's tale. The grounding issue is technically well known. The problem with your premise is that grounding is never necessary. It is in fact 'sometimes' necessary. It is difficult to know when. It would therefore seem prudent to ground as much of the installation as possible to cover yourself. As technology improves it may be possible to "ignore" grounding.

I don't believe you can mix the terms earth and ground. We should also not confuse the two terms, as each has a definite meaning. I believe the technical concept is that earth is a path for current to the earth, and ground is a common reference level for all elements.

About SWR. I remember from 55 years ago, as a young novice, extensive talk about SWR!! SWR was a concept well known to Hams of that time, and cause just as much conversation as it does now. Although true that there were no inexpensive pieces of equipment for measuring SWR with a number, there was a simple method of viewing SWR. This was to hold a florescent bulb against the twin lead transmission line during transmission. Not only could you load for maximum output by the brilliance of the tube, but you could actually see the Standing Waves marching up the tube!!!

I wonder if you are old enough to remember the Army training movies showing the soldiers marching up and down the transmission line representing Standing Waves. I also remember the "old timers" of that period saying that SWR was only one of the factors to be considered in design of an antenna, not the only factor. I believe they understood the concept very well then, just as most knowlegable amateurs understand it now. Although SWR was a mathematical concept; the numbers 4:1, 1:1 to represent SWR were common in conversation, and well understood, although essentially only theoretical. I don't remember seeing an SWR bridge until the early 60's, and didn't own one until Heathkit put one in their catalog. At that time I really didn't believe you needed one.

Keep up the good work. You are an asset to the understanding of Ham Radio Theory, and the Ham Radio Community.
David
WA2KWP
 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
W1CAR, yes, it is, although you went on to imply (I thought, at least to me) that UL has a strong influence on NEC, and that somehow UL will be influential in liability issues concerning grounding, should those arise. If I interpreted that correctly, I disagree with that premise.

UL representatives won't even testify, as far as I know, and are never an arbitor that I've ever heard about.

There was another claim in here, somewhere, about NEC requiring some specific method of equipment chassis grounding, which it does not, for any consumer electronic apparatus. Many consumer appliances still have 2-wire power cords and plugs, including some mighty powerful ones. Check your toaster, or your hair dryer, for example...

WB2WIK/6
 
Station Grounding  
by NA4IT on August 17, 2004 Mail this to a friend!
Good article! But an old gentleman told me how to keep my rig from getting hit by lightning:

(1) Unhook rig
(2) Place in styrofoam and original box.
(3) Place under bed

(Just a light hearted look at grounding!)
 
RE: Station Grounding  
by W6TH on August 17, 2004 Mail this to a friend!
Confused are you?


Ground is a common reference point in the radio circuit. "Ground Potential" means that there is no "difference of potential", no voltage between the circuit point and the earth.

The use of tube amplifiers in general practice is to ground the negative terminal of a dc power supply and to "ground" the heaters or filament for vacuum tubes.

There are ground and ground potential. When a connection is said to be grounded it does not necessarily mean that it actually goes to earth.

We need more theory on this subject and find what a ground is really all about. We may all have grounds and do not realize it.

.: W6th
 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
NC2W, I did look up your NEC references 250.110-250.114 and also 810.20 and to refer to these in response to this article is really a stretch. The 250.xxx sections refer to proper grounding of electrical outlet boxes and 810.20 refers to grounding of satellite antennas and such.

This whole article is about "equipment chassis grounding," using the ground terminal on the rear of your equipment chassis -- which NEC makes no reference to, anywhere, in anything. Ham gear is "indoor consumer electrical and electronic apparatus" by definition, and is not regulated by code.

W5AOX: Thanks for the comments. It's been a lot more than 20 years! My first technical articles published were in 1970, when I was 18 years old. I've been on a bunch of IEEE committees over the years and that was kind of fun, but it sure can get tiring working with groups of individuals who can never agree on anything.

WB2WIK/6



 
RE: Station Grounding  
by KC0LET on August 17, 2004 Mail this to a friend!
I just wanted to comment on sticking the ends of your coax in the mason jar. I have to admit I do that too. I don't do it to prevent lightning strikes or anything like that however. I will also mention nothing in my shack is grounded except for the safety ground provided by the third prong on the power cords.

Anyhow, I have a lightning ground system, with surge protectors in the coax lines, connect to a ground rod system that is also bonded to the tower. All of this system stays outside - you want to channel the lightning into the ground before it enters your house. Anyhow, I put the coax into a mason jar after an experiance a friend of mine had during a lightning storm. He had his coax unhooked and laying on his bench. He didn't have any surge protectors inline. With each nearby stroke of lightning, you could see a spark arc from the center pin of the PL259 to the outside barrel. Ever since then, he has advocated the use of a mason jar to prevent a fire in the shack.

Last summer I was in my shack disconnecting my coax during a thunderstorm. I had just finished and had turned and started walking out of the room. I had gotten about six feet from my bench when I was knocked to the floor by a very loud explosion like noise. Lightning had struck between my tower and the house. The tower is about thirty feet away from my shack, so I was only about fifteen feet away from where the lightning hit.

I suffered no ham equipment damage, except for the Radio Shack NOAA weather radio that was on my desk, and my computer network hub. The indoor antenna on my weather radio was nearly burned in two. My shack is in the basement with a false ceiling. One of the metal pieces that make up the support grid for it had a hole burned in it...it was still warm several minutes after the strike...explain that one...I still haven't figured it out, there are no wires running anywhere near the spot the burned.

Also, I have a furnace vent in the middle of my ceiling connected to the metal ductwork of the central heating and cooling system. The screws were burned out of the register. I really should take some pictures and post them.

Just a little reminder of the power lightning contains.
 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
W6TH, we have to meet for an "eyeball" one day and swap war stories about SSME and other space programs. I consulted to Rocketdyne ISD (Chatsworth campus) on ISS, on the SS Freedom power conversion designs, in concert with Boeing, Lockheed and Loral (at that time).

What a circus! But I'm sure you have some stories, too...

WB2WIK/6
 
RE: Station Grounding  
by AA4PB on August 17, 2004 Mail this to a friend!
Very good article. In my opinion, the one ground that is important (other than the electrical system safety ground) is grounding of the coax just outside where they enter the house. That is only for lightning protection. Disconnecting the coax cables and leaving them lay on the floor or sticking the ends in a mason jar may save your equipment but it is not likely to save your house. Actually it may not save your equipment unless you can get it out of the fire quick enough :-)

Other than the lightning grounds and electrical safety ground I have also never used a ground connection. Unless your equipment is setting on the ground it is usually pretty difficult to get a good RF ground to the rig anyway. If your antennas are properly balanced and located far enough away so that they won't couple RF into the shields then an RF ground is not needed.
 
RE: Station Grounding  
by K0IMJ on August 17, 2004 Mail this to a friend!
Steve, thanks for saving me a lot of trouble. I have been a ham for 47 years and really never grounded my rigs. That was my next BIG project. Being on the upstairs floor provided me with some problems, and delayed me from doing what I thought should be done. Now I am rethinking once again. I have quite a few tube rigs (www.heathkits.com) and I notice that when I record the lowest SWR for a solid state rig and then set it (the ant. matcher) the same way for a tube rig...sometimes the SWR is higher, or at least different. Would you write a COMPLETE article on SWR. I am one of those guys that is starting to realize how much I don't know.
Thanks and keep up the good work.
Gary K0IMJ (www.heathkits.com)
 
Station Grounding  
by W8JI on August 17, 2004 Mail this to a friend!
Station Grounding Reply
by K8AG on August 17, 2004 Mail this to a friend!
Not a bad article Steve but there is one reason for having a decent ground to a transmitter, cheapness. Not having a good RF ground for a transmitter can result in high RF voltage on some bands etc. This roduces a significant ouwee on my fingers as I key the transmitter from a device on the transmitter "ground". I am simply too cheap to buy an artificial ground and I find a 1" braid to a ground rod to be much cheaper and has no moving parts. >>>

I agree 100% with Steve. If your antenna system is properly designed and constructed and your equipment is designed well, there is absolutely no need for an RF ground in the station.

An RF ground is a band-aid for other more serious problems.

The exception to all of this is if you intend for your equipment and everything in and connected to your operating position to be a part of the antenna system, or if you have an antenna extermely close to station equipment.

For information on why stations have "RF in the shack", have a look at:

www.w8ji.com/common-mode_noise.htm

www.w8ji.com/verticals_and_baluns.htm

http://www.w8ji.com/end-fed_vertical_j-pole_and_horizontal_zepp.htm

Fix the antenna system, and the RF in the shack will go away.

73 Tom
 
RE: Station Grounding  
by W8JI on August 17, 2004 Mail this to a friend!
Anyone who thinks amplifiers dissipates reflected power as heat needs to review how amplifiers convert DC into RF.

http://www.w8ji.com/Vacuum_tube_amps.htm

"Reflected power" may make an amplifier run hotter or cooler if the tank is not retuned to match the new load impedance. If the tak is retuned, Steve is exactly on target. It makes no difference at all in ANYTHING except the current flowing from the tank to the output connector and voltage across the loading cap.

The tubes have no idea if the output mismatch is 1:1 or 100:1, as long as the tank circuit matches the load impedance. The normal range of a tank is 25 ohms to over 100 ohms, and is generally more restricted on bands like 160 and less restricted as frequency increases.

The oldest and worse myth is reflected power hurts the life of PA tubes.

73 Tom
 
Station Grounding  
by KB9YGD on August 17, 2004 Mail this to a friend!
Well You Can Allway`s Tell The ``NO GROUNDER`S`` On 75 With All The RF In Their Audio.Also You Ground Stuff And All The Voltage`s That Like to Bite UR Lip Or blow Out The Little Bulbs In The Tuner,Etc Are Tamed.And At HF The Ground System Is A Big Part Of The antenna System.73,``THE REAL HAM``
 
Station Grounding  
by WA2JJH on August 17, 2004 Mail this to a friend!
Great artical!
I have always maintained a good station ground since I got zapped
I learned this the HARD way 30 years ago.

I could not understand why when I touched my TS-520 and the sheild connector of the PL-259.

I got huge zap. I then learned about ground looping, floating grounds, and chassis ground.

I once measured a ground differential of 80VAC!
Try this for fun. Hook up an AC voltmeter between your
rigs GND stud and the outside of a pl-259 that is your antenna's ground at te other end of the feed.(Cable not connected to rig)
Do not be surprised if you do not see 0 volts!

I work with signals/equipment that statistical anaylsis are needed to see what is the output vs guassian and poisson noise.
Common chassis ground for all test equipment must meet very strict standards.

Have fun and be safe. A fringe benefit of being safe might get you to receive DX better!



 
Station Grounding  
by K3YD on August 17, 2004 Mail this to a friend!
I have to mention a time when I found radio grounding necessary.
I was operating CQWW-CW at an east-coast contest Multi-Multi using a new radio which relies exclusively on DSP for selectivity. In this high-RF environment, using an(ungrounded) transceiver, received CW was un-readable. The signals from 3 adjacent KW stations, combined with the strong signals being received on a 6-el Yagi were mixing to create something which sounded like CW sent by left-footed gorillas sending Japanese using the Cyrillic Morse alphabet!
I first inserted an ICE bandpass filter between exciter and amp, but that did little. However, as soon as the transceiver was connected to the station's ground-buss the insane mixing stopped and I could operate.
There are probably other solutions to the problem, but when a contest is 17 minutes old and 20 meters isn't producing, you grab at anything which works.

 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
Reflected power *does not* hurt the life of PA tubes?

Oh, crap, now I have to go digging in the trash to retrieve those 8877s :)

One respondant asked about tuning antennas without using an SWR bridge. This can surely be done, but in year 2004, I'd have to ask "why bother?" A decent commercial SWR bridge costs very little and is a great station accessory/test instrument that every ham should have -- now. My comments regarding this were attempting to point out that in "olden" days (not all that olden), many hams didn't own such instruments and somehow worked the world, anyway.

In many cases, they used antenna tuners and just tuned for maximum feeder current. A simple diode detector field strength meter could also be used to just tune for "maximum" indicaton, whatever it was, as long as the detected RF was coming from the antenna and not from the transmitter itself!

Then, many never matched their antennas at all and simply tuned for a plate current dip on their PA stage. That should correspond to about maximum output power, if the stage is properly loaded, and as long as you're running "maximum," who cares what that really is?

I'll admit as a Novice, and lacking an SWR bridge myself, I used received signal reports to affirm I was getting out about the way I thought I should. Every "599" report was such an affirmation!

WB2WIK/6

 
Station Grounding  
by WA1RNE on August 17, 2004 Mail this to a friend!
Wish I could I agree but there are at least 2 very common situations where connecting all equipment together to a central station ground is the safer play.

First, we are human and we make mistakes. Some are painless, some can be deadly or result in an RF burn, which hurt like hell.

Here are the 2 situations. I'm pretty certain that over my 30 years in HR, I'm not the only one that has made them: (Of course, some hams have better track records than others)

1) Running tuned feeders without a station ground;

If one leg of the transmission line fails or breaks, you now have a whopper of an unbalanced feed line and a high SWR to boot. The potential is high for some hefty currents floating around the shack, especially at 1.5 KW PEP. I would rather have my rigs at a lower RF impedance than becoming part of the voltage side of what is now potentially a multi-wavelength vertical antenna!! Anyone ever see/use that cheap ladder line with #16-20 solid conductors? Some homebrewed versions use soft drawn copper that can snap after being in the wind long enough.

2) Running older Boat Anchor vintage equipment along side of newer vintage gear;

Prior to approx. 1975 or so, most transceivers, receivers, transmitters, etc. were not equipped with a safety ground on their input line cords. Relying on the coaxial feedline to ground these rigs can be dangerous - especially if you decide to switch antennas manually or switch to a tranverter for VHF, etc., etc. Most people don't think of pulling the line cord just because they're tinkering with a coaxial antenna cable.

Summarizing, it's both good practice and in most cases inexpensive to run a station ground and can help prevent some unpredictable types of events - keeping you on the safe side of things if they do occur. I've been doing it for 30 years and haven't had a problem - unless of course I forgot to reconnect it.
 
RE: Station Grounding  
by AB5XZ on August 17, 2004 Mail this to a friend!
A friend recently remodeled a 1914-era home. The first electrical contractor (later fired) forgot to ground the electrical system. Symptom: alarm clock advancing at about twice usual speed. Once the ground was established, that problem - and some others - went away.

Moral: you can get away with it (no ground) sometimes, but you should really understand what you're doing and why.
 
RE: Station Grounding  
by W8JI on August 17, 2004 Mail this to a friend!
I'd like to add one more comment that is life and safety related.

While I agree strongly an RF ground is not required unless the station is intentionally or unintentionally part of the radiating antenna system, I just as strongly disagree with advice station equipment with ground lugs should not be grounded to a common safety ground.

Worse yet while reading through comments I saw a suggestion of floating the third wire of a grounded cord!!! NEVER float the third wire of a grounded plug!!! It is there for a good reason.

Line operated equipment with ground lugs should indeed have lugs grounded to a common SAFETY ground. It is poor advice to suggest we NOT ground equipment to a safety ground.

Ham equipment is different than conventional consumer devices like toasters. Toasters and other appliances are extremely well-insulated. They do not contain line bypass capacitors for RF filtering. They have well-insulated switches, and long intenal arc-paths. They don't have rear panel jacks that connect to the frame and allow other appliances to plug in.

Amateur equipment is very much different. It often contains large bypass capacitors, sometimes larger than .01uF. There is complex wiring, and much of it has minimal insulation to the chassis. There is often HV inside.

The Ham station is also very much different than a living room or kitchen. The Ham shack has wiring that runs outside, it has interconnecting wires that run between different pieces of gear. If a component fails and that particular piece of gear has a high resistance to safety grounds, you can be be killed. This can happen when you are reaching behind a radio to screw in a coaxial connector.

NEVER float the equipment to separate grounds, and especially NEVER remove or defeat grounding pins on cords!

Let's look at a vacuum tube power amplifier. If the HV supply is 3000 volts, a single common component failure can place 3000 volts plus 170 volts on the chassis if the chassis has no ground path to a safety ground!! Where is that failure? From the high side of the secondary of a supply to the primary winding high side of the power transformer. Without a chassis ground path, the chassis will come up to line voltage sinewave peak (a typical maximum of 170V)plus voltage between the hot end of the secondary and chassis of the amplifier. The ground path would be all that would cause a fuse to blow!

Only an suicidal fool would remove or defeat the third wire safety ground of an amplifer, or float the chassis from a common safety ground backup.

There are a lot of components that can fail and cause big problems. Say for example you have a slightly loose coax connector and no short common ground connections between your gear. All of that RF normally returning harmlessly on the inside of the shield now flows through whatever RF path it can find.

That path can be sensitive and expensive equipment. While an operator RF burn might heal, and IC chip is gone forever.

While I agree an RF ground is a sign of other more serious problems, a common ground in the station that has a path back to the power line safety ground is ALWAYS a good idea. The third wire of a power cord should NEVER be remove or isolated. Our equipment should always have a common ground, especially if high power is used.

We do not need a good RF ground in the shack if the antenna system is well-engineered and properly installed, but it is a serious safety issue for people here to suggest floating equipment is a good idea.

Don't worry about the RF ground if you have agood installation, but by all means make sure you have a common ground that is bonded to the power mains safety ground. Not doing so is just plain stupid.


73 Tom

 
RE: Station Grounding  
by AA4PB on August 17, 2004 Mail this to a friend!
Well You Can Allway`s Tell The ``NO GROUNDER`S`` On 75 With All The RF In Their Audio
------------------------------------------
Or perhaps the guys who are running a KW with the antenna directly overhead.
 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
I was rather surprised to read about anyone defeating their "third wire" ground, and was wondering if that was tongue-in-cheek or for real.

Nowhere did I ever imply equipment shouldn't be grounded. My article addressed adding "more" grounds, in addition to the standard safety ground already provided in an engineered station.

Of course, I could tell you all about an accident I had many, many years ago when I had a medium-tension (7200V) power line fall across the element of my 20 meter beam (seriously). I had no auxiliary station grounds of any kind, but everything was grounded, anyway, and here's what happened:

7200V line fell on antenna and just hung across it. Came into the shack the next morning to hear a peculiar humming sound. It sounded like it was coming from my HF amplifier, but couldn't be certain.

I felt the amp, it was cold, but really did sound like it was humming (like a transformer lamination problem). So, I unplugged the amp from the 240V power line, and the humming stopped. What the heck could cause that? The amp was "off," of course, even before unplugging it.

I felt the AC power cord between the 240V wall outlet and the amp, and it was warm. What-?

I started feeling other stuff. The coax cable from my 20 meter beam, where it plugged into the station coax switch, was also warm.

The path from the HT line to ground was through my coax, the coax switch, the patch cable between the switch and the amp, then through the amp and its power cord, into the 240V outlet. That was the path, and it was conducting considerable current, which is why everything in the path was warm.

I went outside and looked "up" and saw the cable laying across the beam element. I wondered, "Why doesn't the return path go through the tower?" and then remembered this was an isolated-feedpoint beam with no return of any kind to the mast or tower, and my only balun was a coil of coax, used as an RF choke.

So, this is one example of something that could have been a pretty bad scene, saved by ordinary coax and 4-wire 240V power cord. I never did figure out what the humming sound was, but after having the power company shut down the line and replace it (which they did in less than two hours, once I called them!), the hum never recurred.

I wonder how much current it took to get the RG-217/U that warm? Probably quite a bit....

WB2WIK/6
 
NEC Quoters  
by K0BG on August 17, 2004 Mail this to a friend!
When I first saw Steve's article (please note the correct spelling of article–it isn't spelled artical!) this morning, I thought just like Steve did in his last paragraph (the title therein)—let the flames begin!

A lot of the flames quoted the NEC (National Electrical Code) as reasons for or against proper grounding (or lack thereof). I have this to say:

Before you quote a well-known (and accurate) source, you best have read it at least twice, and preferably several times and know EXACTLY what it says. Steve's article was intended (I'm sure) to separate fact from fiction. Unfortunately, the very information Steve used to document his position was (has) been misquoted and misconstrued to suggest an alternate view.

For those who disagree and quote the NEC, go read it again, several times!

Alan, KØBG
www.k0bg.com
 
Station Grounding  
by K0QX on August 17, 2004 Mail this to a friend!
Interesting subject Steve.
From my experiences, a good RF ground will help the harmonic attenuation of any low-pass filtering being used. A low-pass filter will most effectively attenuate the harmonics if it's connected to a broadband low impedance ground. A spectrum analyzer and 'neighbors' have shown this to true for me. I use an external low-pass filter just inside the house which allows a 3ft. run to earth ground.
 
Station Grounding  
by WA2JJH on August 17, 2004 Mail this to a friend!
Yes, I do operate my Yeasu FT-100D with no station ground at all..I do use a very well isolated switching supply.

My Commercial HARRIS no problems either.

However when I use my TR-7 and TS-850, I did notice QRN and general noise level went down when I grounded everything to a thick copper wire common ground.
My ground loop problem went away, my antenna tuner would tune up faster too.(it was a POS MFJ) My Drake tuners have no such problem.

However for high power commercial apps the FCC and station engineers have thier protocols for installation.

The only lightening protection I liked,were the external ones that are at the antenna's feed point. The best one I have seen used spark gap. A stud allowed one to add a wire going to low resistance path for the lightening. I used a vent pipe.

This device ws made by Lafyette radio electronics.
(RIP)


I have a NOAA alert in one of my FRS radio's. Maybe I will mod one to diconnect my antenna. I have found when the NOAA goes off, lightening storms come 45 seconds later or so.

The Yeasu has a plastic mic. The D-104's are famous for RF lip burns!


 
Station Grounding  
by W3DCG on August 17, 2004 Mail this to a friend!
What about some of us less fortunate types who for whatever reason, might need to use a non resonant antenna on some bands, and a tuner? I know I'd like to have a current fed situation for every band, but it's not really happening in practice. Or maybe it's a multiband wire like a G5RV operating WARC, and we can use one wire, maybe if we're lucky, get 3 antennas up, but I'm optimizing one of the three to work best on an East West path for 40m, one optimized for 20m, and a non resonant catch all other wire that might not work as well as the others in some cases, but may well work better than the others in the nulls, etc.

Might you recommend an "RF Ground" for the tuner in such cases and what recommendations are they?

Should we connect the rig to the tuner ground, or leave it alone and not connect the rig to the grounded tuner? Or, should we not "ground" or run counterpoise "RF grounds" or whatever, at the tuner, at all? Should we even bother with a ground rod as close as possible to the tuner if we're not going to to deal with RF grounding at all, and just "fix" our computer from going bug nuts sometimes with RF Chokes, or by forcing current feeds via traps, etc.

Hope this helps some people, and thanks for answering, if ya'll do.

73.

Darin.
 
RE: Station Grounding  
by KA0GKT on August 17, 2004 Mail this to a friend!
Station grounding, a controversial topic.

All commercial broadcast stations have good grounds tied to their transmitters, and I'm not talking about only on the standare AM broadcast band. I just installed a UHF DTV station and everything is bonded to a common ground via 6" wide Cu strap.

Just because someone has never grounded their station and hasn't been at the receiving end of a lightning strike isn't a good reason not to ground. I know of old timers who regularly operate their HF Linear amplifiers with the safetys jumpered and the cases off. They are still alive...however all it takes is once.

Part of the rules and regulations of the FCC state that in the amateur service, in the absence of a specific rule or regulation good amateur and Engineering practices are to be observed. That includes grounding your station to a good RF, 60-cycle and DC ground (or as good a ground as is possible under the circumstances)

My station is grounded via a 2" wide Cu Strap to several ground stakes in my yard, three of which are active grounds made up of 10'of 2" Cu pipe in a post hole filed with Bentonite Clay and Epsom Salt. Grounds in Tucson are really rotten.

73 es keep yourself well grounded in Amateur Radio Theory (Bad pun Intended)

de KA0GKT/7
 
RE: Station Grounding  
by W8JI on August 17, 2004 Mail this to a friend!
by W3DCG on August 17, 2004 Mail this to a friend!
What about some of us less fortunate types who for whatever reason, might need to use a non resonant antenna on some bands, and a tuner? I know I'd like to have a current fed situation for every band, but it's not really happening in practice. Or maybe it's a multiband wire like a G5RV operating WARC, and we can use one wire, maybe if we're lucky, get 3 antennas up, but I'm optimizing one of the three to work best on an East West path for 40m, one optimized for 20m, and a non resonant catch all other wire that might not work as well as the others in some cases, but may well work better than the others in the nulls, etc.>>>>

Resonance and SWR has NOTHING to do with needing an RF ground.

Grounds have NOTHING to do with harmonic suppression of filters.

The only reason why anyone has RF in the shack is they have an imbalance issue with antenna systems, or the antenna is too close to the house and directly radiating into the house.

For example an open shield connection, a dipole fed without a balun, a poor balun in a tuner, a vertical like a Gap or IMax 2000 or even a 5BTV with a poor ground system....all cause RF in the shack.

None of it has to do with resonance or SWR.

As for harmonic suppression, if you have harmonic RF energy OUTSIDE the coax feeding the TVI filter you have serious wiring or design problems in equipment.

TVI lowpass filters simply act as a short shunting the shield to the center in the transmission line, and an open in the series path for the center. They do not divert or send RF to the outside of the filter box or the shield of the coax. If they do, the filter is very poorly made.

You DO need a station safety ground for faults or problems in equipment. EVERY cable entering the house should be grounded at the entrance point to the SAME ground the power line ground uses. That is code.

The station should also be grounded to that point, that is just common sense. A RF ground is only needed as a band-aid for other more serious problems. A common point ground in the station is a VERY good idea.

If Steve had followed these basic rules, the cable inside his house would never had passed current from the fallen line.

As a second thought, I doubt it was the 7200V hot line that was grounded to the antenna. A 7200 volt line will vaporize or eat a hole in whatever it hits. It will blow a hole in pavement in seconds, and eat it's way through thick concrete in a matter of minutes. The Yagi and feedline would have both been history, and Steve would likely be dead if he touched the amplifier case or cables while the line was connected. More than likely it was a 120V lead or perhaps a HV ground return lead that lost it's connection and fell.

A friend of mine had a balloon antenna blow into a 7200V line, and all that was left of his radios was a pile of melted plastic and charred boards. His headphones melted, and the curtains were burned off the wall where the feedline came inside. He also did not have grounds at the feedline entrance.

Let's be safe people!! Some of this stuff can get people killed.

73 Tom
 
RE: Station Grounding  
by AA4PB on August 17, 2004 Mail this to a friend!
Steve, are you saying that the towers on the Empire State Building have no grounding connections? Certainly they are not effective RF grounds due to the length of the run. Every building mounted tower I've dealt with however had a pretty heafty ground wire from the tower down to the building grounding system for lightning protection.

One issue to consider, other than a direct lightning hit, is that more often nearby strikes can magnetically induce currents into the coax runs.

I had a nearby strike that induced enough current into my home's alarm wiring to weld the contacts on all of magnetic switches and fry the controller. The rig and antennas were untouched even though everything was connected and plugged in. I have the tower well grounded as well as all the coax shields and arc-plugs at a building entrance grounding panel. I also have the ground panel connected to the electrical service entrance ground. Lightning is not very predictable so there is no way to prove that the grounding made any difference. My idea however is to attempt to minimize the odds of damage.
 
RE: Station Grounding  
by K0QX on August 17, 2004 Mail this to a friend!
>>de W8JI: As for harmonic suppression, if you have harmonic RF energy OUTSIDE the coax feeding the TVI filter you have serious wiring or design problems in equipment.>>

That's pretty obvious.

>>de W8JI: TVI lowpass filters simply act as a short shunting the shield to the center in the transmission line, and an open in the series path for the center. They do not divert or send RF to the outside of the filter box or the shield of the coax. If they do, the filter is very poorly made.>>

You're saying that filters only 'send RF' to the center conductor?

>>de W8JI: the antenna is too close to the house and directly radiating into the house>>

When harmonics are present on the center conductor of a coax, what is your definition of 'too close to the house'?
 
RE: Station Grounding  
by NL7W on August 17, 2004 Mail this to a friend!
Hello. I am sure that AM/FM broadcast radio systems use the Empire State Bldg's metal superstructure as the single point ground reference (or other multi-story, metal framed bldgs). This would be the prudent and effective ground. All bldg grounds would most likely reference this metal superstructure at and above ground level. 73.
 
Station Grounding  
by W4UDX on August 17, 2004 Mail this to a friend!
KE4MOB:

My antenna tower is very much grounded at the base where it should be. This is the best method.... keep your grounds outside. My tribanded is grounded to it by design. If lightning hits, it will go straight down the tower and into the ground - the shortest path with least resistance. It's also the path that can handle the most voltage and current.

Would you have me leave my coaxes connected during a storm? Or trust some "static discharge unit". Are my RG-58X coaxes when connected to my radio gear a better ground path for lightning than the tower? Even if grounded by some "ground bus"? Do what you want with your gear, but I am not going to leave mine connected to a grounded tower and hope for the best. Nor will I hope some so-called ground strap will sufficiently divert any lightning blow-by to the ground.
I have been using my method for years, and my tower has been hit in the past, and no... there was no shrapnel from the jar....
 
RE: Station Grounding  
by W6TH on August 17, 2004 Mail this to a friend!


No matter what, I am keeping my complete station fully grounded, each and every piece of gear. Been doing this since day one and am not making the change now as all has been fine with me and my radios.

I can take my center fed zepp and go from 160 to 10 meters and not a bit of rf traceable. Even using my D-104 microphone.

My Pi-network on all my amplifiers and amplitude modulated radios tune from 50 to 600 ohm impedance and are a perfect match for my halfwave resonant antenna with a single wire feed, which is tapped off center for 600 ohms impedance.

Have it your way and you have that right, let freedom ring.

.: W6TH
 
RE: Station Grounding  
by KC8YVE on August 17, 2004 Mail this to a friend!
HI HI Dave.

I can say nothing but Ditto!

God Bless.
Tracy
 
RE: Station Grounding  
by KC8YVE on August 17, 2004 Mail this to a friend!
HI HI Dave.

I can say nothing but Ditto!

God Bless.
Tracy
 
Earthing, You Earthling  
by KA4KOE on August 17, 2004 Mail this to a friend!
Its always good practice to make sure you are well grounded in the basics of bonding items together.

Doing otherwise is grounds for an electrocution.

You should begin your installation from the ground up.

If Charles VWM is at a hazard for an electrical shock, then ground chuck.

Groundings usually take place when the young exceed their preset limitations by localized adult authority figures.

Sucess in ham radio is, as quoted from my friend WN9V, 25 years at it without one fatal electrocution.

Elocution is something completely different. Ask Cal, K4JSR for guidance on this one.

Putting things together that are different will corrode the general state of affairs.

He who is selfish with the sledgehammer during an installation is a ground hog.

He who sits up front and only pays a pittance to witness a performance is a groundling.

Inserting a bonding conductor inside a round, plastic toy will result in a ground loop.

See 2002 Edition for further revisions to Grounding and Bonding of various installations.

PHILIP
 
RE: Station Grounding  
by AA4PB on August 17, 2004 Mail this to a friend!
It is fine to disconnect your coaxes from the radio if you can do that. If the coaxes are not grounded just outside the entrance point however, and the tower gets hit (or voltages induced into the coaxes by a nearby strike) then you bring the high voltage right inside your house. You may have an arc between the end of the coax and some other ground in the house. If on the other hand you have a good ground at the house end of the coax then much of the energy is disipated in the coax run and the end inside the house does not rise to such a high voltage. Even though the tower itself is well grounded, any ground has some resistance (and inductance) and if the current is high the tower base can still rise to some very high voltage. The entrance ground gives you another chance to minimize the voltage inside the house.

The "static discharge" unit may prevent a voltage from building up between the center conductor and the shield which might prevent damage to a connected radio. It probably will not help if you take a direct hit but again the idea is to improve your odds.

I generally disconnect the HF stuff when not in use but the packet station runs 24/7 and cannot be disconnected.
 
RE: Station Grounding  
by AL2I on August 17, 2004 Mail this to a friend!
Steve: After reading through this thread, I suddenly realized that I am a special test case with something I am doing now. I am helping to build a multi-multi club station on the North Slope of Alaska, and our Ham shack is a 60' trailer on rubber wheels that is powered with a 50' cable to a connector on the ouside of the trailer. We have four ham rigs, three small towers which will get a ground through the metal structures they are attached to, but no earth ground for the shack or anything in it, including a small tower that will attach only to the trailer.

The trailer sits on a 5' deep, dry gravel pad, and the Earth ground under that is known for its poor conductivity (permafrost). As we build this station, we are simply plugging everything in, connecting coax, bandpass filters, rigs, tuners, coax switches, antennas, etc. The only ground is through the connectorized power cable because even the coax shields going to the grounded towers are not themselves grounded anywhere.

Is there any special consideration I should think about. I see that you and some folks contributing to this thread have extremely deep knowledge and experience, and this is something that is outside my experience: a *sort of* grounded shack.

I've been in cars and boats and planes with no grounds at all, but is there some filtering that should go on the power connector when that is the only ground to the structure? We rarely get lightening, but it has happened. Our ungrounded coax leading in to the shack as well as the shack itself could pick up some induction, and the path out would be through the power cable.

73 and thanks in advance for any advice!
-Dave/al2i
 
RE: Station Grounding  
by WB2WIK on August 17, 2004 Mail this to a friend!
Gosh, a few things to reply to here:

Tom, it was indeed a 7200V line. It was up 80' above ground (not the normal 30' or so for 240v lines) and the utility provider verified this was a 7200V "primary" line they had to replace; the break was at the insulator for the local pole pig that provided service to our four homes. It didn't blow a hole in anything. Obviously, not enough Joules! Possibly a primary line from the substation would have done a whole lot more damage, but we were pretty far from the substation, and this was an ordinary residential service line for four homes, feeding a single pole pig transformer down to 240V.

The learning experience is: Don't ever place antennas under 7200V lines, as unlikely as they are to break -- they do break, occasionally.

As for the Empire State Building, remember the antenna tower installation there is 60 years old and the transmitters are located nearly 1000 feet above the street; the antennas are 1200' above the street. The steel structure of the building is not a great ground, although it's certainly grounded at the base, repeatedly, since the building is one city block square.

We used to refer to "ground" up there with a bit of a laugh. Ground up there is a common return path for many things, but it's very, very far above earth and the impedance to earth at even 1 MHz makes it useless. At VHF FM-TV BC frequencies, it would be laughable.

The roof of Empire is grounded not only by the building's structure, but by four large (stranded) copper cables running down all four corners of the building. I'd guess they were about #0000 gauge. Still, not nearly sufficient for a real ground when they're >1000' long. And prudence learned since those days (the 1930's) would dictate the use of smooth, solid conductors, not stranded ones, for a more effective ground. What they didn't know evidently didn't hurt them.

WB2WIK/6

 
RE: Station Grounding  
by AA4PB on August 17, 2004 Mail this to a friend!
Are my RG-58X coaxes when connected to my radio gear a better ground path for lightning than the tower?
-------------------------------------------
No, but they are a ground path. Ohms law says that the current will divide between two parallel paths. Most of the current will flow into the low resistance ground at the tower base BUT some will flow thru the coaxes into the shack to the radio gear. By grounding the coaxes at the entrance you provide an additional low resistance path outside of the house. The energy can be disipated in the resistance and inductance of the coaxes thereby minimizing the current flow thru the radio gear and any other grounds (such as electrical service ground) that may be connected to the radio.
 
Station Grounding  
by K0ZN on August 17, 2004 Mail this to a friend!

Hi, Steve,

Certainly, you put a lot of thought into that. I certainly have to give you credit for effort and for provoking some thought and conversation!

My only "concern" about your comments is that there may be some people with less technical UNDERSTANDING of SYSTEMS than you have who may come to the conclusion that grounding is unnecessary under any conditions, which can be literally dangerous.

I will say up-front that I am a member of the
"pro-grounding" Party. My allegiance is based on:

1.) EVERY communications system/radio station that involves THE SAVING OF LIVES (military, marine, aviation, public service, etc. etc.) as well as all commercial communications systems go to GREAT lengths to get good grounding and equipment bonding.

2.) I have personal professional experience with military HF & VHF communications systems and telephone company equipment. I have seen MANY times where excellent grounding has either minimized or PREVEVENTED damage due to lightning and/or static build up AND has reduced noise levels in systems.
I have personally witnessed several telephone and radio system installations where signal to noise was MEASUREABLY improved when the ground system and bonding was improved.

3.) I live in a very high lightning hazard area in eastern Kansas. We get some incredible lightning events from thunderstorms during the summer months. MOST of my old time ham friends have been hit to some degree over the years and those with "excellent" grounding and equipment bonding usually survive strikes. I have heard a LOT of first hand stories about poorly grounded stations being damaged by incidental nearby surges.

4.) Lightning is HIGHLY UNpredictable, even with good grounding. It can hit and enter a building from multiple sources and damage electronic equipment. EVEN IF YOU DISCONNECT AND PULL COAX OR PARALLEL LINE OUTDOORS, lightning can STILL (I have seen this!) come in via a telephone drop, cable TV or AC power drop
( YES, even underground) and do severe damage to IMPROPERLY grounded and bonded electronic equipment.

5.) I have been a Ham since 1959 and I have "been there and done that" when it comes to lightning. I have also heard a ton of lightning "war stories" over the years. I am a true believer when it comes to grounding.

I agree that an improperly designed and fed antenna and transmission line will "create" the need for a good RF ground, but the flip side is, having an excellent ground system will NEVER hurt a station or antenna system, and it can add to the flexibility of POSSIBLE antenna systems that can be used at a given station location.

Over many years, and as a result of a LOT pragmatic experiences in many locations of the world and various situations, the U.S.Army Signal Corp has developed some pretty standard equipment grounding practices. From what I witnessed, I think it would be pretty presumptous of the average ham to conclude that he had broader experience, knowledge and long term data than the Army Signal Corp had developed and presume that grounding was unnecessary. (You could also include the telephone companies and others in the professional communications industry in this too...)

I'll second what a crusty and knowledgeable old sergeant once said to me: "You CAN'T have too much ground...."

Thanks again for the article. You did make people sit up and think!

73, K0ZN
 
RE: Station Grounding  
by K3ESE on August 17, 2004 Mail this to a friend!
The Teaberry Shuffle!
 
Grounding aids  
by KA4KOE on August 17, 2004 Mail this to a friend!
There is practical real world experience with enhancement of ground rod conductivity with electrolytic solutions, ie saline and other compounds.
If salt isn't handy, just pop open a can of beer. Drink half, and in true Greek offering fashion, offer up the other half to the radio gods and pour the other half over the ground rod.

Colt 45 size, Malt Liquor, is a particularly good performer in this respect, ie enhancement of conductivity. Its also a good performer in the inebriation department as well.

Personally, I prefer Guinness.
 
RE: Station Grounding  
by N1VLQ on August 17, 2004 Mail this to a friend!
Wonderful article, Steve. As usual, you are most informative.

It also helps me get past that pesky project that I've been meaning to do for some time now, but since my shack is in the basement I've always put it off. Guess I'm all set now, like I was already!

One thing that I thought I might add to the discussion on UL and NEC.... if I remember correctly, Astron power supplies are not UL rated. Never submitted them to UL, as I understand it. For whatever reason. Yet how many hams swear by their Astron supplies....must be breaking the law, according to some here. Or at least the insurance companies policies!
 
RE: Station Grounding  
by KE4MOB on August 18, 2004 Mail this to a friend!
>>>Would you have me leave my coaxes connected during a storm?

Yes and no. I disconnect mine from the radio and connect them to a ground bus that bridges both center conductor and shield to ground. It consists of bulkhead SO-239s mounted in 3/8" thick steel bar, with center conductor shorted to ground. Anything coming down the feedline (either shield or center conductor) isn't given a chance to "jump the air gap". It goes to ground.

>>Or trust some "static discharge unit".

I'd rather trust a Polyphaser than a Mason jar.

Mason jars are for pickles, not lightning protection.

 
RE: Grounding aids  
by KE4MOB on August 18, 2004 Mail this to a friend!
>>There is practical real world experience with
>>enhancement of ground rod conductivity with
>>electrolytic solutions, ie saline and other
>>compounds.
>>If salt isn't handy, just pop open a can of beer.
>>Drink half, and in true Greek offering fashion,
>>offer up the other half to the radio gods and pour
>>the other half over the ground rod.

I would think that a better electrolytic solution could be obtained by drinking the whole beer, waiting 30 minutes until the kidneys kick in and......nevermind.
 
RE: Grounding aids  
by K6AER on August 18, 2004 Mail this to a friend!
Steve,

Great thought provoking article but I must take exception to your premise about lightning protection and grounding not being necessary. You should live in the Midwest. K0ZG has a better perspective regarding lightning protection of your ham station. As you know I live in Colorado and have been hit by lightning almost twice year. In my 4 years out here I have been hit seven times. We live in an area that has three months of lightning storms every day. This year I have been hit twice and still I have not lost any equipment.

I have adopted commercial lightning standards for my home which is the same as my company, Sprint uses on their Cell tower installation. Bonding all your ground fields together is necessary to reduce induced inductive coupling and different potential fields. Also you surge protection must be held at the ground halo point and be kept a close to the ground field to reduce RF resonance in ground lengths.

Most surge problems come in via the AC panel. Lightning hits a power line and the surge is transmitted via the power grid. Ninety-five percent of all home lightning damage is via the AC panel and grid induced surges. Almost all residential electrical panels have inadequate grounding and as a result are worthless for lightning surge potential. The NEC code requires only a single ground rod for if the ground resistance is under 25 ohms. I have never come across a home with more than one ground rod. Unfortunately this is not good enough. A good ground system for lightning should be below 2 ohms ground resistance. As you can see your electrical panel might be OK for a lost return (neutral) ground but will not be able to handle a lightning surge. Every electrical panel should have surge protection. Without some kind of surge protection in the panel, a lightning surge will try to find a path thorough your AC wiring via all the appliances and electronics in your home.

Your statement regarding Noise and grounding is true to a certain extent. Good grounding will not reduce atmospheric noise. It will reduce AC induced surge noise and glitches.

I must be noted that what most hams do not understand is lightning is made up of two components, the DC surge and the RF component. Each is handled differently. The DC component is easier. The RF component has to be approached as an impedance problem. A typical lightning strike is over 20,000 KW of RF in the strike covering from 2-60 MHz. This is why we hear lighting on the radio so far away. Keeping your ground leads to the ground field as short as possible will reduce the RF component. Grounding your coax lines and using RF surge protectors at the base of the tower will reduce the coax center lead potential. Proper grounding of a residence for lightning is a bit of a problem for a home owner in the Midwest. A home residence was not designed as a commercial transmit facility as a result the grounding task is much more difficult, but it can be done. The combined ground field around my home is below .4 ohms. As a result when I take a strike my ground field voltages are low enough to prevent equipment damage.

As always keep up the good work.

73’s

Mike - K6AER
 
RE: Station Grounding  
by K9KJM on August 18, 2004 Mail this to a friend!
Another very well written article!
And I cannot disagree with any part of it.

All of the little "ground" thumbscrews on the back of all of my radios are also not connected to anything.
(30 years ago, It was poplular to still connect them to a ground, thereby creating the daisy-chain ground loop problems mentioned) But nowadays the "single Point" ground where coax enters the shack is the way to go.
This is the lightning protection ground system that WIK's article unfortunatly simply dismisses.........

For good information on PROPER lightning protection
grounding, See the tech notes at:

http://www.polyphaser.com/ppc_pen_home.asp



 
RE: Station Grounding  
by AE6IP on August 18, 2004 Mail this to a friend!
> if I remember correctly, Astron power supplies are
> not UL rated. Never submitted them to UL, as I
> understand it.

Alas, like so much one reads in this thread, this is not correct.

 
RE: Station Grounding  
by W8JI on August 18, 2004 Mail this to a friend!
We also seem to have some Ohm's Law issues here, or an oversight about about how systems work. From the article:

"No matter how you cut it, your stuff is grounded (if you have an engineered installation), like it or not. So, the “safety ground” consideration, to prevent electrical shock in the event of internal equipment malfunction, is very likely covered. A 1 Ohm connection to earth will keep a 120v line down to 15v before it trips the 15A circuit breaker or fuse in a conventional household circuit. You won't feel the 15 volts."

Factually a one ohm to ground connection on a 120 (or 240V) USA single phase line will result in 120 amperes, and the voltage across that resistance will be 120 volts if the line feeding that point has zero ohms.

Circuit breakers and fuses DO NOT limit current to 15A as the article implies.

Current is limited by the SYSTEM impedance, voltage drop through the breaker or fuse can be considered to be near zero.

There is a finite amount of time taken for a breaker or fuse to open, and that is the time we have to worry about. It can be many seconds or minutes for minor overloads of a hundred percent.

In fact, we have no way of know what the voltage in the case outlined in the article would be becuase we don't know the ESR of the line and system feeding that point, but I would bet money it is a **lot** higher than 15 volts. 15 volts would require the line from the transformer into the house and room have 105 ohms of resistance, something we can be sure is not even close to correct!!!

The same rules apply to dropping a 7200V primary to earth. You can bet the path resistance, even dozens of miles from a substation, is tens of ohms or less. Beyond that and the line would almost certainly fall out of regulation limits and the utility would be in trouble. Say it is an extreme case and loop resistance is 20 ohms.

7200/20 = 360 amperes. Good luck on not having a house fire! Whoever said that was a hot primary was either misunderstood or wrong.

Ohm's law works, and is why power line fault voltage will be MORE than 15 volts in the example and why if a 7200V primary actually hit an antenna on a tower the antenna and anything attached to the antenna or tower would be history. Welders use less current, and have substantially less voltage.

Let's not endorse poor shack safety with misuse of Ohm's law or misunderstanding of how components like circuit breakers work. Anyone who does not have an independent safety ground that is bonded back to the power line entrance ground from his Hamshack is not being safe. Depending on the antennas for that ground is being both foolish and unsafe.

73 Tom
 
Station Grounding  
by WA2JJH on August 18, 2004 Mail this to a friend!
Even your toaster and blender are UL tested/rated
 
RE: Station Grounding  
by W9PMZ on August 18, 2004 Mail this to a friend!
A person who I once knew in Florissant, Missouri, installed his antennas near a 7200V transmission line.

One evening during a storm blew the antenna or the cable into each other (this was 16 years ago and I don't remember that part).

But, the antenna cable in his shack vaporized at the radio and the cable proceeded to fly around the room starting fires.

The only thing that save his house was the fact that his shack was in the basement. The cable hit a copper water pipe, of course vaporizing part of the pipe and putting out the fires.

This could be an urban legend, the they guy swore it happened (he didn't live to far awary and I can attest for the power lines).

How would proper grounding have saved this individual from his unfortunate placement of antenna?

Carl - W9PMZ
 
RE: Station Grounding  
by W8JI on August 18, 2004 Mail this to a friend!
by W9PMZ on August 18, 2004 Mail this to a friend!
A person who I once knew in Florissant, Missouri, installed his antennas near a 7200V transmission line.
SNIP
The only thing that save his house was the fact that his shack was in the basement. The cable hit a copper water pipe, of course vaporizing part of the pipe and putting out the fires.>>>

That damage sounds like what a 7200V line would do.

<<How would proper grounding have saved this individual from his unfortunate placement of antenna?>>>

Here is the point:

If the cables come into the house properly and follow national electrical codes, they would be grounded at the entrance to a good ground that ties back to the service entrance ground. This bypasses the house INTERNAL wiring and equipment for most fault currents.

The internal shack ground is required for electrical safety. Ham equipment is not required to have UL approvial or meet any safety standards. Designs I did for Heathkit, for example, followed UL construction guidelines but ONLY for liability reasons. Amateur equipment was never submitted or tested for compliance.

Heath was one of the only companies I know of that even followed guidelines, and only then around power line connections.

Odds are that many pieces of gear in your shack do not have large amounts of headroom for arc-path distances and insulation between power line wiring and even HV wiring. Even if it does, something can still go wrong.

We absolutely NEVER should defeat or remove a ground connection as some have suggested, and equipment should have the grounds all grounded to a common buss that eventually also finds a secure and reliable path back to the service entrance ground.

This isn't to save you from a 7200 primary line laying on an antenna (which I guarantee will ALWAYS vaporize something to open the circuit, and probably start a fire in the process), but it will save you from secondary 120V to ground faults or even save most equipment from loose cable connections or open RF shields.

I strongy believe this is what Steve had because a 120V fault would make things heat and hum and not necessarily vaporize things or start fires. A 120V fault could indeed sit there for hours while waiting for a line crew.

A very old church down the road (that has knob and post wiring) is fed with a long open wire 120V line. That line dropped onto one of my antenna ground systems and eventually after a long time opened the transformer overload on a 5kVa transformer. It was about 500 feet of number six or eight wire, plus the resistance of the path from the ground back through the coax to my entrance ground.

I never would have knew it was happening except it started a grass fire from heating up some radials.

Had the cables entered my shack without a bulkhead ground tied back with flashing to the power line entrance ground, you can bet things inside the shack would have hummed and perhaps even gotten a bit warm.

There are layers of protection we need, and the same things that prevent or reduce lightning damage protect us from other high voltages finding the major path through the house. That is the entrance grounding. We all need this ground.

The ground in the shack is for equipment fault protection. Line operated or high power RF Ham equipment needs that ground.

There isn't a single valid reason to do something like cut ground pins off cords or intentionally isolate grounds, or to not common ground equipment at our operating positions.

73 Tom
 
RE: Station Grounding  
by N1VLQ on August 18, 2004 Mail this to a friend!
Ahhh, I see. I must have the only Astron power supply without the UL lable on it, then.

(I did say, "if I remember correctly", thus allowing the extreme chance of being incorrect. My apologies for offending y'all with my inaccuracies. GRIN)

After all that, I had to check my Astron. PLEASE correct me, as lord knows I need the help, but if a product is UL Listed, it will be indicated as such somewhere on the case, correct? Not simply in it's owners manual. Somewhere on the case.

Nowhere on my RS20A is there a UL listing noted.

(I didn't check my toaster and I don't have a blender. Will it tune on twenty?)

The reason I pointed this out was that the company I work for used to sell car stereos. We had a displayer, with many models set up, all powered by an Astron RS20A (hhhmmmmm coincidence?). We used to order those RS20A's from our supplies department, to sell to customers, like hams, CBers, marine radio operators, etc. Suddenly, we weren't allowed to get those supplies any more. While no "official" explanation was offered, I was told by someone at our corporate headquarters that they discovered that those supplies weren't UL listed, and didn't want us selling them as a result of that discovery.

And that might be all a bunch of hooey, too.

I still enjoyed the article, and the fact that I have further justification not to try and concoct a way to get a dedicated ground lead out of my shack. If I ever have my shack configured differently, or I were to move to an area that is hit more by lightning, or I hang more metal, especially a tower.... well, maybe I'll approach it differently then. But my little basic station, with a small HF vertical and a dipole, and the radio's in the basement, I'll try it Steve's way. With my thanks!

Take care, folks, and HAVE FUN.

 
RE: Station Grounding  
by WA1RNE on August 18, 2004 Mail this to a friend!

We could ask the question another way:

What would have saved the guy who installed his antennas near a 115 KV transmission line?

Answer: a massive injection of common sense.

This is obviously an extreme case in comparison to what usually occurs on a daily basis in different locations and climates.

The bottom line is, Amateurs should build their stations in accordance with good practices - and in this case, a decent station ground helps do exactly that because it:

*Is good insurance against antenna intangibles for the vast majority of hams;

*Protects gear from moderate fields generated from lightning discharges for the vast majority of hams. ***Notice I said moderate - not a direct hit.

*IS CHEAP.

Seems to fit most amateur's criteria, yes??


 
RE: Station Grounding  
by K3UD on August 18, 2004 Mail this to a friend!
I started to re-think this when my entire shack was destroyed by a lightning strike on the opposite side of the house from my tower. I had, what I thought to be a good station ground in the usual sense of the word. Each leg of the tower grounder and several 8 foot ground rods just outside the shack , tied together and a single ground wire coming into the shack forming a bus that attached to all equipment.

When the lightning hit, evidence shows it somehow came down the ductwork of the heating /cooling system under the house and found my station ground.

Everything but the ground bus was disconnected and unplugged as is usual when storms are predicted. The lightning must have come up to the shack through the ground as the bus wire was melted between the radios and the ground wire to the ground rods was melted in several places.

73
George
K3UD
 
RE: Station Grounding  
by WB2WIK on August 18, 2004 Mail this to a friend!
Golly, too much stuff to read through at this early hour -- COFFEE...!

Mike (K6AER), nowhere did I say grounding was a bad idea, and I tried not to discuss "lightning protection" grounding, at all. My strong feeling is that lightning protection grounding is all *outside* the home, and has nothing to do with the little screw terminal on the back of ham equipment chassis. That's pretty much all I've been saying, throughout the article.

Forget about the midwest, I've lived in Florida, which is the lightning capital of North America, if not the world. Look at any incidence map, and you'll see the lightning belt on the east coast, which maximizes in Florida, is far worse than anyplace in the midwest.

Somebody mentioned that Astron power supplies are not UL Recognized or Listed, and then others disputed that. I can set that record very straight, since I have an association there:

Astron *never* bothered to get UL product listing on any of their products for many years. I mean many, like from the beginning of the company about 30 years ago, until about two years ago. Thus, the majority of Astron power supplies we hams have in our shacks and have accumulated over decades probably do *not* bear the UL label, and they shouldn't.

Recently, Astron *did* apply for product listing on many of their models, and they can now carry the UL logo. The most recent Astron advertisements do make note of this, in a banner across the tops of the ads. That banner wasn't there two years ago -- in fact, I think it wasn't there last year. It's a recent event.

This issue is often one of cost, more than anything else. UL charges per listing for the investigation, filing and authorization letter, and although you can list multiple products simultaneously, if the products are too different they cannot be part of the same project (although thousands of products can be part of the same file). At roughly $7000 per listing, for a company that has thirty products that are all sufficiently different to require separate projects, the cost would be $210,000. To maintain the listings requires an Annual Service Agreement with UL, and the payment of annual fees -- per product.

It can get pretty hefty for a small company who's trying to control costs and provide attractively priced products for the consumer.

The end of a 7200V HT line serving a 2-home cul-de-sac and installed inthe 1950s, by the way, is capable of only providing about 10A @ 7.2kV. 720 Ohms of resistance could carry that entire load current, but obviously series circuit resistance, including coincidental grounding in almost any residence would be much lower than that.

When we used to test RADAR power supplies (at Raytheon) capable of delivering 15kV at >10A and did short-circuit testing under those conditions during DVT cycle, "interesting" things resulted, but blowing connections to smithereens wasn't one of them. The most intersting event I can recall was the 3-phase power cords jerking along the floor when the short circuit was applied to the rectifier output, sometimes so severely it could trip people standing nearby. That was exciting. But contacts would not routinely weld nor blow open.

Although my incident occurred many years ago and in New Jersey, so there's no way to re-enact the event, I think I satisfied myself that there are enough ground paths in nearly any station to sustain quite an accident. When I unplugged my amplifier from the 240v line, had that been the only ground return path, the chassis of the amplifier could have become very alive with high voltage.

It didn't, of course, because six other cables were plugged into the same antenna switch, and all those went somewhere where their shields were connected to ground, even if that meant a return path from switch to cable to tower, so the alternate path would be back outside again.

Still wouldn't recommend installing antennas where power lines can fall on them, and I've tried to avoid that over the last 20 years or so. I also try to use beams that have DC-grounded feedpoints; even on my old Hy-Gain "beta match" hairpins, I ground the center point of the hairpins to the booms. Leave all the bad stuff that can happen "outdoors" if at all possible!

WB2WIK/6
 
Station Grounding  
by W9DZ on August 18, 2004 Mail this to a friend!
Nice article Steve. In 43 years of operation I don't think I've ever brought a ground into the shack other than the grounded 3-wire AC outlets. The electrical system is connected to an 8' ground rod where it enters the house. I have two 8' ground rods connected to my Heights aluminum tower. I've never had RF floating around. Then again I don't do stuff like tieing the center conductor and shield of the coax on my 40M dipole together and try to use it on 80 or 160M as an end fed wire. We get plenty of lightning here just south of the Lake Michigan shore. I leave the coax and power leads disconnected when the station is not in use.

Allen, W9DZ
 
RE: Station Grounding  
by AA4PB on August 18, 2004 Mail this to a friend!
My strong feeling is that lightning protection grounding is all *outside* the home, and has nothing to do with the little screw terminal on the back of ham equipment chassis
----------------------------------------------
I can absolutly agree with that. I think it also agrees with what Polyphaser is recommending.
 
RE: Station Grounding  
by K1KID on August 18, 2004 Mail this to a friend!
Great article Steve. I have been preaching for years that you DON'T want to ground your antenna feed lines, especially in the house, during thunderstorms. I have tried to explain that you are putting a wonderful path to ground up at the height of your antenna, inviting a lightening stroke to surge down into your shack. You don't want anything you value to be within a thousand feet of a lightening stroke. Lightening "leaders" branch of in many unpredictable directions creating collateral damage as well. I believe in letting the coax ends float as in the previous mason jar example.

The other concepts that are sometimes impossible to get others to accept: A high SWR does NOT mean that an antenna is NOT working well, and a low SWR does NOT mean an antenna IS working well. The lowest SWR of any RF load I have is my dummy load and it doesn't radiate well at all.

Thanks for a very articulate discussion of a difficult subject.

Carl, K1KID
 
RE: Station Grounding  
by AA4PB on August 18, 2004 Mail this to a friend!
I have been preaching for years that you DON'T want to ground your antenna feed lines, especially in the house, during thunderstorm
-------------------------------------------
I would agree that you don't want to ground them inside the house to a long ground wire, water pipe, etc. I would disagree with the first part of that statement - "you don't want to ground your antenna feed lines".

Standard commercial practice calls for them to be grounded at the tower base and at the outside where they enter the house. Of course if the tower is mounted right next to the house then one single point ground at the base is probably all you can do. If the tower is located say 30-feet from the house then you need two grounds; one at the tower base and one single point ground at the house entrance.

The fact is that the tower is sticking up there and succeptible to being hit by lightning regardless of whether you ground it or not. I don't believe that grounding the tower is going to make it more likely to get hit. If it does get hit, then the goal is to minimize the voltages on the coaxes coming into the house and that means a ground. Now if the tower is located 30 feet from the house and you want to disconnect all the coaxes, rotor lines, etc. and carry them out to the tower (away from the house) any time you are not on the air then that's fine. I'll bet that most people don't do that however. They disconnect them and leave them lay on the floor and think they are safe from lightning. In this area (VA) thunderstorms can appear very quickly and without notice. Sometimes there is lightning well ahead of the storm. It is difficult to ensure that everything is always disconnected and moved out to the tower before the lightning. Of course if the tower is not grounded either then the lightning will likely flow thru the concrete base on its way to ground and may damage the base.

I'd highly recommend that anyone go read the amateur antenna grounding information on the Polyphaser web site at http://www.polyphaser.com/ppc_PEN1016.asp before deciding to follow advise not to provide any lightning grounds.
 
RE: Station Grounding  
by W8JI on August 18, 2004 Mail this to a friend!
RE: Station Grounding Reply
by WB2WIK on August 18, 2004 Mail this to a friend!
The end of a 7200V HT line serving a 2-home cul-de-sac and installed inthe 1950s, by the way, is capable of only providing about 10A @ 7.2kV. 720 Ohms of resistance could carry that entire load current, but obviously series circuit resistance, including coincidental grounding in almost any residence would be much lower than that<<<<<

Nope, that's a violation of Ohm's Law again Steve.

720 ohms at 10A would drop 7200V, so there would be ZERO voltage left to run your house. The power company would be wasting 72Kw as heat someplace. It isn't going to happen!

720 ohms at 5A would mean your line voltage with PERFECT power factor (which never happens) would be 60 volts instead of 120. That isn't going to happen either. At 1A, much less than a normal single family home uses, voltage drop would be OVER 720 volts or over 10%. No way that's going to happen either.

I'll guarantee you without a doubt the power line primary ESR is in the very low ten's of ohms or less.

For example, 20 ohms loop ESR would mean a full load of 20 KVA with perfect power factor (something that never happens, so the real case would be WORSE drop) would have 2.78A * 20= 56 volts sag.

3/4% sag in primary voltage from losses is acceptable. Fault current would be 7200/20=360 Amperes in that case.

I'm afraid of you run the numbers on this, the fault current is ALWAYS many times the useful peak load current. No way around that.

There isn't any possible way that was a primary laying on your antenna with the result you described, I don't care what the power line employee told you. If it was a primary, your cables and radios would have vanished in a big flash.

73 Tom
 
RE: Station Grounding  
by KC8VWM on August 18, 2004 Mail this to a friend!

The way I figure it is.. Public Service emergency dispatch centers ground everything "inside" the building to protect millions of dollars worth of radio dispatch equipment.

Perhaps, if someone would have told them the truth about all this and suggested that they only need a Mason Jar.


73

Charles - KC8VWM
 
Station Grounding  
by WA2JJH on August 18, 2004 Mail this to a friend!
Yes, many a rig I just hooked up a power supply, tuner and ant.

Had no problems.


More complicated shacks can experience ground loop problems.

Many devices, long AC cable runs, and using NON grounded outlets from different breaker feeds.

Just ask the dude that plugged in his guitar in one amp at one end of the stage. He then did the old whammy trick on a microphone stand! The microphone was plugged into an AMP at the other end of the stage.

I forgot if he died or the electric guitar strings lite up like nichrome wire in a toaster!!!!
 
Station Grounding  
by W4VR on August 18, 2004 Mail this to a friend!
I did not ground my equipment for 35 years out of 42 years and never had a problem with RFI or lightning. After taking a course in grounding at George Washington University I decided to ground my equipment...during those seven years I have been hit by lightning 3 times and have incurred tremendous losses as a result even though the insurance companies picked up the tab on some of the equipment that was damaged. So, is it bad luck or does grounding everything attract even more lightning???
 
RE: Station Grounding  
by WB2WIK on August 18, 2004 Mail this to a friend!
W4VR, I guess that really is the question, and I haven't the foggiest idea what the answer is.

Polyphaser et al. and various "lightning institutes" would certainly have you believe that excellent grounding, along with the use of many suggested products, is helpful.

My examples include the one of the Empire State Building, which for almost 40 years was the tallest building in America and has had a huge transmitting tower atop it for more than 60 years now, and was 100% designed and built way before all the "lightning institutes" existed or any studies were available, doesn't suffer any equipment damage from lightning. Everything up there is so far above ground it's incredible. Modern protection devices didn't exist when it was all built. A miracle of not-so-modern science.

I'm afraid to add much grounding to my station, since, like you, I've operated from many locations for about four decades without sustaining any lightning damage or experiencing even a single "lightning event." If I start adding grounds now, my luck might change.

But this article was never intended to be about that, anyway. I was trying to focus on the little screw terminal on the chassis of most ham gear, and why nobody needs to connect anything to it -- usually.

WB2WIK/6

 
RE: Station Grounding  
by W6TH on August 18, 2004 Mail this to a friend!


Very strange as who is right and who is wrong on lightning strikes.

My tower is at 65 feet, I have had lightning strikes within 150 feet of the tower and started a fire that burned 2 1/2 acres. The tower is mounted on a 4X4X5 foot block of concrete and not grounded, but by the concrete base mount. This is purposely done, yes my doing.

I understand that the earth is negative and the sky is positive and electron flow is from negative to positive.

When current is flowing in a wire, what is actually moving is the electrons. Electrons have negative charges. When they have the chance, electrons generally move from areas that are crowded with electrons (negative charge) to areas that don't have as many electrons (positive charge).You have probably seen current shown as going from positive to negative, which isn't how the electrons move. Inside of a battery, yes.

Remember the flow of electrons from negative to positive and that means from the ground to the sky.

Now my point: Ground or don't ground and hope for the best. To each his own and it is your right.

.: W6TH

 
RE: Station Grounding  
by AA4PB on August 18, 2004 Mail this to a friend!
I believe the clouds can be either negatively charged or positively charged with respect to earth so the electrons can flow either up or down - that is if you believe the History Channel.
 
RE: Station Grounding  
by AA4PB on August 18, 2004 Mail this to a friend!
I'll bet that the Empire State Building has some pretty heafty cables running down from the tower to the ground to provide lightning protection for those towers.

The ideas on the use of lightning rods on buildings has changed over the years. At one time the insurance companies were having the removed because they "attract" lightning. Now they are wanting them put back. Our local building codes now require them on buildings over a certain height. All this is very hard to prove or gather data on but in all likelyhood you just had bad luck with the strike after grounding. Who knows what might have happened if that strike occured before you did the grounding. On the flip side, I've had my tower grounded for 20 years and never took a hit. I've had nearby strikes that damaged other wiring in the house but didn't touch the tower or radio equipment. From that you might conclude that the grounding protected the radio equipment - or mayby I just had good luck.
 
RE: Station Grounding  
by W6TH on August 18, 2004 Mail this to a friend!


Lightning is the visible effect of a thunderstorm. It develops when rising and descending air, ice pellets and rain droplets within the thunderstorm separate into positive and negative charges. Interactions of these charged particles produce an electrical field within the cloud with the frozen upper levels of the cloud being positively charged and the lower portions negatively charged.Lightning is dangerous, so you should always follow the safety rules to avoid injury

Generally the earth has a negative charge compared to the atmosphere. As a thunderstorm passes over the ground, the negatively charged cloud base produces a positive charge on the ground below. The charge on the ground follows the storm like a shadow. The attraction between positive and negative charges makes the positive ground current flow up buildings, trees and other tall objects trying to establish a flow of current. On average, lightning produces 15 million volts of electricity, although up to 100 million volts can be generated. However, air is a poor conductor of electricity and acts to insulate the cloud and ground charges, preventing the flow of current until enormous electrical charges have built up.

.:
 
RE: Station Grounding  
by AE6IP on August 18, 2004 Mail this to a friend!
> Ahhh, I see. I must have the only Astron power
> supply without the UL lable on it, then.

Nope. Mine doesn't have a UL label on it either.

> (I did say, "if I remember correctly", thus allowing
> the extreme chance of being incorrect. My apologies
> for offending y'all with my inaccuracies. GRIN)

I hear you. A good day is one when I can remember where I put my driving glasses. No offense taken, and sorry I gave the impression that one was.

> After all that, I had to check my Astron. PLEASE
> correct me, as lord knows I need the help, but if a
> product is UL Listed, it will be indicated as such
> somewhere on the case, correct?

Underwriter's Laboratory has two levels of certification. If they test the product and it meets their requirements, it gets certified. Astron power supplies are so certified.

UL also has a "Follow-Up Service" which investigates how products are manufactured. A product which is certified and *also* manufactured to UL specification becomes "listed" and may carry the UL mark. Astron power supplies are not so certified.

(see http://www.ul.com/ )

So, I guess the right answer was "sort of."
 
RE: Station Grounding  
by WB2WIK on August 18, 2004 Mail this to a friend!
Hate to nit-pick, but UL doesn't actually "certify" anything, at least not with regard to product safety (UL60950 etc). Since they are an NRTL that is also an FCC-approved EMC test lab, for electromagnetic compliance testing, they can "certify" stuff, for FCC; but that has nothing to do with product safety or using the UL logo.

They "recognize," or they "list." A component can be UL-R (recognized) without being listed, and thousands are. The UL-R process is mostly an investigation of materials used and their flammability ratings, calculation of creepage paths and so forth.

The listing process is more intensive and requires the Annual Service Agreement if it is to be continued for a period longer than one year. The Service Agreement is a chargeable plan, with associated cost per product, annually.

Many NRTLs can perform the same testing or investigation, and some do it far better; however, if you want to use the UL logo (which has some marketing advantage), you have to pay UL to do this, and for their Authorization to Apply UL Mark. That Authorization is mostly what manufacturers are paying for. Other NRTLs are equally licensed to do exactly the same work, both here in the U.S. and abroad, but UL is the "old man" of compliance agencies here and still has some power.

Personally, I use mostly NEMKO or TUV to do the same stuff, because they're friendlier.

WB2WIK/6
 
RE: Station Grounding  
by WB2WIK on August 18, 2004 Mail this to a friend!
AA4PB, I agree with you.

I've been up on Empire lots of times and there are hefty cables running down all four corners of the building (OUTSIDE) the building. I'd guess they're about #0000 gauge or so, and they're stranded copper. Under more modern thinking, they probably shouldn't be stranded, but what the heck, that's what was used and it's all still there after all these years.

But even large cables that are 1200 feet long have a pretty high reactance at lightning frequencies. Nothing up there is really "grounded" at all, at least not from an RF/lightning perspective. But I'm sure the "local ground" is a low-impedance common point for lots of stuff, even if it is all a quarter mile up in the air.

I have also witnessed the "let's tear out the lightning rods -- oops, no, let's put them back in!" phenomenon over the years. The current thinking is evidently to install "lightning rod" type systems that are taller than anything important, and nearby it. If you visit missile launch sites around the world, this is pretty evident: There are tall grounded towers, taller than the missiles or their silos, all around them, and I'm pretty sure that's for lightning protection, because they're not very visually attractive. Unless it's all "art deco."

I can't envision many amateurs having the budget or the wherewithall to do this, so we'll just keep doing whatever we do.

WB2WIK/6
 
RE: Station Grounding  
by AE6IP on August 18, 2004 Mail this to a friend!
http://www.wrh.noaa.gov/Flagstaff/science/lightnin.htm

is a good general description of how lightning is now thought to form and dissipate.

 
Station Grounding  
by K2YQ on August 18, 2004 Mail this to a friend!
Congratulations on a wonderful article and the stimulation of a great discussion thread.

My experience:
Just built an office/hamshack in my basement. Added three-wire electrical outlets. The third wire (ground) goes back to the electrical panel which is about 8 feet away from the outlet where my Yaesu FT-897's power supply is plugged in.

The ground wire continues from the panel directly through the top of the basement wall to a 8 foot copper ground rod.

I have also installed a ground bus using a copper pipe mounted on the wall near the outlet box. A separate copper wire attached to the ground circuit at the panel connects the copper pipe to the same copper rod which grounds the panel. The copper pipe is designed to function exactly as shown in the shack grounding recommendation from the ARRL handbook.

I use tinned copper grounding brad to connect the copper pipe/bus to the ground screw on the rig.

My experience is that with the copper bus attached to the rig there is a noticeable drop in noise compared to using the three prong plug alone.

What does this mean? The ground from the plug and the ground from the screw are both going to the exact same ground rod (which in itself is a controversial choice, but that's another discussion thread).

Could it indicate that the connection between the transceiver chassis and outlet ground is faulty?

Or does it mean that if a rig is powered by an AC/DC power supply the rig is floating ungrounded unless the ground screw is connected to a true ground?

Perhaps the comments of the original poster are applicable only in the case of equipment the has a direct chassis ground to an AC power source.

In other words do rigs with a built-in power supply have a better chassis grounds then rigs designed to be powered with an external AC to DC power supply?

 
Station Grounding  
by K4NHV on August 18, 2004 Mail this to a friend!
Nice article, Steve. Good topic for discussion.

I'm no expert on grounding, however I've shook hands with the lightning God more than once. Here's what I've done and it seems to be working:

1) I had the power company place a surge protector at my meter. It has it's own dedicated ground rod. It's supposed to keep surges from coming in from the power lines.

2) I have a dedicated outlet/breaker for my radio equipment running APC surge protection and battery backup (big momma with 4 backup batteries). Check this out. I'm using an Optima "Yellow Top" battery and a 10 amp charger instead of a power supply. The UPS will run the charger and the charger will charge the battery even if the power goes down. No 60 cycle hum either.

3) I use ICE lightning arrestors where the coax comes into the shack for both of my antennas. The arrestors have it's own dedicated ground rod. The arrestors also bleed off static in good weather giving me a "cleaner" receive. Any masts I have up are also grounded and I have a DC grounded antenna for VHF/UHF and a horizontal loop for HF. I use a coupler instead of a tuner on the loop.

4) I use the lug on the back of the xceiver and have a short piece of #8 solid core copper wire going to it's dedicated ground rod. I don't have any RFI problems, but I'm not sure if I can attribute this to that.

I haven't been unplugging anything. Next week, I'm moving back to my hometown in Nebraska and all of my antennas will be in the attic. Now, I'm more concerned about ice storms, hail and blizzards than lightning.

73,

Nick

 
Disconnecting in bad weather -- safe?  
by KC7YRN on August 18, 2004 Mail this to a friend!
If there's a thunderstorm a few minutes away, and you go outside and grab hold of coax connectors to move them to a grounding block, then aren't you at serious risk from fringe-area lihgtning bolts?
 
RE: Station Grounding  
by AL2I on August 18, 2004 Mail this to a friend!
After reading this thread and doing some additional web searching, I've decided to go the K4NHV way for my home QTH, and to completely isolate the equipment when it is not in use at my club QTH. Effectively using extreme versions of both competing visions as described and debated here, and as determined by the exigencies of my differing circumstances.

Thanks to all for a lively and illuminating discourse. I must now return to filling out my endless QSL cards. I am waaaay behind!

Whatever your own personal choice, when the lightning storms come, I hope you have plenty of cold beer on hand to enhance your viewing pleasure.

73,
Dave/al2i
 
Station Grounding  
by N0AH on August 18, 2004 Mail this to a friend!
Static is a good reason to ground your equipment. I've been bit standing next to verticals when the winds been blowing and having a static bleed off resistor going to ground cured this. I also was getting some RF burns on my arm when my amp was fired up and I was in TX until I grounded it. My 2 cents- Great write-up but I just don't think the author has had enough all around experience to know the benefits of grounding under some pretty typical operating situations.
 
RE: Station Grounding  
by WB2WIK on August 18, 2004 Mail this to a friend!
"Mmmmmmmmmmm....beeeeeeeer" - Bart Simpson

Regarding adding a chassis ground and seeing the noise level drop: I'd think this is actually a bad sign, and would want to investigate the noise source. Atmospheric static which is always there to some degree shouldn't decrease from the addition of a ground.

What *might* be happening is that you have a local noise source that is coming in via conduction, and you're routing it to earth by grounding your rig. I'd much rather find the source of the noise and kill it there, if at all possible. If it's really local (like a noise source from within your own home), your chances of finding it are probably close to 100%, with a bit of patience and some experimentation.

First thing I'd do, with a DC-powered rig (that is normally powered by an AC-to-DC power supply, outboard of the rig) is grab a 12V battery from somewhere and connect the rig to that, instead of the usual power supply. Then, I pull the MAIN breaker from the service panel and shut everything in the house off. Turn on the receiver and see if it's relatively noise-free; if so, turn the MAIN back on, and see if there's noise. If so, something in your home is causing it, and you can turn breakers on and off one by one to isolate the branch, and then, probably, the actual item generating the noise.

Even in a fairly large house with a panel full of breakers, all this takes only an hour or two, usually. I've done it an awful lot of times, at an awful lot of houses.

If you have the same noise using battery power and everything to your house "killed" as you do with everything in the house running, and your regular power supply, good chance you have something else in the neighborhood generating noise, and it may be beyond your control.

BTW, a lot of people cringe at the idea of dragging a 50-pound car battery into the shack for a test like this, but that's not necessary at all. Most of our modern solid-state transceivers will "receive" using only about an Ampere or so at 12V. You don't need to transmit for this test. An ordinary 12V lantern battery ($4.99 at Walmart) will power your rig for "receiving only" for quite a while and is a lot lighter than dragging around a car battery, and a lot more convenient than having to remove one from your car!

WB2WIK/6
 
RE: Station Grounding  
by WB2WIK on August 18, 2004 Mail this to a friend!
KC7YRN, why would you be disconnecting and reconnecting, or even touching, coax connectors at a grounding block at any time, let alone during a lightning storm? I don't get it. If you use a grounding block, that would be in line all the time, outside, and you'd never be messing with it.

N0AH, I have a great deal of experience in your situation and virtually every situation imaginable. A static bleed can be an RF choke, or even a resistor, as a real, low-inductance ground is never required for that. In most places, one doesn't even help, although evidently in some very dry places, one can help. But you don't need a ground rod, or any heavy wiring, for this.

Also, regarding RF burns with your amp on, and a ground solving that: This is *exactly* the kind of "band-aid" I was discussing, and so was Tom, W8JI. If grounding your station eliminates "RF burns," you've got a problem and grounding is like touching up the X-Ray because you can't afford the operation. RF voltage on equipment chassis is caused by many things, all of which indicate something wrong in the station: Either your feedline is conducting RF back into the station (which it shouldn't be); or your antenna is so close to your equipment that it's inducing current where it shouldn't be; or something. But in every single case, re-engineering the station is a better solution than grounding out the problem, if for no other reason than your station is guaranteed to work better once this problem's resolved.

Also, "grounding" a problem like this away can be a frequency-selective fix. A great ground that works at one frequency may be no ground at all at a different one.

WB2WIK/6
 
RE: Station Grounding  
by N7KKR on August 18, 2004 Mail this to a friend!
Great read Steve and good responses. A couple of points.

I believe one gent mentioned grounding was critical in hospitals. In years past there three criteria had to be met; 1) Resistance to ground had to be below a certain level, 2) The ground path had to be able to carry a certain amount of current, and 3) the various grounding points had to be "equipotential". This was originally designed for operating rooms that used ether and other flammable gasses as static control was crucial. Those were the days of conductive floors and the straps from the booties that went inside your sock. Later on, static and stray currents became an issue with equipment operations where there were good examples of sensors being easily disrupted.

Some of old grounding criteria isn't as valid today as manufacturers do pay more attention to making sure their equipment is RF and noise "low" as word gets out fairly quickly. Even rumors are jumped on fairly quick. Cell phones are required to be off not because of any single phone creating a problem but 30 of them within 50 feet being more the issue.

One thing that doesn't make sense is the "green button" labeling for outlets that supposedly meet a higher standard. Whether they do or not is frequently debated but noone disagrees that a splotch of green multiplies the price five fold.

Finally, "standards" are frequently set by industry groups. National Fire Protection Association (NFPA) is an example. As a former hospital engineer, I witnessed a couple of 13 year cycles where the "code" was changed to make the existing sprinkler heads noncompiant (I guess they were useless in the first place?) and hospitals had to replace them all otherwise they couldn't pass accreditation; a real big deal with insurance carriers and Medicare, etc.

Thanks to all for exercising my gray matter.... Warm regards.
 
Station Grounding  
by PHINEAS on August 18, 2004 Mail this to a friend!
Grounding really depends on your environment. Applications where you are sending low voltage DC power long distances with AC present. Grounding is essential!!!! Eddies , and common mode are common examples.

Saftey Grounds.

The whole idea behind this is to cause a safe path incase of a short. In AC systems in the US, you have a Ground conductor, a Grounded conductor, and a hot. The whole idea behind the safety ground is to back up the Nuetral(Grounded Conductor) in case fo a short circuit. is this absolutely necessary?...no Your equipment really does not care.

DC

Grounds are very important in DC. For the obvious reasons.


All depends on your application. I work around PWM Drives all day, and can tell you that a simple grounding problem can ruin your day. Daisy chaining your equipment is an ABSOLUTE NONO!!!!! If you are going to us a ground, always ground to a common point!!! If you ground things incorrectly, things will actually be worse.

I can talk all night about grounding, but I won't. I agree with Steve to a point, but just like I said, it all depends on the application.

Phineas
K0KMA

 
RE: Station Grounding  
by WB2WIK on August 18, 2004 Mail this to a friend!
I'm gratified this article has stimulated so much discussion. That's the whole point!

Thanks, guys. Keep it up if you like, but I'm happy already.

73 es DX (if you can find it!) I'm finding it right now, on 40 CW....

WB2WIK/6
 
RE: Station Grounding  
by N8MMZ on August 18, 2004 Mail this to a friend!
N7KKR:

Wow! Equipotential grounding of the surgical field is still crucial in patient care areas because of the risk of causing ventricular fibrillation at low voltage low frequency exposure. Since you are potentially "cutting" the patient right there in a patient care area, the opened patient presents a great path for stray current flow that otherwise normal skin is resistant to. There are several other issues that are of concern in regard to that.

I was very surprised when my wife was quizzing me about those issues when she came home from doing her first surgery on an opened patient - it was fun to talk electricity with her!

A Pass/Seymour, Leviton, Hubbell hospital grade receptical is just that - hospital grade. A sampling of the production line has been collected - then devices with weights are plugged in to the receptacle to make sure that the blades will keep the device plugged in with all of the weight hanging off of it (i.e. a doctors' otoscope). The devices are also tested for heavier bladed plugs being yanked from them. All of this testing occurs ad naueseum and repeatedly. This ensures that you aren't getting a receptacle that is residential grade (not subjected to institutional plugging and unplugging) so that the docs won't run in to a bad outlet as often. I know from where you sat, you were replacing a lot of 'em, but it is because you remember the ones you replace - you forget about the ones you don't replace. They are 5x more, because if a patient dies on the table, and it is due to a receptacle failing, then the receptacle manuf. knows that they are one of the deep pockets that is going to get sued.

Yup - you had to replace a lot of sprinkler heads due to Central Sprinkler and others, but that was preventative medicine they wanted to get codified. Turns out that a lot of facilities weren't having inspections done properly - it may have been a back handed way to get the fire marshal off his duff and back in the annual firepump/sprinkler system inspection business. So many building canges are allowed if you have a sprinkler system (i.e not as many fire dcoors, smoke dampers, sometimes no fire alarm system, etc...) that they want to make sure a sprinkler system isn't a single point of failure for life safety. Sure, sometimes things may slip into the code for manufacturer wellfare, but the biggies (like exclusion of models, or things that would require massive compliace) are guarded pretty well by the representation of NFPA. In other words, show me another code that's better.

As far as grounding and bonding of transmitters, I think a lot of that has been clairified in a later edition of the NFPA 70, but in my 1999 version, there are certainly some issues under articles 800, 810 that suggest requirements - but it could be open for interpretation. I would encourage the author to read NEC Article 810-78 and work back from there - I'm going to keep my opinion to myself other than to say when in doubt, ground it out (except make sure that the neutral and ground are ONLY bonded at your service entrance panel and not downstream panels in a 120/240-3wire system - and make sure that your grounding system complies with Article 250).

73's N8MMZ
Jonathan Morris, Man of Leisure and Gentleman Farmer.
Electrical Engineer, Retired
Grad Student, Retired
 
RE: Station Grounding  
by KE4PJW on August 18, 2004 Mail this to a friend!
>>>Commercial BC stations, at least for FM and TV, can have pretty poor grounds because they're located up very high above ground. For example, most NYC FM-TV stations are on the 82nd floor or above in the Empire State Building (espcially now since WTC no longer exists -- but when WTC was active, the transmitters were higher than that). This is almost a thousand feet above earth. Grounded? Hmph. <<<

It's my understanding that you want to tie all of those stations' grounding terminals into the grounding system of the building. Be it a system that was installed to act as such, or into the steel that is used the in framing on the building.

When a lightning strike occurs and **induces** a voltage into the the electrical system of the building, antenna system and the building itself, everything rises and falls at exactly the same rate so that you don't get potential differences between those three systems.

[Please note I am not addressing direct strikes, because only God can help you then ;) ]

I don't do this stuff for a living and my best source for this information has been Polyphaser's website, so I could be misinformed.
 
RE: Station Grounding  
by AE6IP on August 19, 2004 Mail this to a friend!
The Empire State Building is, rather, a good example of grounding and lightning protection. The ESB carries a lightning rod as its highest points, and has an extensive, well designed grounding system -- especially for all of those broadcast antenna; which are all below the level of the lightning rod.

The ESB's official web site estimates that the building receives an average of 100 lightning strikes each year. That's the equivalent of 1 each three days.

 
Station Grounding  
by KC0NYK on August 19, 2004 Mail this to a friend!
Here are a couple of reasons for station grounding:
1. It is MANDATED by the National Electrical Code
2. It is a SAFETY ISSUE
3. If you do have a fire and you have no or improper grounding, your Homeowner's Insurance will probably not pay off.
4. Electrical burns are extremely painful if you do not manage to die.

Enuff said.
 
Station Grounding  
by K4GLM on August 19, 2004 Mail this to a friend!
Nice article, Steve
And a good thread!
I ground; many rods tied together. I live in Florida, and have lost a lot of stuff to induced lightning over the years. The "circle" of ground rods around every building has helped for me.
I grounded everything in my station with flat braided jumpers. I did it to keep the 15 meter signal out of my kid's computer speakers, and keep my computer from rebooting itself on QRO! It worked, and is a plus for safety if the third prong doesn't work.
A cute story from field day: Three hams around a table and my FT-101ZD (Tube finals). Jerry is logging on paper, a spiral notebook. The Radio does not have a ground (hard to route it into the trailer...). The spiral wire gets hot enough to burn and brand his knuckles! Ouch! Again!
Those metal boxes work better at sheilding if the induced voltage can be held down. The antennas were matched precisely, as were the feed lines. The spiral wire was near the RF cage.
While I don't fault your arguments, I think I reap another advantage from grounding. My biggest problem is often noise, static crashes. I have a 60 foot vertical with a big ground system,(and a large bleeder resistor to ground) and it is very quiet on receive. I have a multiband vertical with elevated radials, and it is terribly noisy. This was unexpected, and I believe the grounding is what helped.
All the Best
Shannon Boal K4GLM
 
RE: Station Grounding  
by W8JI on August 19, 2004 Mail this to a friend!
If grounding your station reduces noise, prevents or eliminates RFI, or stops RF burns, you have an antenna system or equipment design problem. Something is abnormal, something is wrong.

You may have no choice but to live with that problem, but it CLEARLY indicates you have a problem someplace.

There is absolutely no reason to have a ground for RF purposes if the station is well-engineered, but sometimes we live with what we can do.

Safety is another issue entirely. All of the equipment should have a common ground and that common ground should connected to the electrical safety ground. Any feedline entering the house should be grounded to the utility ground OUTSIDE the house with a low impedance high-current connection.

I know many people won't do that and find a million excuses why they don't need to, but that's what we should do if we want to be reasonably safe.

SWR being low or high has NOTHING to do with needing a balun, or having RF on cable shields. I don't know why that rumor keeps being brought up like it is a fact.

If you have RF on equipment chassis or cables, you have a problem other than just what SWR might be.

73 Tom
 
RE: Station Grounding  
by WB2WIK on August 19, 2004 Mail this to a friend!
KC0NYK, can you cite the section of NEC that mandates consumer electronic equipment (or ham radio equipment) chassis grounding?

I'd sure love to see that.

WB2WIK/6
 
RE: Station Grounding  
by KA4KOE on August 19, 2004 Mail this to a friend!
You need to reference Article 810.51 of the current NFPA 70, which states in part...

"810.58 Grounding Conductors — Amateur Transmitting and Receiving Stations.

Grounding conductors shall comply with 810.58(A) through (C).

(A) Other Sections. All grounding conductors for amateur transmitting and receiving stations shall comply with 810.21(A) through (J).

(B) Size of Protective Grounding Conductor. The protective grounding conductor for transmitting stations shall be as large as the lead-in but not smaller than 10 AWG copper, bronze, or copper-clad steel.

(C) Size of Operating Grounding Conductor. The operating grounding conductor for transmitting stations shall not be less than 14 AWG copper or its equivalent."

and Article 810.15, which states

"810.15 Grounding.

"Masts and metal structures supporting antennas shall be grounded in accordance with 810.21."

finally, 810.21, which states

"810.21 Grounding Conductors — Receiving Stations.

Grounding conductors shall comply with 810.21(A) through (J).

(A) Material. The grounding conductor shall be of copper, aluminum, copper-clad steel, bronze, or similar corrosion-resistant material. Aluminum or copper-clad aluminum grounding conductors shall not be used where in direct contact with masonry or the earth or where subject to corrosive conditions. Where used outside, aluminum or copper-clad aluminum shall not be installed within 450 mm (18 in.) of the earth.

(B) Insulation. Insulation on grounding conductors shall not be required.

(C) Supports. The grounding conductors shall be securely fastened in place and shall be permitted to be directly attached to the surface wired over without the use of insulating supports.

Exception: Where proper support cannot be provided, the size of the grounding conductors shall be increased proportionately.

(D) Mechanical Protection. The grounding conductor shall be protected where exposed to physical damage, or the size of the grounding conductors shall be increased proportionately to compensate for the lack of protection. Where the grounding conductor is run in a metal raceway, both ends of the raceway shall be bonded to the grounding conductor or to the same terminal or electrode to which the grounding conductor is connected.

(E) Run in Straight Line. The grounding conductor for an antenna mast or antenna discharge unit shall be run in as straight a line as practicable from the mast or discharge unit to the grounding electrode.

(F) Electrode. The grounding conductor shall be connected as follows:

(1) To the nearest accessible location on the following:

a. The building or structure grounding electrode system as covered in 250.50

b. The grounded interior metal water piping systems, within 1.52 m (5 ft) from its point of entrance to the building, as covered in 250.52

c. The power service accessible means external to the building, as covered in 250.94

d. The metallic power service raceway

e. The service equipment enclosure, or

f. The grounding electrode conductor or the grounding electrode conductor metal enclosures; or

(2) If the building or structure served has no grounding means, as described in 810.21(F)(1), to any one of the individual electrodes described in 250.52; or

(3) If the building or structure served has no grounding means, as described in 810.21(F)(1) or (F)(2), to an effectively grounded metal structure or to any of the individual electrodes described in 250.52.

(G) Inside or Outside Building. The grounding conductor shall be permitted to be run either inside or outside the building.

(H) Size. The grounding conductor shall not be smaller than 10 AWG copper, 8 AWG aluminum, or 17 AWG copper-clad steel or bronze.

(I) Common Ground. A single grounding conductor shall be permitted for both protective and operating purposes.

(J) Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the radio and television equipment grounding electrode and the power grounding electrode system at the building or structure served where separate electrodes are used."

Thats says it all. Also reference the National Electrical Safety Code, and applicable portions of the Universal Building Code, 2000 Edition.

Philip Neidlinger, PE



 
RE: Station Grounding  
by K5UJ on August 19, 2004 Mail this to a friend!
Re grounding vis a vis lightning protection, a year or two ago QST ran a multipart series by one of the polyphaser (or is it polyphasor?) guys and (absurdly reductionist summary follows) one of the conclusions seemed to be that if you are going to do grounding etc. for lightning protection you have to pretty much do the whole megillah (perimeter ground, single point entrance for everything via grounded bulkhead, and so on) as found in a commercial installation in order to get any benefit. Doing the job halfway might invite more damage than what you would experience if you simply moved all feedlines away from your shack building, and completely disconnected everything inside from any wiring. Since ham stations are usually in people's houses, and aren't usually intended to be in operation 24 hrs/day the latter method probably works better for a lot of hams. I have a hunch that when a ham says he grounded everything and lost a lot of gear following a strike, he probably didn't really go all out and dot every i and cross every t in the grounding scheme. This isn't a criticism -- following all of the professional guidance is both costly and a lot of hard work (can you say Cadwelding and Ditch Witches?). For most of us we're probably better off pulling our feedlines away from our houses when we're QRT and unplugging everything inside.

Memo to the SWR Know-It-Alls: When you smugly preach to the rest of us such trite sayings as: "No dx station ever told me I was uncopyable because of my high swr" you are implying a correct message but you are either deliberately or ignorantly only telling half the story. The other half, which is why some of us DO try to achieve reasonable loads for our transmitters to work into is that modern gear and materials (coax) simply work better, especially at QRO with a nice pure resistance 50 ohm load. Tank circuits are happier, as are feedline dielectrics. Try telling some C.E. at a broadcast station that he can run his dx50 into a 3:1 swr and see what he says. (Yes I know the dx50 will shutdown but that's not the point.)

73
 
RE: Station Grounding  
by WB2WIK on August 19, 2004 Mail this to a friend!
Philip, I'm well aware of NFPA 70 and their guidelines.

Those are not harmonized codes, nor are they enforceable. If you disagree, please cite legislation harmonizing them, because I sure can't find any.

WB2WIK/6

 
Station Grounding  
by KA4KOE on August 19, 2004 Mail this to a friend!
Hey, the guy wanted to see the applicable codes on amateur grounding in NFPA 70, so I cut and pasted it for him.

Harmonizing? New term. It all depends on what the local Authority Having Jurisdiction observes in your city/county/state. Calling your local inspections department will clear that one up. Local code officials, at least in this neck of the woods, are notorious for creative interpretations of the various codes. I've had more than one run in with a local fire marshal, and one time had to get an elected official to intervene in order to get a ruling on an incorrect, in my opinion, interpretation, from state level folks.

It should be mentioned that all the codes published by NFPA are "minimum" standards for life and property protection.

The reader is encouraged to research further.
 
Code enforcement  
by KA4KOE on August 19, 2004 Mail this to a friend!
One more thing I forgot. If you have to get a building permit for new construction or renovations, or a certificate of occupancy from a code official, they are enforceable, if the inspector is worth his salt. Of course, this still depends on the local inspectors.

Amateur stations, however, not being part of commercial structures built for businesses or with tax money, or where the general public has access, usually will "fall below the radar".

It always pays to follow good installation practices for any installation, which goes without saying.
 
RE: Station Grounding  
by WB2WIK on August 19, 2004 Mail this to a friend!
Philip, "harmonizing" is the legal term for codifying proposed standards. NFPA has proposed standards, and so do lots of independent agencies, which is what they are. They're not a government entity and have no power to codify or enforce anything.

Once codes are harmonized, they become law.

Nothing in NFPA 70 is law, here (in Los Angeles).

It would be difficult to enforce (say in a court of law) selectively enforced code. An example would be that by most standards and definitions, amateur radio equipment, whether it "transmits" or not, is "consumer electronic apparatus." Consumer electronic apparatus has no standards with regard to fire preventive safety by design or deployment, other than common sense. (Remember, UL60950, etc have nothing to do with law and compliance is totally voluntary.)

Also, "amateur radio equipment" that really does transmit includes battery-powered handheld equipment which cannot possibly be held to the same standard as, say, kilowatt amplifiers containing 4000V power supplies. Should the code imply that anyone using a hand-held transceiver drag a ground wire along behing them?

Should low voltage DC powered equipment, even for home stations, be held to the same standard as AC mains powered equipment? How about equipment connected only to internal antennas?

The variables are why most of this stuff is not codified, let alone harmonized.

WB2WIK/6

 
Harmonizing  
by KA4KOE on August 19, 2004 Mail this to a friend!
Agreed.

You've probably noticed that the NFPA 70 text I cut and pasted says NOTHING about grounding your RADIO, just your antennas and structure.

I hope you did not take my first posting as implying you were unfamiliar with the NEC, but I put it up mainly for the benefit of those who hadn't read it or were totally unfamiliar with it.

It seems like things in California are quite different and lots stricter than in the south, and I am not surprised. I hear NYC is probably the worst in terms of codes, unions, etc., and enforcement.

What people DO get absolutely stark raving crazing about is the Americans With Disabilities Act. Leave out something in a design that inconveniences someone and you're likely to get sued.

Good article Steve. Now go post something on DED14.

PHILIP
 
RE: Station Grounding  
by AA4PB on August 19, 2004 Mail this to a friend!
For most of us we're probably better off pulling our feedlines away from our houses when we're QRT and unplugging everything inside.
-----------------------------------------------
My question is: how many people actually do that faithfully? I'll bet not many - unless they seldom get on the air.
 
RE: Station Grounding  
by WB2WIK on August 19, 2004 Mail this to a friend!
Agreed, very few actually pull everything and toss it out the window when they're not on the air.

Even those that try could forget something, like disconnecting gear from the AC mains and telephone lines.

Most of us all operate a bit under the assumption that our luck will hold, when it comes to lightning.

I'm real familiar with NEC, although I don't necessarily catch every revision and update; but I try to keep on top of those sections that affect us. It's evolved, like most code, by an accumulation of intelligence based on experience and common sense.

But it's impossible to prevent accidents altogether. One of the earliest YL hams, in the 1920s-30s, was the grandmother of a lady I know in Pasadena, CA, who is also N6NB's ladyfriend (that's how I know her). She was married to a ham, and used his plate-modulated AM transmitter on the air.

Back in those days, it was common to manually short out the modulation transformer secondary to work CW, and then remove the short to work phone. It was necessary to turn the high voltage "off" and wait for it to bleed down before reaching inside the guts of the transmitter to make this change.

Ooops. She died at a fairly early age, forgetting to do just that. Probably one of the very first SK YLs to be "killed in action," operating her rig.

Stuff like this can still happen today. Be careful!

WB2WIK/6
 
RE: Station Grounding  
by W6TH on August 19, 2004 Mail this to a friend!


The word is ROULETTE When you gamble with Electrons and such.

Reading of and about Electrons, I believe they have a mind of their own.

Grounds or no grounds have been hit quite often and is like a earthquake, never know when it will hit. However my animals know as they go sort of strange.

My lightning hits were about 40 miles away from the storm on a bright dry sunny day. Beating around a 150 foot radius and yet not striking my tower is amazing as it is not grounded in any way or fashion.

Steve, all kidding aside, great article and sure enjoyed reading all posted, even though it does drift to whereas that little terminal was very little noticed.

Write some more on any subject and I am positive you will have many readers and those with entirely different stories. Make ham radio come alive.

.: 73, W6TH
 
RE: Station Grounding  
by WA1RNE on August 19, 2004 Mail this to a friend!

Looks like everyone is all grounded out....
 
RE: Station Grounding  
by RAZOR_87FIS on August 19, 2004 Mail this to a friend!
Some interesting electricity can be found here:

http://205.243.100.155/frames/longarc.htm

Wonderful reading.
 
RE: Station Grounding  
by AL2I on August 20, 2004 Mail this to a friend!
Please read no further if you sicken easily!

Well, this thread certainly ground to complete drainage. There were a few electrifying comments, and the currents of thought were often at opposing polarities, but everyone was able to discharge the full potential of their wisdom without too much resistance, and the high tension we have experienced in parallel threads were not induced into this series of comments. Truly, the capacity for hams to spark the intellect of other hams with inductive logic is Watt brings the unimpeded power to our hobby.
 
Station Grounding and Astron  
by N1KHB on August 20, 2004 Mail this to a friend!
My experience and theory of grounding both in the ham world and in my almost 40 years of work in electronics generally follow the author's.
I would add however, that I have more than one case where adding an earth ground actually made things worse. You'd be surprised how many times a ham asked me about this problem or that and where appropriate, I suggested ungrounding and then get a report that the problem was either solved or at least improved. Additionally, it gives operators something to think about when I remind them that they are ungrounded everytime they operate portable or mobile. They think for a few seconds and say "oh yes, that's right".
One last point, and I hope all readers have read down this far - PAY ATTENTION WHEN USING AN ASTRON POWER SUPPLY! Astrons are nice supplies. I'm not knocking them. We even use them at Yale U. where I work. All Astrons that I've used (and possibly others) come from the factory with the minus (-) output side internally linked to earth. Most hams don't know this fact and no mention is made by Astron. At the very least, be aware of this connection and the possible RF benefit as well as consequence. I recommend unlinking this connection. You can always reconnect it externally later if desired. Like a station ground, it may help, but it may also hinder.

SSB skeds always invited.

73,
Joe N1KHB
 
RE: Station Grounding  
by N8MMZ on August 20, 2004 Mail this to a friend!
AL2I:

Your comments are rather shocking.
 
RE: Station Grounding  
by N8MMZ on August 20, 2004 Mail this to a friend!
WB2WIK:

The following is an excerpt from the city of Los Angeles code website (where you can buy their code):

"Electrical Code -- Published by National Fire Protection Association (NFPA)
Based on 2001 California Electrical Code (Based on 1999 National Electrical Code) with L. A. City Amendments. See below for purchase information."

Hmmmmm........ Like most municipalities, the codes have some specific requirements (prob. some seismological requirements in addition to permits, etc...), but are based on the NEC. There is no other U.S. org. that puts out an Electrical Code - unlike all of the umpteen mechanical and plumbing codes out there.

Reference the 1999 NEC Art 810-71 for compliance requirements of Amateur Transmitters. I will let you look it up yourself - the NEC may be enlightening reading for you.

Yes - many state laws require enforcement of building codes - failure to comply is cause for revoking the rights to occupy a structure - or if your building were to burn down could be cause for your insurer to deny coverage.

Cheers' - N8MMZ
 
RE: Station Grounding  
by N8MMZ on August 20, 2004 Mail this to a friend!
WB2WIK:

"Should low voltage DC powered equipment, even for home stations, be held to the same standard as AC mains powered equipment? "

Read up on power limited circuits, low voltage circuits, and separately derived voltage requirements. You really should become familiar with the latest edition of the code - a lot has changed since it went to an 8 1/2" x 11" format.

73s de N8MMZ
 
RE: Station Grounding  
by N8MMZ on August 20, 2004 Mail this to a friend!
WB2WIK:

Refer to 1999 NEC Article 90-2 for the scope of the NEC. You will see that it does not apply to hand held radios.

Refer to Article 90-4 for statutory enforcement requirements.

A thoughtful reading of Art. 90-1(c) "This Code is not intended as a design specification nor an instruction manual for untrained persons." will lead one to the notion that the writers of the code are assuming that amateurs, by examination, have demonstrated a certain level of training or knowledge that will allow them (amateurs) to understand applicable portions of the code: Art. 810 Part C, being that portion.

73s de N8MMZ
 
RE: Station Grounding  
by AA4PB on August 20, 2004 Mail this to a friend!
I would add however, that I have more than one case where adding an earth ground actually made things worse
----------------------------------------------
I have never seen a case where a properly installed single point ground made anything worse. Simply adding a ground without any consideration for single point techniques may indeed cause ground loops or other problems. That does not mean however that one should avoid using grounds - it means that you should use proper grounding techniques.

 
RE: Station Grounding  
by WB2WIK on August 20, 2004 Mail this to a friend!
I think the "adding a ground made things worse" comment pertained to RFI, and a questionable RF ground. And if so, I completely understand how this could be possible.

Single point grounding is surely a good goal, and prescribed by code, but isn't economically or practically feasible in many cases. If I add a #12 wire, 100 feet long, from my station to my service panel and its ground, and also use #12 wires, 100' long each, to connect that same point to my telephone, cable TV, satellite dish and other lines, so they're all connected to the same point although spread out over hundreds of linear feet, is this a single point ground?

For a 60 Hz signal, perhaps. For a higher frequency signal, probably not. For lightning energy, which emulates RF in many ways, also probably not. Even if it were, the conductor wouldn't be adequate.

To rearrange the home wiring, and the station, to serve a useful purpose of single point grounding, can be a costly, intrusive exercise. Those in high lightning risk areas should investigate what can be done to protect themselves.

But this article wasn't about any of that.

The intention here was to provide a counterpoint to the long-touted proclamation, "Don't even bother going on the air until you have a good ground installed!" which evidently has been scaring people *off* the air for many years. We can see that by the number of questions posted here and lots of places in this vein.

"I'm on the second floor, and really can't run any sort of decent ground. I guess I shouldn't transmit until I can move, huh?" questions abound. It's ridiculous.

The reply comments here and received off-site via personal e-mail is about five-to-one in favor of "I'm not using any sort of ground, and never have, and I've been on the air for years with no problems." Many of those replies are from engineers who happen to be hams.

Possibly that's similar to, "I never wear seatbelts, never have, and I'm still alive and drive every day." But I think not.

WB2WIK/6

 
Lightning and RF  
by KA4KOE on August 20, 2004 Mail this to a friend!
Yes. Not only does lightning emulate RF but radiates copious amounts, as we 160m fans grudgingly acknowledge!!!!!

This is an efficient mechanism on why lightning kills electronics without direct strikes, ie induced voltage in the wires via EMP.
 
RE: Lightning and RF  
by WB2WIK on August 20, 2004 Mail this to a friend!
I was going for electromagnetic pulse training for a long time before I found out I spelled the course wrong, and it should have been, "EMT."

Darn, what a waste of time!

 
RE: Lightning and RF  
by W6TH on August 20, 2004 Mail this to a friend!


Improper grounding can create a lethal hazard. Even if you advert danger, ground loops are the most common cause of AC line frequency hum in sound systems. So it pays to learn about grounding, and use what you learn.

With grounds the most common experience is "the more the merrier". As you add more, however, you usually reach a diminishing returns (no pun intended) situation where there is no *observable* improvement: that's usually a good place to stop. There are also exceptional circumstances where grounding increases noise problems, but these, in my experience, are much rarer than the pundits who preach against "ground loops" seem to think. Even a semi-quantitative theoretical treatment of grounding in oversimplified situations requires heavy math at RF. Experimentation is thus required even if one has done elaborate calculations. It's often easier to use the theory as a guide to what to try, and then experiment.

.:No ending to grounds, more comments?
 
Station Grounding  
by HAMDUDE on August 20, 2004 Mail this to a friend!
I had no idea Katz could be so smart and yet so stupid at the same time. Anyone who advocates no ground thats a so called ham for 39 years must be senile. This article is the biggest pile of rubbish I ever read. The author is a self proclaimed know it all who obviously doesnt know his a$$ from a hole in the ground typing up garbage like this.
 
Barbarians  
by KA4KOE on August 20, 2004 Mail this to a friend!
Reminds me of the sacking of Rome...destroy that which you are incapable of understanding.
 
Station Grounding  
by K4NHV on August 20, 2004 Mail this to a friend!
OK, I've heard some good comments. But now, it looks like everything is going downhill. Thanks to all for their constructive thoughts. I've definitely learned some good things here . . .

73,

Nick
 
RE: Station Grounding  
by AE6IP on August 20, 2004 Mail this to a friend!
Despite the way it's taught in History of Western Civilization classes, Rome wasn't sacked by those who couldn't understand it. It was sacked by those who didn't believe in it.

 
RE: Station Grounding  
by W6TH on August 21, 2004 Mail this to a friend!


Friends Romans And Country Men, lend me your ears:


Will America survive with no ground?

To be or not to be that, is the question.

.:
 
RE: Station Grounding  
by KA4KOE on August 21, 2004 Mail this to a friend!
"Despite the way it's taught in History of Western Civilization classes, Rome wasn't sacked by those who couldn't understand it. It was sacked by those who didn't believe in it."

Here we go again....missed the point entirely and focusing only on minutae.

Marty, you need a beer. Join the already growing throng and have a good lager here in Savannah on River Street.


 
RE: Station Grounding  
by K1OU on August 21, 2004 Mail this to a friend!
Anybody smell anything around here? Perhaps the smell of a horse beaten to death?
 
OU is green  
by KA4KOE on August 21, 2004 Mail this to a friend!
Jerry

You look kinda green around the gills in your photo. You need a beer too!

P
 
RE: OU is green  
by K1OU on August 21, 2004 Mail this to a friend!
No, Philip....too many beers. And after too many beers, I've been know to break out in handcuffs.
 
Station Grounding  
by KN4LF on August 21, 2004 Mail this to a friend!
Steve great article. It's rare to see a technical subject accurately presented in any amateur radio forum nowadays.

I live in west central Florida the lightning capital of the U.S. with 120 thunderstorm days per year, so have extensive antenna grounding for lightning strikes. No matter the time of the year when I'm not operating my rigs and linears are unhooked from the power mains, antennas and station grounding bus. But even that's not totally foolproof, as I have seen lightning damage electronic devices totally unhooked from everything. The culprit being an EMP much like emitted from a nuclear weapon explosion.

My station is set up so that all incoming cables are unhookable at the window entrance and directly grounded outside. I also have the station, power mains, cable TV/Internet and telephone grounds all tied together with #2 solid copper wire, to try and keep everything at the same potential. Each of my antennas are groundable to four ten foot long one inch outer diameter copper water pipes spaced twenty feet apart. The grounded wires are #2 solid copper wire. You don't want to use braided wire for grounding as lightning will fuse it open! This setup has taken it's share of lightning strikes safely to ground with no damage. But still I imagine that one day even this system will fail under a big enough lightning strike!!!

I do have a non daisy chained station grounding bus system, a habit from the boat anchor days and figure that it certainly can't hurt anything even now! I have had temporary compromise station/antenna setups in the past where the station grounding bus did assist in reduce RF in the shack. I also ran resonated 1/4 wave radials off of the tuner and that helped too.

BUT you and W8JI are correct in pointing out that a properly designed station does not need an RF ground. But I will aways feel more comfortable with a station DC ground setup.

73,
Thomas Giella, KN4LF
Plant City, FL, USA

 
RF Ground  
by W3DCG on August 22, 2004 Mail this to a friend!
OK, this continues to be entertaining and a learning experience for me!

I am confused about terminology, comments such as in mobile applications, there is no RF ground or something to that effect, I always considered the vehicle chassis and body to be the

"RF Ground."

1/4 wave veritical's- ground planes, I always thought of the ground plane radials, 1, 2, 3, or 4 of them, however many, as the "RF Ground."

Now I find out, I kept my station off the air when I recently moved, for weeks, putting off hanging wires in trees, until I could install, as suggested in some publications, including either the ARRL Handbook and/or ARRL Antenna Book, an "RF Ground." Even though at prior location, my "RF Ground," was so laughable, it did little if anything at all, yet I used it that way for 2 years!

But after moving, I went as close to the book as I could, installing my "RF Ground."
It consists of 1/2" tinned braid, about 2 feet in length, from my antenna tuner, to a copper pipe stub through the wall, to another 1' of tinned 1/2" braid, to a standard Electrical grade, 8' copper-clad steel rod, driven 6' down. Roughly, there is under 6' of length of conductors from tuner to "ground," which in this case, is actually, real earth ground. Next, as suggested for RF grounding, I made 2' lengths of wire, to 4' copper rods fashioned from copper plumbing pipe, and there are about 25 rods connected this way, stretched out driven into the ground. I have not yet connected this system to the power main entrance ground, as I have yet to discover it's location. Nor have I "encircled the house" with these 2 foot sections, nor do I plan to, and, I see no ground rod near the AC main service meter. So I thought, maybe that is normal for underground utilities? I do not know for sure.

As I often run unbalanced non resonant antennas (but now I'm hearing that resonance has nothing to do with RF feedback, but that confused me- so I went back to an article I reference often, concerning proper balun choice. There it does say, that for a conventional single wire Windom, some form of ground is important, but best kept outside, along with the 9:1 balun, and by all means the station should NOT be connected to that ground system. Makes sense, terminology clarification again indicated here, as in my mind, I'd consider that external ground system for the single wire fed Windom antenna to be "RF Ground."

I sometimes use what is called a Carolina Windom- in this case I consider my "RF Ground" to be inclusive of the tuner, which is "RF Grounded" as described earlier. Even the balanced fed G5RV is likely unbalanced because most of it is suspended over roof, some of it is not, and so environmentally induced current imbalance during transmit.

On 20m, either antenna, sometimes I notice RF induced irritation, meaning slightly buzzing more like white hiss, in my headphones, and computer speakers especially the sub-woofer, whenever power exceeds 80W, especially. Well I generally limit TX to 80W anyway, but do not tend to notice irritation at setting the power Full On, with the extra 20W, in my headphones, on SSB.

I was thinking about adding a 1/4 wave counterpoise section to my ground rod, accounting for the distance from the tuner to the rod, so that the added "counterpoise" would be 1/4 wave from the tuner to the end of the added counterpoise wire, merely laying it on the ground outside underneath all the ivy.
But now that this article has been written and author and most credible other contributors have spoken, it appears I need not waste my time with this, because likely such a move will not mitigate the problem. Apparently, current choke balun "line isolators" will fix, but the coutnterpoise will not.

Even though in practice, I have heard at least one or more stories, of this one simple procedure of adding 1/4 wave counterpoises at the tuner, having solved the problem, without having to buy chokes. Band Aid or not, if it fixed the problem, and fixing the problem the proper non band aid way does not do anything to increase signal strength, why would many hams bother doing it the other proper way, especially if they are already at their installational limitations? I'm interested in hearing the answer to this just in case fixing it properly does affect signal strength in a positive way, given the simple antenna's described.

Seems terminology clarification indicated here again,
as I always considered such use of 1/4 wave counterpoises at the tuner or very close to it, to be, "RF Ground."

Whatever the magnitude of my misunderstandings have been, and possibly still are, I think my set up is a very common set up, similar to a large number of stations. And so this is why I pursue more clarification, because invariably, it likely might help clear the fuzzy miscomprehensions in not only my mind, but others, as well.

Tnx for any embellishment, 73.




 
Station Grounding  
by AB5Q on August 22, 2004 Mail this to a friend!
Very interesting article however I would caution readers to carefully analyze the ramifications of having only a primary level of protection in a system.

A low impedance station ground is an inexpensive insurance policy. Its purpose is to provide the necessary back up just in case you underestimated something in your design. You are a much better engineer than I am if you can design a reliable and safe system without providing back ups. In this scenario, I consider the primary systems as the electrical safety ground in the power feed to the shack, the lightning arrestor on the lead-in entering the building and the antenna ground. If any of these primary systems should fail, you could lack adequate protection from an unexpected and catastrophic event. The station ground provides an adequate backup for at least two of the three primary system failures.

Is a low impedance station ground necessary? By all means yes, it’s the same as asking if seat belts are necessary in a car. Following your logic, the answer would no because it doesn't affect the operation of the vehicle. However, if you should have a catastrophic event such as a head on collision, you’ll be glad you had them on. Bottom line, a low impedance station ground is a good engineering practice and is recommended by most if not all modern amateur radio equipment suppliers.

The SWR subject seems to deviate from the subject at hand, but I think that I follow the analogy. One theory why SWR meters were not popular in the 60’s is that mainstream technology (vacuum tubes) did not require the device. During the 1960’s, efficient, high power transistors where probably nonexistent, not economically feasible, or not ready for integration into amateur radio. As the technology progressed, the shortcomings of solid state technology were understood and necessary engineering controls put into place. One of those shortcomings was the affect of impedance mismatch on transistor reliability. So, the need to maintain a SWR within specific limits became necessary. The SWR meter provides a simple means to determine that the necessary engineering controls are being followed and helps ensure reliable transmitter operation. As a result, SWR meters became more popular. Seems simple enough but maybe I’m missing something if you care to comment.

Regards,
John – AB5Q
 
RE: Station VSWR  
by W6TH on August 22, 2004 Mail this to a friend!


A suggestion for the VSWR, go to googles and look for this write up.

The Effects of VSWR on Transmitted Power

By James G. Lee, W6VAT

No matter how long you have been a ham, sooner of later you will be involved in at least one discussion of something called the Voltage Standing Wave Ratio, or VSWR, of an antenna system. There is a lot of good information available on VSWR as well as a lot misconceptions about what it is and what it signifies. Probably the most often misconception is that your VSWR should be as close to 1:1 as possible, otherwise " you won't get out very well." A 1:1 VSWR implies a perfect match between all elements of the antenna system. The only problem is that it is possible to have a low VSWR and still have some very serious things wrong with your antenna system. Other misconceptions such as a high VSWR causing television interference, or other unwanted problems are often heard and can cause unnecessary worry. The concept of VSWR is easy to grasp and its importance in an antenna system does not require an engineering degree to understand.
=====================================================
Now my voice of opinion:

There is much more following and he also goes into math which is extremely helpful above the basics.
I do not know him or such, but would be a good idea to find information as to VSWR. I enjoyed the reading and am sure you will get more benefit from his article than from many other sources.

W6TH

.:
 
Station Grounding  
by AB0N on August 23, 2004 Mail this to a friend!
Well said Steve. I do run a cold water pipe ground. Simply because it's available where my radio is. In the old days before SWR bridges were in vouge we mostly dealt with Tube based electronics. SWR was not as detrimental to the output devices as todays more fragile solid state devices. I like a good ground return on my tube stuff in the off chance a bypass cap should fail. I hate getting bitten by leaky caps discharging through the chasis through me to the cement floor. Ouch! I repaired an old Hallicrafters receiver, yes your basic 5 tube direct 120 VAC (No transformer) this one had one of the metal cabinents. Had enough voltage on the chasis to make you sing. I rebuilt the beast for dear old Dad. Anyway all new capacitors throughout and the problem was solved. I measured a very small leakage current of maybe 3 VAC. I think it depends on your situation. With a tuned antenna or suitable counterpoise it's probably unnecessary. With tube stuff, well maybe better safe than sorry. Your mileage will not doubt vary. I guess it's up to the individual to decide for themselves. Dave AB0N
 
Station Grounding  
by W2MB on August 23, 2004 Mail this to a friend!
Very well written article. The anecdote about the 7200V transmission line laying on the antenna caused serious credibility concerns though. I've seen 7200V transmission line instantaneously vaporize heavy steel cable and bake a roadway surface. I can't imagine 7200V transmission running above a residential dwelling.
 
Station Grounding  
by WA2JJH on August 23, 2004 Mail this to a friend!
Does anybody actually have a cold water pipe in their shack? Works great for XTAL radio's:)

The GND lug can be used for antitheft :)

I think hams would think they were cheated if their rig did not have a GND lug.

It is like cell phones. After much testing, it was found that a cell phone would work just as well with an internal antenna. However the consumer feels the need for an an antenna on thier hand held cell phones.

They would not buy s cell phone that did not hsve a pull out antenna.. The old cell phones needed an antenna. The LNA's and DBMs were not that good 10 years ago.

Try this on your modern cell phone. See if extending the antenna does anything. Even in fringe area's
 
Station Grounding  
by HF2PWA on August 23, 2004 Mail this to a friend!
THIS ENTIRE THREAD SMACKS OF ANTISEMITISM!
OH SORRY...WRONG THREAD!!!
 
RE: Station Grounding  
by WB2WIK on August 23, 2004 Mail this to a friend!
W2MB, the average residential dwelling served by overhead electric utility distribution indeed has 7200V running close by: That's the common and typical primary voltage to the pole pigs used to transform down to 240VCT for distribution to your home (if you have overhead utilities). 240V is not distributed pole-to-pole, hardly anywhere: The required current is too high, and thus the IR losses will be too high. The 7200V lines are obvious in that there are only two wires (no ground running along with them), and all their connections at support points and transformer taps are via long insulators.

In every neighborhood I've ever lived that had overhead electric power distribution, the 240V service drops from pole pigs to individual homes were the only place you'd ever see 240V wiring, at all. Everything else, and all pole-to-pole wiring, has been 7200V.

In my case, the 7200V distribution line (which is not considered "high tension" in the industry, at all -- it's considered residential distribution) ran on poles well behind the house, and pretty high above ground, with the telephone and CATV lines running separately, about 30 feet lower along the same poles. My tower was farther back in the yard than it should have been, and placed the element tips of my 20m beam almost directly under the lines. Who'd ever think a line would break and unluckily land across an antenna, without simply breaking the antenna (thin aluminum tubing, not much match for heavy gauge copper cable falling several feet)?

Well, now I not only know it can happen, but I also know this doesn't have to be instantly destructive.

Also, there is no way to calculate the short-circuit (or nearly so) current one of these lines can provide, because that depends on how far away it is from its source transformer, the gauge of the wire that carries it from that source to its destination, the condition of that line and its connections, and the existing loads already placed on that line. No one can calculate this, and there's no purpose in guessing. According to NJP&L, who owned the line that fell, it was a 40 year-old line and couldn't possibly provide more than 10A short-circuit current at the cul-de-sac end of the line where its only design load was one transformer having two residential drops that were designed to support 240V at 60A each.

It doesn't pay to make broad statements about these things, as I found out, myself.

WB2WIK/6
 
Station Grounding  
by KN4LF on August 23, 2004 Mail this to a friend!
P.S.

At one time I had a very large electrical half wave vertical tee antenna on 160 meters. I had a large wooden box at the base of the antenna which housed the parallel tuning network. On the box I posted a sign that said in large red letters, "DANGER 10,000 OHMS OF RESISTANCE". I got many comments about that sign and the public danger of that antenna, snicker snicker snicker!!!

73,
Thomas Giella, KN4LF
Plant City, FL, USA
http://www.kn4lf.com/kn4lf5.htm

Steve great article. It's rare to see a technical subject accurately presented in any amateur radio forum nowadays.

I live in west central Florida the lightning capital of the U.S. with 120 thunderstorm days per year, so have extensive antenna grounding for lightning strikes. No matter the time of the year when I'm not operating my rigs and linears are unhooked from the power mains, antennas and station grounding bus. But even that's not totally foolproof, as I have seen lightning damage electronic devices totally unhooked from everything. The culprit being an EMP much like emitted from a nuclear weapon explosion.

My station is set up so that all incoming cables are unhookable at the window entrance and directly grounded outside. I also have the station, power mains, cable TV/Internet and telephone grounds all tied together with #2 solid copper wire, to try and keep everything at the same potential. Each of my antennas are groundable to four ten foot long one inch outer diameter copper water pipes spaced twenty feet apart. The grounded wires are #2 solid copper wire. You don't want to use braided wire for grounding as lightning will fuse it open! This setup has taken it's share of lightning strikes safely to ground with no damage. But still I imagine that one day even this system will fail under a big enough lightning strike!!!

I do have a non daisy chained station grounding bus system, a habit from the boat anchor days and figure that it certainly can't hurt anything even now! I have had temporary compromise station/antenna setups in the past where the station grounding bus did assist in reduce RF in the shack. I also ran resonated 1/4 wave radials off of the tuner and that helped too.

BUT you and W8JI are correct in pointing out that a properly designed station does not need an RF ground. But I will aways feel more comfortable with a station DC ground setup.

73,
Thomas Giella, KN4LF
Plant City, FL, USA
 
RE: Station Grounding  
by KA4KOE on August 23, 2004 Mail this to a friend!
"Also, there is no way to calculate the short-circuit (or nearly so) current one of these lines can provide, because that depends on how far away it is from its source transformer, the gauge of the wire that carries it from that source to its destination, the condition of that line and its connections, and the existing loads already placed on that line. No one can calculate this, and there's no purpose in guessing."

Sure you can do this. You have to call the power company and ask what the fault current is at the transformer secondary windings, %Z, and KVA of the transformer in question. Then you have to do some plain ole EE calcs for short circuit current at your gear based on a bolted fault, which is worst case.
This will get you close enough to size your gear for the amperes interrupting current available at your gear. Residnetial stuff tends to be 10K amperes AIC at most. The small size of your service laterals (usually less than 2/0 AL) will tend to limit how much fault current will flow due to I squared R drop.

Of course, this is an estimate, but, in my opinion, will get you to within 10%, which is good enough to satisfy myself and the MAN.
 
RE: Station Grounding  
by WB2WIK on August 23, 2004 Mail this to a friend!
Philip, that's fine for calculating after the residential service transformer. But my discussion relates to primary service to that transformer.

The local power companies don't even have an accurate grasp on this data, or at least they surely didn't back when those lines were installed in the 1950s. The "max" fault current is a good one to know about, but there isn't any "min" that I know of.

Can you tell me, in your neighborhood, say at the primary of your nearest pole pig (or underground equivalent), what the short-circuit current is? This is the number at 7.2kV, probably, not at 240V. And if so, what is it?

73, Steve
WB2WIK/6
 
RE: Station Grounding  
by W8JJI on August 23, 2004 Mail this to a friend!
In my younger days I was grounded alot, and I never once got struck by lightning.
 
Station Grounding  
by OBSERVER on August 24, 2004 Mail this to a friend!
Steve (WB2WIK/6) stop while you are sort of, um, ahead?

What Philip indicated is very important information for those who design power distribution systems. When dealing with a 100MVA load the economics of not understanding a system’s ratings can be insurmountable. One miscalculated event and you are out millions of dollars worth of equipment and lost revenue with possible loss of human life. To say that the power company engineers do understand their system capabilities is a very bold statement. Philip is correct, this concept and accompanying calculations are quite basic and simple to understand.

Steve, what exactly is your occupation and level of education?
 
Station Grounding  
by K4NHV on August 24, 2004 Mail this to a friend!
Here's several articles on station grounding, equipment and technique. This is good stuff!

http://www.arraysolutions.com/Products/ice/10.html

73,

Nick
 
RE: Station Grounding  
by WB2WIK on August 24, 2004 Mail this to a friend!
OBSERVER, when you provide us with your callsign, or alternatively, contact information (like name, location, e-mail address), I think I'll be happy to provide you with any information I can.

In the meantime, anyone who does not plainly identify him or herself is a troll.

WB2WIK/6
 
Station Grounding  
by KE4ZHN on August 24, 2004 Mail this to a friend!
It appears this thread is beat into the "ground".
 
RE: Station Grounding  
by NC2W on August 24, 2004 Mail this to a friend!
I find it hard to believe that no one (anyone) at a given utility can produce the short circuit current for any given distribution system. Such calculations are required for sizing / specifing the construction and/or operation of the power system.

Sounds as if someone touched a nerve.

 
RE: Station Grounding  
by NC2W on August 24, 2004 Mail this to a friend!
To summarize my previous comment, I would agree with Philip, and the mysterious 'Observer'.

Eric
 
RE: Station Grounding  
by KA4KOE on August 24, 2004 Mail this to a friend!
Do I know the primary fault current at my pole pig? No, but I know who to call to obtain that information. It does help to have this information when doing your calculations, for the high side of the transformer.

However, for most routine small stuff, one assumes an "infinite bus" that can supply all the current the bolted fault can deliver. In practice, this magnitude will get you pretty close to what the actual value of fault current available is. The secondary fault current is limited by the pole pig's electrical characteristics.

Of course, at some point, the cutouts upstream will open at some value of current. The power company must know this value to size the cutout. Too small, and an entire neighboorhood is down due to a momentary surge. Too much, and things go boom.

Suffice it to say that the amount of current on the high voltage lines is enough to cremate you quite efficiently, but of course we all knew that to start with.

Anyway, not to detract from an excellent article, Steve. We all enjoy sane, adult, and occasionally humorous discourse. Please continue to write your good technical articles. I was particularly fond of the one describing power measurement in single sideband phone signals.

Cheers dude.

PHILIP
 
RE: Station Grounding  
by WB2WIK on August 24, 2004 Mail this to a friend!
I'm a dude?

Nah, you have to be dead for that status, e.g., DEDs.

If one is still kicking, is he an LED?

Seriously, I'd love to hear what reply you get when you call in requesting the short-circuit info. Here's the reply I just got, today, when I called in out of curiosity to LADWP (recollection of telecon, but pretty close):

"We don't provide that information unless requested in writing, and then we can only provide design data. Since the branch you're referencing is 45 years old and our records indicate only one maintenance in that period, the design data is probably inaccurate and would need to be verified. In all cases, the design data is optimum and the system degrades from that point forward. If you have a specific problem you feel needs attention, request service and the nature of your concern, and service will be provided in accordance with urgency."

And there ya go.

73!

Steve, WB2WIK/6




 
Low side calcs  
by KA4KOE on August 24, 2004 Mail this to a friend!
Here is a well known short-cut for low side fault current:

Get your transformer KVA rating and derive the maximum current at 240 volts, single phase (assuming its that, and not 208 volts, single phase, or some weird open delta arrangement)

( Transformer KVA / service voltage )/ %Z = Available fault current, assuming totally resistive load.

Example

50 KVA, 120/240 volts, single phase, three wire bank will have a maximum rated 100% demand current of 50/.24 = 208.3A

Assume 5 % Z, 208.3A / .05 = 4166.7 Amps fault available should you connect phase A to phase B to Neutral all at the same time, being suicidal of course, you with heavy crescent wrench in hand, rubber gloves, heavy suit, and face shield to guard you from the intense IR and UV flash of the arc.

Yep, its below 10K amperes.

Things get a little more complex for three phase systems, but the concept is the same.

Calcs do get very hairy when you have large motors turning into generators when the fault occurs. The wild thing is that the motors actually deliver current into the short until the rotors spin down after a few cycles.

Anyway, this is probably not germane to this discussion, but thought I'd pass it on anyway for those who may be interested.

P
 
RE: Low side calcs  
by KA4KOE on August 24, 2004 Mail this to a friend!
Being liable for any design errors, we must get things in writing!!!

Can't have it otherwise! Its like any other profession these days, gotta have liability insurance. Engineering insurance is not really all that bad compared to say, insurance for being a doctor of obstetrics.

The phrase they throw around is "reasonable standard of care". That way, when you're on the stand, you can say, "Yes your Honor, SEPCO told us in writing (holding up copy of affidavit) what we could expect from them in terms of fault current should the client's now departed husband complete a circuit from phases A to B accidentally."

ZZZZZZPPPPPPT, BANG!!!
 
RE: Station Grounding  
by KF6ARX on August 25, 2004 Mail this to a friend!
Well after nearly 40+ years repairing equipment, debuging, and designing Audio, RF, and in recent years computer gear, and responsible for doing RFI and emmisions testing, After years of studing the effects of proper grounding techniques on equipment design while doing RFI/Emissions testing for all of the various FCC,VDE,CE, etc.. I have to say that proper grounding is a GOOD thing. It reduces spurious noise, reduces unwanted emissions, and when done properly will reduce or even eliminate the damage from phone and power line lightning strikes.

On the subject of the UL cap.. The mis-conception that the .1uf cap in the UL approved equipment does not "ground" the rig is just that.. a mis-conception.. While it is not a DC ground, it is an AC ground.. and even in most cases that cap is in parallel with a hi meg-ohm (1-10M) resistor (or in many cases a special combinational unit with both parts in one package) in many installations to bleed off any differential charge that may develop across the cap. As to a "ground wire", in most cases that silly piece of 12GA to that rod 20 feet away is pretty useless as an RF ground due to the inductance in the wire which can actually develop a significant RF level across it and can give you some interesting effects along the way, and often not very nice. Skin effect comes into play big time at higher frequencies and power levels which has a direct effect on the type and number of ground point structures required. A 1" wide piece of copper tape is far more effective than a piece of 8GA wire at RF levels. Stringing chunks of 10GA between equipment to a rod or water pipe on the other side of the house is generally a bad thing to do. While it is all at DC ground it is NOT at AC ground!

Proper station grounding takes good understanding of the principles of how RF travels at different frequncies and effort to put into effect... effort that many are not willing to put forth or due to the "I never needed it before" mind set, feel that it buys them nothing. ARRL provided an EXCELLENT two part article back about two years ago in two issues of QST on proper station grounding.. I do not remember just exactly when but look for it. It is well worth reading.

-Rich
 
RE: Station Grounding  
by WB2WIK on August 25, 2004 Mail this to a friend!
Hi Philip,

If you contact your local utility service provider and request this, can you get the data and then verify:

"What is the ground fault current if one side of the 7200v line shorts directly to earth?"

Not line-to-line S/C current, but line to ground S/C current.

According to my local pros at Water & Power, it's not the same. The EIC last evening asked me to go outside and look up at the line I was referencing. "You see only two wires, don't you?" was the question. "Yes, I do." "Note there isn't a third wire. We only run two wires and they're both live, there isn't a neutral running with them."

I'd like to hear from you, if possible, regarding this and the question above.

Thanks!

Steve WB2WIK/6
 
RE: Station Grounding  
by K4JSR on August 25, 2004 Mail this to a friend!
Steve, you could have avoided all of this discussion
of grounding antennas, power lines, etc., if you had quoted The Amateur's Code, Article 5, "The Amateur is
balanced..."

This discussion is like the old electrician who only saw things in green and black. One day he passed away. His friends came by to pay their respects at
his wake. One was heard to comment, "Have you ever
seen his finger nails so clean?" The other replied,
"No, and don't he look neutral?" ;p

I will go away now, because as Cleopatra was overheard to say, "nobody likes a smart Asp!"
And since I am now retired, I am like the destitute
viper that could not afford a pit to hiss in.
That is why all of the PIT-THY comments!

73, Cal K4JSR
ZAP, Ga.
 
RE: Station Grounding  
by KA4KOE on August 25, 2004 Mail this to a friend!
"Hi Philip,

If you contact your local utility service provider and request this, can you get the data and then verify:

What is the ground fault current if one side of the 7200v line shorts directly to earth?"

I'll ask my buddy at SEPCO.

"Not line-to-line S/C current, but line to ground S/C current."

There is no neutral in OH distribution lines; just phase and phase. The neutral is generated on the transformer secondary (ie midpoint). Usually both phases shorted will produce the most fault, and we design for the worst case scenario. Again, I'll ask my buddy at SEPCO.

"According to my local pros at Water & Power, it's not the same. The EIC last evening asked me to go outside and look up at the line I was referencing. "You see only two wires, don't you?" was the question. "Yes, I do." "Note there isn't a third wire. We only run two wires and they're both live, there isn't a neutral running with them."

He's right. It isn't the same. Either way, you have either a line to ground fault or a line to line fault, you're still in for some fireworks. Again, neutral is generated on the pole pig secondary.

"I'd like to hear from you, if possible, regarding this and the question above."

I'll try and get you some answers as soon as I hear from my power company buddy. However, a minimum value does not concern us. Again, we must size our equipment to handle worst case situations, so a line to line bolted fault is what we usually concern ourselves with.

Regards

PHILIP

 
RE: Station Grounding  
by WB2WIK on August 25, 2004 Mail this to a friend!
Philip, I understand this, and you are educating me a bit on this subject. I'm not in the power generation/distribution industry, and never have been.

But my original story (scroll up about two miles) involved a line-to-ground fault. I never mentioned anything about line-to-line, but it seems all worst-case designs and calculations involve line-to-line (as probably they should).

Is it possible that since there is no 7200v "neutral" per se, the resistance in a line-to-ground fault could be so high as to create very little fault current, despite the bus being capable of dozens of megavolt-amperes?

Enquiring minds want to know....

Thanks for your help!

73

Steve WB2WIK/6
 
RE: Station Grounding  
by WB2WIK on August 25, 2004 Mail this to a friend!
If anyone still cares and is reading this stuff, here's something interesting that harkens back to the "original topic" here, which is station equipment grounding *not* for lightning protection. This is from an e-mail I received yesterday:

"Hi Steve!

"Just a quick note to tell you how much I enjoyed your grounding article. I get tangled up in this grounding situation with some of our customers that have some RFI. When I spend lots of time on the phone going through their station and recommend they dump ALL of the grounds, you can imagine what answer I get! God Bless you for having the fortitude to bring this touchy subject to light for so many.

"I have NEVER had a ground on any of my stations since 1956. My mentor and wonderful Elmer was the chief engineer at KMOX-CBS and how could this 15 year-old kid NOT do exactly as Larry advised? It was totally against all the books, advice, etc, but I followed it and later in my life, building the world's first 50KW sound reinforcement system for the Dead, I REALLY learned the trials and tribulations of ground loops! I have a chapter in my 1976 'Practical Guide for Concert Sound' text book with very clear drawings and explanations...oh my...more screaming...UNTIL they solved THEIR hum problems by removing a ground!"

(There's more to this, but it gets off topic about audio and rock & roll stuff.)

"Keep up the good work, Steve.

"Best regards,

"Bob Heil, K9EID
www.heilsound.com"

Anyway, there's a perspective from a long-time ham who's never grounded his station...just like I've never grounded mine!

73 all!

Steve, WB2WIK/6





 
Line to ground faults  
by KA4KOE on August 25, 2004 Mail this to a friend!
I think, if I remember from the last time I ran EDSA, a fault program the United States Navy endorses, that line to ground faults will be half of what line to line faults will be.

Makes sense, and no phasors to complicate things as one encounters in three phase systems.

I think you will find that your resistance to ground in your situation was significant, but more than the amount needed to melt your station cables or set them ablaze. A straight short would have tripped the primary protector quickly. Assuming an infinite bus (there's that term again) your current was probably something less than 200 amperes. From the NEC tables, a #3/0 THWN CU conductor is rated to carry this all day and not exceed 65 degrees C.

The really lucky thing for you was that you had some substantial resistance in your temporary connection to ground, but assuming RG-8 has the equivalent area in circular mils as #3/0 (I'm guessing here folks), 7200 volts to ground @ 200 amperes gives 32 ohms total R.

Anyway, I'll pass Mr. Faircloth's answer to you tomorrow when he calls me back at the orifice.

Feeee-leeeeep
 
RE: Line to ground faults  
by WB2WIK on August 25, 2004 Mail this to a friend!
"Line to ground faults will be half of what line to line faults are..."

Why would that be? I'm trying to think of some logical reason this makes any sense, at least in this particular application.

What does make sense is this:

7200v L-L, floating above ground as it should be.

Substation neutral grounded, or not, wouldn't matter much.

Substation 5 miles away, with the only common connection being "earth," which has varying and unknown impedance.

Now, let's define what a ground fault current ought to be:

I can't.

Can you?

I'll readily admit this is unfamiliar territory, and there may well be standards I've never heard of. But I'd like to know about them.

What are they?

I'll say one thing: I received a number of private e-mails (in addition to the one from Bob Heil, posted in part earlier) saying others have experienced residential primary power (c. 7200v or so) ground faults, and not one of them said anything about burning their houses down, or creating lightning bolts between dangling wire ends and earth.

Why is that?

Could it be this potential (pardon the pun) hazard just isn't? Or we're just lucky. I really don't know.

Let me know what you find out from the elder statesmen of the power grid, and I'll do a bit more research, also.

Interesting topic. Maybe not as exciting and sexy as DEDs, but it'll do for now.

Steve WB2WIK/6

 
RE: Line to ground faults  
by KA4KOE on August 25, 2004 Mail this to a friend!
OKAY, correct me. Is it 7200 L-L or 7200 L-G. Sounds like a 14.4 KV system if L-G; a common primary voltage.

P
 
RE: Line to ground faults  
by KA4KOE on August 25, 2004 Mail this to a friend!
The key is BOLTED fault, where a solid mechanical connection ensures that the shorting member won't be blown off.

What kinda faults did they experience?

I have heard of horror stories about persons getting hold of this stuff by grabbing live high tension wires, and the resultant closed casket funerals.
 
Station Grounding  
by OBSERVER on August 26, 2004 Mail this to a friend!
Man you are all over the place, I'm getting a headache.

There's a logical and simple explanation as to why the 7200V circuit breaker didn't trip when the line contacted the antenna. The rig wasn't grounded and the SWR meter wasn't installed. How am I doing Steve?

Observer the troll - spin doctor in training.
 
RE: Station Grounding  
by K4JSR on August 26, 2004 Mail this to a friend!
Getting back to station grounding, I do ground my
station. I do not ground it for RF or Lightning.
I do ground it, with a common bond to everything in
the set up because I have had the everliving purple
snot shocked out of me on a cold wintery windy day
because of static build up on my antenna system.
I don't like imitating Capt. Ahab taking on St. Elmo's
Fire. Elmo can just stay on Sesame Street!
You engineering geeks can argue all you want, but I
do know that giving static a place to go besides through me doesn't hurt a bit! I don't even worry about lightning hitting my antennas. That was only a
problem when I had a repeater on a mountain top.
As far as pole pigs go, if the pig can't be barbecued, it ain't no use to this troglodyte!
Besides, even the best installed power system gets blown to perdition when a class 4 or 5 hurricane blows into town! Power grids don't last, good barbecue do! (And good seafood eaten inland!) :-D
Furthermore, can't you two wait until 02 November to
poll pigs?

73, Cal K4JSR
Georgia's answer to common sense. (Poor Georgia!)
 
Engineering Geeks  
by KA4KOE on August 26, 2004 Mail this to a friend!
Hey Cal, don't irritate the geeks too much or they won't dream up any more battlecruiser rigs for ya' to spend your money on, vis a vis Yaesu FTDX-9000 or the ICOM IC-7800.

Or, they may sick their redheaded wives on you.

Feeeee-leeeeeeeeep
 
RE: Station Grounding  
by WB2WIK on August 26, 2004 Mail this to a friend!
Hi Philip,

The answer is: 7200v L-L

I'm trying to find out where the "G" would come from in an "L-G" situation, since the transmission lines carry no common along with them.

72 & I'll owe you one.

Steve WB2WIK/6
 
RE: Engineering Geeks  
by K4JSR on August 26, 2004 Mail this to a friend!
Irriitating engineer geeks is what we Technicians love
to do most! Besides the threat of Yaecomwood not making any new rigs just for me does not matter.
I cannot afford, nor would I buy, one of there multi-
Mega-Buck offerings. I will just stick to the mountains and go to the Ten Tec hamfest in September.
Those hillbilly injun ears *KNOW* how to build great radios!~
Now, back to you and WIK on polling pigs.
Oinkers away, my boyz! Just don't take any pigs in a poke!
Steve, just how do you get those pigs to respond to polls? I would think that the Pork Ranger would come
and make you stop!

73 and if this thread gets any longer you both could
stretch it between East Coast and West Coast, fasten it to some old tin cans and talk to each other direct!
See, folks! Technicians find practical solutions
while engineers just continue critical design reviews
until hell freezes over! (Technicians also know how to
troll engineers, also!)

Cal K4JSR CET (This has two meanings:
Certified Electronic Technician
Certified Engineer Terrorist
Certified Enigmatic Troglodyte
Uh, that's 3 meanings!...



 
RE: Engineering Geeks  
by K4JSR on August 26, 2004 Mail this to a friend!
Ah, my friend Philip. You said, "Or, they may sick their redheaded wives on you." [sic]

Well, gee, if I were sick I would want a nurse!
Sic her on me. We have a nice little airport here in Barrow County, where she could land. We would than
take her to Athens and feed her some of CW Williams fine seafood!

By the way, Steve and Philip, never lay siege to a
shorted pole pig. It may drop boiling transformer oil down onto you!

73 Cal K4JSR
Pork Chop, Ga.

Ps. Do hams from Massachsetts show their Boston Butts? (Feeble attempt at more ham humor)
(Some of us will just never LOIN!)

 
Point of it all...  
by WB2WIK on August 26, 2004 Mail this to a friend!
The purpose of this article was only to provide a counterpoint to the "must ground your equipment!" view seemingly held by many and literally keeping some off the air altogether in fear of having done something wrong.

The point's already been proven, based on tons of response.

We've migrated into discussions about electrical power grids and transmission, and this is another fascinating subject for me, but has nothing to do with the original article.

Many "experts" piped in with theories about how a severed 7200v residential transmission line, faulted to ground, would contain sufficient energy to blow to smithereens everything in its path, resulting in considerable destruction of hardware and possibly organisms. My counterpoint to that was, "Okay, tell me how that happens?" since the 7200v lines around here have no neutral carried with them and thus don't seem to be referenced to ground, anywhere. (The secondaries create a neutral by a transformer center-tap, but the primaries have no such tap.)

I made two calls to my local utility provider EIC offices, and he owes me one in return; but what I've gleaned thus far indicates my original off-the-cuff contention is essentially correct. When I get hard data, I'll publish that, along with the name and contact information where it came from.

Interesting stuff. Possibly we can blow another myth apart in the process.

WB2WIK/6
 
RE: Point of it all...  
by K4JSR on August 26, 2004 Mail this to a friend!
Steve, I think "Myth Busters" is already being done!
Although I think Philip would look good with a bald head. large moustache and a beret! I don't know what you look like, Steve. Myth Busters did have a show with some similarities to this thread. It involved a
dead pig. I don't think it was a pole pig, though.

73, and remember, a near myth is as good as a mile!
Cal K4JSR
 
UPDATE  
by KA4KOE on August 26, 2004 Mail this to a friend!
Update:

Called my contact and was referred to a couple of guys in engineering, as he is on the commercial account side and doesn't know diddly about the tech side of things.

When I get time between these two hot projects due next week I'll make some calls.

P

 
RE: Point of it all...  
by WA2TTP on August 26, 2004 Mail this to a friend!
Steve,

I am not a Distribution system expert but I have worked 27 years in Power System Operations involving transmission lines, substations, generating stations etc. I know on the Long Island lighting Co system the 13kv distribution system does use a neutral line. The secondary of the distribution thansformer at the substation ( Typ. 138kv to 13kv) is a "WYE" connection with a grounded neutral at the substation. All the distribution circuits have a neutral wire running under them, which is grounded at many places along the circuit, and the pole transformers are connected from one phase (7200 volts to ground) to the neutral. This being said if the phase wire comes in contact with a grounded object considerable current can flow and the damage can be horrific. The typical distribution circuit breaker in the substation is rated at about 6oo amps but the peak fault current can be in the thousands of amps until the circuit breaker opens which can be may 5 or more cycles (ref. to 60 hz)depending on the current level and then it will, in most cases, reclose automatically with relays that will take even more cycles to trip if the fault is still there. This is done to coordinate with slow blow fuses that are on the circuit. This allows the some of the circuit to remain in service and just the faulted section beyond the fuse to be out.

A "Delta" connected distribution system would not be able to supply any fault current and a phase wire could in theory come in contact with a grounded object and no fault current would flow. Pole transformers in these circuits would be connected phase to phase.
 
Station Grounding  
by K1SL on August 26, 2004 Mail this to a friend!
I would suggest you read the NEC (National Electrical Code) about grounding of receiving and transmitting equipment.
Sam Lollar, P.E.
 
Book about grounding and bonding ( electrical !)  
by CT2ILQ on August 27, 2004 Mail this to a friend!
The US Army Corps of Engineers has available a book
called:

"Grounding and Bonding in Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR) Facilities"

As part of the "HQUSACE/OCE ARMY TECHNICAL MANUALS"
available on
http://www.usace.army.mil/inet/usace-docs/armytm/


The link straight to the book is:

http://www.usace.army.mil/inet/usace-docs/armytm/tm5-690/


73
Paulo Ferreira CT2ILQ
 
RE: Book about grounding and bonding ( electrical  
by WB2WIK on August 27, 2004 Mail this to a friend!
WA2TTP, in my case, the transmission line is 2 conductors, 7200v L-L (phase-phase), no neutral running with this circuit at all. Most L.A. residential service is like this. No netural running pole-to-pole through residential neighborhoods. Exactly two conductors run pole-to-pole, and at every cluster of four homes, the line drops from the pole pig to those four homes. The only other pole wiring is non-power related (Telco, CATV).

As far as I can gather from the EIC office at the local utility HQ (LADWP), the estimated ground fault current should one of the 7200v phase lines break and fall is very small and could be zero. "It's all about safety, and earthquakes," was one statement made.

K1SL, if you have the intestinal fortitude to read through the incredibly long string above, you'll see the NEC issue was beaten to death. If you can find a single paragraph anywhere in NEC relating to grounding the equipment chassis of radio equipment, I'd certainly like to see that reference. Every NEC reference I could find, including those in the NFPA stuff, relates to antenna system grounding. That wasn't the subject here, although that subject certainly deserves its own artical.

WB2WIK/6

 
RE: Point of it all...  
by WB2WIK on August 27, 2004 Mail this to a friend!
Geesh, I mean "article."

And Cal, you're right: Discovery Channel does carry a program called, "Myth Busters."

I've already contacted them about doing a show relating to AC power line hazards or lack thereof, but I haven't received a reply yet.

Steve, WB2WIK/6
 
Another reference  
by KA4KOE on August 27, 2004 Mail this to a friend!
You may want to check out one of the IEEE books, its probably "The Green Book", on grounding. They have a series, ie buff, red, yellow, etc., on various aspects of electrical design.
 
Station Grounding  
by AB5Q on August 28, 2004 Mail this to a friend!
WB2WIK/6 – “If you can find a single paragraph anywhere in NEC relating to grounding the equipment chassis of radio equipment, I'd certainly like to see that reference. Every NEC reference I could find, including those in the NFPA stuff, relates to antenna system grounding.”

How about three and an entire section? When properly interpreted and linked together the information describes proper grounding techniques for radio equipment. Sam (K1SL) our resident PE and others are correct, refer to NFPA 70 or more commonly known as NEC.

Applicable sections NFPA 70 (c1996).

810-71 Transmitters General (a and b).
810-58 Grounding Conductors – Amateur Transmitting and Receiving Stations.
810-21 Grounding Conductors – Receiving Stations (referenced by 810-58) Carefully note (h).
250K Grounding Conductor Connections – Comprehensive section on equipment grounding identification of ground terminals etc. Your radio gear in general terms is considered a piece of equipment.

There’s another reference IAEI “Source Book on Grounding” that I would invite you to skim through if you are still in doubt.

One final note -

WB2WIK/6 - “I've already contacted them about doing a show relating to AC power line hazards or lack thereof, but I haven't received a reply yet.” - Probably because they think that you are a crackpot, my theory.

I’m sorry to hear that you really think that electrical safety is trivial. I have to respectfully disagree with your assessment of the hazards associated with residential 7.2 kV. Treat all electrical circuits with respect and assume nothing is safe.

Regards,
John – AB5Q
 
Station Grounding  
by WA2JJH on August 28, 2004 Mail this to a friend!
One chi must be grounded....otherwise Who cares!
 
RE: Station Grounding  
by WB2WIK on August 28, 2004 Mail this to a friend!
John (AB5Q), actually I've already read those sections of NFPA, and other related sections, along with the EIC of Building and Safety here for the City of Los Angeles.

Interestingly, the City agrees with my interpretation that none of this relates to supplemental chassis grounding for equipment located within residences. As Lloyd said, "If it did, we'd be in serious trouble, since home consumer electronic equipment including your stereo and TV receivers fall under the same category and none of those appliances have any provision for supplemental grounding."

Indeed, most of those appliances have 2-wire power cords that don't even carry a ground conductor. And indeed, the NFPA codes involve grounding the antenna conductors, along with everything else, via a single point ground common to the service utility ground -- outside the home. Thus, your typical TV or stereo, which are the same category of receiving apparatus as amateur radio equipment, have "antenna" ground provisions, and -- alas! -- zero chassis ground provision. As it should be, because they don't need any, even though many television receivers contain high voltage power supplies at far higher potential than commonly found in high-powered amateur amplifiers.

Don't attempt to re-write code on my behalf; others have tried. It won't work, my friend.

I don't encourage anyone to joke about the hazards of utility transmission and distribution wiring and components. That also has absolutely nothing to do with this article. A home and its wiring, inside and outside, are either safe or they're not. Adding an amateur radio station to the mix doesn't change that, usually. In fact, I'd love to hear from anyone who can provide a single example where adding an amateur radio station demonstrably changed anything relating to utility service hazards.

One reason why residential distribution locally is served by delta-connected transmission systems is to keep the lines floating without a ground reference, purposely. Indeed, if one of the 7200v phase lines breaks during the severe vibration of an earthquake, it can fall safely to the ground and lay there for a long time without creating a significant hazard to passersby.

Possibly those who have never lived in L.A., or anywhere with frequent earthquakes, aren't aware of this.

We learn new things every day...

WB2WIK/6

 
Station Grounding  
by AB5Q on August 28, 2004 Mail this to a friend!
WB2WIK/6 - “actually I've already read those sections of NFPA, and other related sections, along with the EIC of Building and Safety here for the City of Los Angeles”. NFPA what? NFPA develops several hundred publications that have nothing to do with this subject. For clarity sake, refer to it as NFPA 70 or NEC so that we understand which publication you are referencing to in your argument.

WB6WIK/2 – “Interestingly, the City agrees with my interpretation that none of this relates to supplemental chassis grounding for equipment located within residences.” – Unfortunately we don’t have a City of LA representative present on this forum to confirm your claim. So for the purposes of this debate, the reference is immaterial. I agree that certain sections within NFPA 70 clearly differentiate between residential and non-residential installations. However, sections 810-71, 810-58 and 810-21 do not differentiate between the two. How are you deriving your interpretation that these sections are not applicable to residential transmitter and receiver installations?

Lloyd via WB2WIK/6 - "If it did, we'd be in serious trouble, since home consumer electronic equipment including your stereo and TV receivers fall under the same category and none of those appliances have any provision for supplemental grounding." - As you point out not all home electronic equipment have ground terminals as described in NFPA 70, section 250-119. However, most radio transmitting equipment manufacturers clearly state that the terminal described in NFPA 70, section 250-119 is to be bonded to a low impedance ground. Sections 810-71, 810-58, 810-21 plus portions of 250 tell you how to do it. By the way, 810-71 only refers to transmitters not TVs or stereos.

WB2WIK/6 – “Don't attempt to re-write code on my behalf; others have tried. It won't work, my friend”. Where in my analysis of this topic am I suggesting a re-write of specific sections within NFPA 70? I am only trying to point out to you what to do with that chassis ground connection as described in NFPA 70 section 250-119.

Earlier comment by WB2WIK/6 “I've already contacted them about doing a show relating to AC power line hazards or lack thereof, but I haven't received a reply yet.” Latest comment by WB2WIK/6 - “I don't encourage anyone to joke about the hazards of utility transmission and distribution wiring and components.” Do you see a contradiction between these two statements?

WB2WIK/6 – “A home and its wiring, inside and outside, are either safe or they're not. Adding an amateur radio station to the mix doesn't change that, usually. In fact, I'd love to hear from anyone who can provide a single example where adding an amateur radio station demonstrably changed anything relating to utility service hazards”.
What is your point?

Regards,
John – AB5Q
 
RE: Station Grounding  
by WB2WIK on August 29, 2004 Mail this to a friend!
John, I don't see a contradiction, at all.

The Discovery Channel show, "Myth Busters" takes on many normally thought-of hazardous acts and carries them out, to see if the hazards are real or imagined. One episode coming up in September involves lightning. Try to catch that one, I've already seen it.

The relevance of my statement regarding adding an amateur radio station to the "mix" of home electronic equipment and circuits is this:

Most people live in homes wired by others and take safety for granted when they purchase and install electronic devices.

Then, for some reason, the tiny fraction of people who are hams seem to feel that when they purchase and install a piece of amateur radio equipment, somehow that opens the gates for new rules regarding electrical safety. It clearly doesn't. There's nothing in any of our ham gear that is any more (or less) hazardous than the hundreds of other eletronic items we use daily without much thought. And there is no new hazard created by the installation and use of amateur gear, other than the antennas we use which are clearly covered by tons of regulation, some of which is adaptation of "code," and some of which is not.

Also, unfortunately for many who haven't done any research on the subject, many people, including hams, think that "code," including the guidelines written by NFPA over a period of many years, is "law." It isn't that, either. Some building and safety ordinances are taken directly from NFPA code, and many are not. But until the code is written into ordinance, it certainly isn't law; it's a long, cumbersome list of recommendations developed by an independent, non-government and non-regulated agency who benefits every time someone buys a subscription to what they've written.

WB2WIK/6
 
Station Grounding  
by AB5Q on August 30, 2004 Mail this to a friend!
The evidence in this matter is crystal clear so I’d like to conclude this debate with the following facts.

Publication NFPA 70 or NEC section 250-119 describes the chassis ground terminal on your amateur transceiver. Not all consumer electronic equipment has provisions stated in 250-119, therefore the reference is not applicable in those circumstances. However, the typical modern amateur transceiver does provide a NFPA 70, 250-119 ground terminal that is indentified in the instruction manual. Furthermore, sections 250(k), 810-21, 810-58 and 810-71 clearly defines effective grounding techniques as they apply to the ground terminal in section 250-119. These sections are applicable to residential amateur radio station installations.

NFPA 70 is not law, rather it is a set of guidelines to help professionals make educated decisions on matters involving electrical safety. NFPA 70 provides the opinions of many contributors and has been successfully interpreted and applied for years. Although NFPA 70 does have commercial interests, it in no way impacts its effectiveness.

The usefulness of a properly installed station ground is really not a difficult concept to understand. Its purpose is not to provide an immediate performance enhancement; rather it serves as an extra level of protection against single point system failure. One should never count on a primary protective device to remain 100% functional indefinitely. Careful system design, with periodic system evaluation and secondary protective measures greatly reduce the probability of a catastrophic system failure. Therefore, a properly designed secondary control such as a station ground provides an extra level of protection against unforeseen circumstances.

Regards,
John – AB5Q - SK
 
Station Grounding  
by N2KOF on September 20, 2004 Mail this to a friend!
I read this article with a great deal of interest. My ham radio experience has only been in New York City. My "shack" is a desk in my bedroom with an old Icom 730 fed through an antenna tuner to a mobile Hustler wip antenna that is installed on my twenty-sixth floor balcony railing with a quick disconnect. I seldom use more than 50 watts and have worked the world. My station is grounded to the cold water pipe of the in- wall air conditioning unit of my apartment. Now I'm wondering if this is doing more harm than good in terms of maximizing the efficiency of my station. Any comments would be greatly appreciated. 73, Jeff (N2KOF)
 
RE: Station Grounding  
by JCRD on September 27, 2004 Mail this to a friend!
Great article, really pleased I don't have to go to the trouble of grounding my new shack in its first floor location.

I've read about half of the replies but still can't find a definitive answer to one thing in particular - I have a pole on the side of my house that isn't grounded, with my VHF/UHF verticle on and the coax coming into the house. Should this pole be grounded for potential lightning strikes or not? The original article says yes, but others seem to suggest not and I'm a little unsure.

Regards,

James
 
RE: Station Grounding  
by KC0OIG on October 6, 2004 Mail this to a friend!
I have a question regarding antenna grounding. Now I have only been an amateur radio operator for 2 years now, and I only hold a Technician class license(soon to be taking my General exam). Ok, here's the situation. I live in a townhouse and the association has strict guidelines for antennas, basicly no antennas on the outside of the building. So I have all of my antennas mounted up in my attic(1 vhf/uhf vertical, 1 2M Loop, 1 6M Ham stick, and 1 HF Dipole). There is not really any concern for lightning, but I have heard that grounding your antennas will cut down RF interference. I designed a plan to ground my antennas but I have second thoughts about how or if it will really work. I bought an 8ft copper grounding rod and a lenght of copper braid(#6). My plan was to drive the rod into the ground and clamp one end of the cable to the rod and run the cable up the side of the house and into the attic, where I would clamp the other end of the cable to another copper rod, piece of copper water pipe, whatever. Then I was going to ground my antennas to the copper rod/pipe in the attic, but I am not quite sure how I am going to do that. Any thoughts or suggestions on how I should do this before I get started, or is it just a waste of time and money.

Thank you and 73,

Brian
KC0OIG
 
Station Grounding  
by OCEANARADIO on October 14, 2004 Mail this to a friend!
Quite an interesting article, Steve. Your experience WRT RF grounding is a bit controversial, o.k.

But your comments on grounding for lightning protection are so seriously innaccurate, they are dangerous. One of the worst was: "The only thing I'll say is, “Equipment (chassis) grounding is not helpful with regard to lightning protection.” And that fact ought to be self-evident to anyone who understands electricity." end quote.

Sadly, hams do not understand electricity at all, if this is your evidence. Please read the NEC-70.250 and NFPA-780. The new October 1, 2004 edition of NFPA is published. Even if you have survived your lack of understanding there, young folks who listen to you might not.

Bonding all equipment individually to a single point station ground is the most important part of lightning protection. The station could survive a direct hit (without exploding, anyway) even if there was no ground at all, but there is no grounding scheme that can make up for lack of or improper BONDING.

One contractor states in a follow-up comment that "nothing can protect from a direct strike". This belies little reading, and even less real life experience. Lots of stations operate through direct strikes. Damage, when it happens, is always traceable to a weak link in the engineered protection plan. Lightning *finds* the weak link, but it doesn't create one!

Most of the commenters seem to understand that ground is not always ground, and could in fact bring deadly voltages into their shack. This seems to be your permanent opinion on the matter, and lacks the knowledge of how proper bonding, including to the AC service mains, prevents high voltage from becomeing high current. You were correct in describing how impedance rises dramatically over just a few feet of distance from the main. But not as fast as the home's ground wiring does, and that is how GPR (Ground Potential Rise) comes up into a station, through connected equipment, and back out via the house wiring to a lower potential ground somewhere else. But that is EASY to beat! With knowledge, careful planning, and attention to details, that is.

Damage this contractor witnessed to a station designed to "float" - means it did NOT float! This is so simple it is almost funny. Almost deadly would unfortunately, be more accurate.

Most commenters also realized that disconnecting *before* a storm means everything: phone, AC power, coax, etc. One or two posters also realized that the mason-jar concept is a plan to return glass to it's more fundamental elements, albeit over a wide area.

Consensus was generally in agreement that lightning protection is an all-or-nothing concept. They are correct. Either protect everything, or disconnect everything. The old "Walk on left side of road, o.k. Walk on right side, o.k. Walk in middle...SPLAT".

If someone intends to protect certain things and not others, sometimes that's o.k. Grounding a rooftop mast via good lightning downconductors to a ground rod should never be overlooked. If that's all you do (unplugging everything inside for a storm), then at least you still prevented a direct or flash-over strike from blowing your roof off and burning down the house. Good job. But I hope your coax was either thrown outside or shorted to the same ground, and AC disconnected inside.

Bonding, surge protection and grounding, taken as a whole, make a total engineered lightning protection plan. All paths in and out of a home, station, antennas, masts, etc., must be considered. Electro- Magnetic Induction (EMI) onto home and station wiring and power surges from outside utilities (yes, even water lines!) are part of this path-study that must be done to protect the station. Few amateurs have the desire or requirement to hire proper and competent design and construction of such protection. But some do, and to a few of you that helped me get there, my hat's off to you.

I operate a USCG Auxiliary HF communications station under all-weather conditions. While I have not had a direct strike, on several occassions trees less than 50' away from my station have had parts blown off, fences have been shattered, and neighbors on three sides experienced damage. Major powerline surges have been handled by the surge protection systems and no damage resulted. If you want to see how I do this, about an hour long read lies ahead of you, and hopefully many hours of study of the National Electrical Code, National Fire Protection Association and boks on "Grounding and Bonding". Whether you read those or not, hiring a Professional Engineer who specializes in lightning protection is worth a hundred books and a thousand internet opinions. In fact I read over a thousand internet opinions (all hams of course) that have almost that many incorrect assumptions about lightning. It's a fun subject and everyone likes to talk about it. Too bad it remains so elusive to so many, as there are such simple principles involved in saving lives and property, if they were only followed correctly.

Here is my system and the engineering behind it:

http://members.cox.net/pc-usa/station/grounding.htm

73 to all who participate in this great thread,

Jack
Virginia Beach VA
 
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