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Author Topic: Why am I supposed to make a second ground connection? Isnt this a ground loop?  (Read 1108 times)

W9WQA

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Now, my transceiver does have a separate ground lug.  So now why am I supposed to run a ground braid from my radio through the wall to this post???  Wont my radio then have TWO separate paths to ground?  I thought that was a nono.

Absolutely will put you in a ground loop, a very dangerous and noisy ground loop. Most5 hams place themselves in a ground loop intentionally like you are going to do. Why, because codes, best practices and physics do not apply to ham radio operators. Hams just make it up as they go along.

Where you and most all hams go wrong is you intentionally do not comply with electrical codes, especially NEC 250.94. You failed to bring your lines in where the AC service enters creating a single point ground. All other providers learned this long ago and why it is written into electrical codes. Your CATV, Telephone, and TV antenna installers must comply, they have burned down to many houses and equipment.

So don't worry about, take your chances and ignore codes. While you are at it make sure to put your mobile radio into a ground loop by connecting the radio dc negative directly to the battery. Guaranteed to have a lot of noise, and someday when you start the car, burn up your radio power wiring and coax.

Absolutely will put you in a ground loop, a very dangerous and noisy ground loop.

? please explain details of this 'very dangerous and noisy ground loop."
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W6BP

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Are you really creating a ground loop? Does that lightning arrestor (which I'm guessing uses either spark gaps or gas discharge tubes) have a path to ground when it isn't conducting a lightning strike?
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AI5BC

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Absolutely will put you in a ground loop, a very dangerous and noisy ground loop.
? please explain details of this 'very dangerous and noisy ground loop."
OK that is the right question to ask, and the answer is very basic electrical principles. Before i answer we have to bust a myth. Ground rods are at Zero potential is false. If you drive a ground rod in spot A and Drive another ground rod at spot B, the two rods are at a different potential. You can measure with a voltmeter and see a lot of noise if you use an oscilloscope. You will see both AC and DC voltages.

Your AC Service is at one potential, and your station ground is at a different potential with your radio and house wiring being used as a conductor to bond the two together. Simple Ohms law at play, you are driving outside common mode current through your equipment ground plane. What do you call unwanted voltages and currents = Noise.

When you transmit, the ground loop you created acts as an antenna and magnetically couples with your antenna likie any simple transmitter and can cause all kinds of RFI and EMI problems.

OK that is the noise problem you created for yourself, now let's get to the danger part. You need to understand Step Potential that i just described, and now apply lightning. Lightning is a surface charge that spreads out laterally from the point of entry into the earth. Dirt is an extremely poor conductor and when you run thousands of amps the ground with 100's of ohms per inch develops many thousands of volts between any two points. Simple ohms law.

The term Step Potential refers to the distance between your feet is enough to kill you. In fact, up to 20 or more people with a single strike. Lightning did not strike any of the people, it strikes a structure, and as the lightning discharged accross the surface, the voltage developed between their feet killed them.

So, what do most hams do, they ignore code and listen to Elmer using practices from the 50's. Your AC service is at one potential, and your adio is at another potential. Guess what connects the two together, your house wiring and radio coax. Lightning strikes and you get exactly what you asked for, BOOM!

Ground is stupid simple and here is what is taught to technicians and engineers, and electricians. You bond everything underground together to form a common ground electrode system.  Then you bond everything above ground called your equipment bonding jumpers. The you bod the two systems together at one point only. Make a second connection and you loose your liscense ande the customer loses his equipment and possible their life.

With a Single Point ground all your equipment is at the same potential. Go back to Ohms law 0 volts / 0 to infinite Ohms = 0 Amps all day long.  What you need to understand is your home is intentionally designed as a single point ground. Code requires it. The single ground connection is right below where your AC service enters. Stop running your coax directly to the shack. You can supplement your AC service ground beyond the two-rod minimum if you want.

Last thing I will mention is ground rods are for POWER frequencies, and radial, bare solid copper are for lightning and high frequencies.  That is why professionals use a ground ring and radials to discharge the lighting and direct it away from the protected area. Hams intentionally invite lightning and noise inside.
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KA4WJA

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Richard, AK4YA,
I agree with Greg here....reading Ward Silver, N0AX's, book will answer all your questions here!
It is a very good investment!  (particularly for a ham in the SE U.S., where lightning can be an issue....and especially for a new / newer ham!)

https://home.arrl.org/action/Store/Product-Details/productId/133989

I'd suggest picking up a copy of the ARRL's Grounding and Bonding for the Radio Amateur. It can explain why all radio gear should be grounded to a grounding rod way better than I can.

And, while you're waiting on the book to arrive, take an hour or two of your time and watch one or two of Ward's seminars on "grounding and bonding"...
FYI, as you'll see Ward is one of those EE's that can actually teach / help his fellow hams!  :)

(yes, he does recommend reading and using NEC, etc....I can tell you that even someone like me, who has been using the Motorola standards/recommendations [R56] for decades now, can learn something from Ward's book!)

https://www.youtube.com/watch?v=4RkiRwjK2oU&t=35s

https://www.youtube.com/watch?v=JHs46k3TxsU

Then....STOP...
And, have a glance at the Motorola Guidelines while waiting for the book to arrive....

And, please ignore the arguments going on here-abouts.  :)


I hope this helps?

73,
John,  KA4WJA


P.S.   Although, it's doubtful you'll need to read it, if you want the straight scoop in a lot of detail, you can find the NEC handbook at your library....

But, you can download the Motorola R56 Guidelines here:

https://www.blm.gov/sites/blm.gov/files/Lands_ROW_Motorola_R56_2005_manual.pdf

« Last Edit: October 19, 2022, 02:38:14 PM by KA4WJA »
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WA3SKN

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Ward's book is both pretty good and reasonably priced... I'll just give it a plug and be done with it!
It is worth having in the library.

-Mike.
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W9FIB

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Another thing most people forget is if it is not done according to code, and you do have a fire from a lightning strike, your insurance company will most likely deny your claim. When I had my house fire back in 2015, the first thing the fire inspector looked at was to make sure ALL electrical was up to code. This included all station wiring and grounding.

Trying to cut corners can be a financial disaster, or worse yet, cost you your life. What are you willing to risk to save a couple hundred dollars by not doing it right?
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73, Stan
Travelling the world one signal at a time.

AK4YA

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OK Ive got it all done as suggested, the ground rod outside my shack is bonded to the homes AC ground rod.  And I have all my equipment individually grounded with braid to a copper bar at the desk that is then grounded with #6 wire through the wall to the rod outside the shack.  This rod is also where the antenna lightning/surge device is grounded to.  yay.

But now, im looking at a new radio, one that doesnt have a builtin DC power supply like my FT-897D does.  So I have this PSU to use for the new radio, but the PSU doesnt have a ground lug on it.  So after I replace the radio and ground the new radio with the old radio's ground do I just hook up the NEG and POS PSU terminal to the radio and call that done?  Or do I put a ground braid from my ground bar in the shack to the NEG term of the PSU?  Or do I drill a hole in the PSU's case and put a braid ground from the bar in the shack to the PSU case?
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AI5BC

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All that work and you did not fix a thing. You are still hopelessly lost in a Ground Loop.
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AK4YA

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All that work and you did not fix a thing. You are still hopelessly lost in a Ground Loop.

I literally stand in awe at the levels you appear to be willing to go to specifically so you can be a jerk.

I took your post earlier in this thread as some bit of chastisement/scolding because maybe you felt I was trying to bypass steps and not connect my ground rod outside of my shack to the house AC service ground rod.  So I put on my big boy pants, knowing im but a dumb noob, and connected all as you appeared to be intending me to do, and did so at some considerable cost & effort (its a 150ft run and #6 copper is expensive).  And now this.



Your incessant posting of sanctimonious jackwagonry and self righteous nonsense proves beyond a shadow of a doubt that indeed sometimes the slowest sperm does fertilize the egg.

While you may fancy yourself some sort of a Christian, I am sure Christ would gleefully leap off the nearest bridge in order to disassociate himself with your holier-than-thou crap. All I can think of when my eyes are burned with the continual lack of quality content of your posts and moderator brown-nosing is that another 4 minutes of my life could be potentially wasted should I make the mistake to read whatever you have written.

You have dirty clothes, BO, bad breath, and I am quite confident that should one open your top dresser drawer, it would contain skid marked underwear. Your children will grow to be nothing more then felons or beggars due to their genetic lineage. Likely, even your car is a smog machine, and pollutes the earth like you pollute this site. You are a festering infected boil on the tail end of ham radio; with the apparent intelligence of an autistic gnat with downs syndrome.

You are the type of weenie that causes people of mutilate themselves, trying to escape the emotional pain that people as worthless as you even exist. Knowing that you are licensed, I am strongly leaning towards supporting continually-more stringent testing for licensing. The fact that a man who can't even grasp the insane hypocrisy that exists in your constant barrage of self-sainthood is allowed to own a habiliment of destruction is a social calamity, and needs to be stopped. You cry like a woman, and you have a night-light to fend off boogie men. You dress in drag, and you listen to ABBA. I am guessing that early in life, Hitler encountered the Jewish version of you, thus explaining his future actions. I wish you nothing less then painful pancreatic cancer, stones in your shoes on long walks, and blisters on your rear as you sit down on the toilet. Sleepless nights, broken hearts, hurricane damage to your home, sadness, pain, misery, Out of the Closet outspoken homosexual children, traffic tickets, loss of loved ones, felony convictions for crimes you didn't commit, weight gain, stubbed toes, sprained limbs, damage to the transmission of your car on the ONE DAY you really needed it, always having something in your eye, having to smell other peoples farts in elevators, long waits at traffic lights, getting laid off from your job, medical bills, having a squib load, then firing a round after it, holes in your socks, underwear that's too tight, impotence, limb amputation, or any other possible iniquitous event that could harm you as bad as your mere presence harms humanity as a whole.

I believe elimination of infertile jerks such as you could bring everyone on this planet of differing views together, for the sole purpose of your eradication. You are living proof that humans can impregnate rodents. I hate you.
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N2ZYI

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OK Ive got it all done as suggested, the ground rod outside my shack is bonded to the homes AC ground rod.  And I have all my equipment individually grounded with braid to a copper bar at the desk that is then grounded with #6 wire through the wall to the rod outside the shack.  This rod is also where the antenna lightning/surge device is grounded to.  yay.

But now, I'm looking at a new radio, one that doesn't have a built-in DC power supply like my FT-897D does.  So I have this PSU to use for the new radio, but the PSU doesn't have a ground lug on it.  So after I replace the radio and ground the new radio with the old radio's ground do I just hook up the NEG and POS PSU terminal to the radio and call that done?  Or do I put a ground braid from my ground bar in the shack to the NEG term of the PSU?  Or do I drill a hole in the PSU's case and put a braid ground from the bar in the shack to the PSU case?

I'm here for this same exact information. I know the Yaesu FP-1030A has a ground lug on the bottom but I went with the FP-1023 for now (no ground lug as far as I can see). I have the braid lengths for both radio and PS. Unscrew a cabinet cover and attach the ground braid as you are suggesting was my idea as well. 

Scott
N2ZYI

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AI5BC

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I literally stand in awe at the levels you appear to be willing to go to specifically so you can be a jerk.
To get your attention. I will say it again, you are still in a Ground Loop. You are still in between two earth grounds. The one you mistakenly placed outside the shack, and your AC service ground. Your radio and house wiring are still between two grounds placing you in ground loop. All you did was make a very expensive parallel circuit that did nothing except bring you into compliance with NEC 250.58 common ground electrode requirement. You failed to comply with 250.94 Inter-System Bonding Terminal (IBT) requirement. The very foundation of a single point ground to prevent you from putting anything in a ground loop.

You said your home is new construction and met NEC codes. If that is true, you have an IBT installed right where your electrical service enters. Real easy to find and identify. It is the terminal the telephone, CATV, SATV, and ISP provider ant there surge protector ground wire to right before the service enters the house. Everything uses a Single Point Ground including your home AC wiring as code requires.

To fix the mess you created, follow code and best practices, and quit listening to boomer elmer. Codes and trade schools make it very simple to understand with pictures. Here is what you do.

1. Reroute your coax from the tower to the IBT at your service entrance. Bond your coax surge arrestor and or coax shield to the IBT, then take your coax inside to the Schack just like every other service that enters. You can run it on the outside of the house if you are lazy, but do not ground it anywhere along the way.

2. Yank out that ground wire you are using for a station ground running outside to a ground rod. You have no use for it and keeps you in a ground loop. Install a new Station Ground Wire. It originnates or starts at th eIBT, the exact same point everything inside originates from. run it inside tightly coupled to the coax or coaxes. Then means zip tie them together. Use at least 6 AWG copper insulated wire. Once inside terminate the wire to a busbar and call it Station Ground. Then run dedicated jumpers for each piece of equipment with a ground lug. DO NOT use station ground on anything with a 3-wire AC power cord like your DC power supply, they already have a proper dedicated ground that originates from the exact same point as your toys. Your
Station ground is what pros call a DC Equipment and Safety Ground for your low voltage toys.

You can leave the copper you already buried. If you had done this correctly in the first place, you could have avoided all that time and expense. There is no problem supplementing your homes ground electrode system, but smart money would run bare copper wire called a radial electrode away from the house to direct lightning and high voltage utility away from the protected area.

Chew on that rag.

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AK4YA

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To get your attention. I will say it again, you are still in a Ground Loop...

ok thanks much for this detail...  you seem to be confirming exactly what I suspected in the title of this thread which was "Why am I supposed to make a second ground connection? Isnt this a ground loop?".  I thought that following all the elmer recommendations (including nearly all the well-respected YT ones Ive watched so far) would create a ground loop.  You have confirmed this thanks!

In my case though there is no coax at all except the 1ft length between the radio and the balanced tuner.  My antenna is fed with windowline and connected to a balanced surge/lightning arrestor https://www.dxengineering.com/parts/dxe-llsp  right outside the house.  The surge arrestor is currently connected to that ground rod just outside my shack room.

Now, like I described, the AC service entry is on the exact opposite side of the house.

So finally, here is where Im lost.  My homes AC service main panel bonded to the AC main service ground rod.  The AC outlet where my radio gets its power has a ground wire going to my AC panel which is bonded to that ground rod.  What is the point of running a parallel line from the AC main ground rod to my radio???  (Isnt this STILL a ground loop with 2 different paths to the ground?)
« Last Edit: November 20, 2022, 02:49:27 PM by AK4YA »
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WW5F

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AK4YA - wow!  Sometimes I think those thoughts about some posters.  You actually put it in writing!  Thanks.

Simple answer to your last question:  yes

Long answer:  grounding and bonding is a "science".  And since the variables of atmosphere and earth are involved in this science, there is no *one* correct answer for everyone.  Even the idea of pounding a ground rod into the ground, engineers have to "imagine" a "cone of influence" around the ground rod.  And because my dirt is different from your dirt, the actual ground "reference" is going to be different.  Connecting them all together makes the ground reference the same (but still varies as you move down the wire!)  This is *one* of the reasons why you always get more than one correct answer (and sometimes absolutely stupid answers) in forums such as these.  I came to this realization a few years ago.

I pounded 7 ground rods into the dirt around my shack.  Using "one-shot" welding pots and 8 gauge wire, I "bonded" them all together, in a line, starting at the power panel ground.  Three of those rods are clamped to the bottom of some telescopic masts to support my wire antennas (path for lightning).  ONE INCH braid comes in from one of those ground rods to my "ESD workbench".  The last ground rod continues that 8 gauge wire into a ground bus across the back of the desk where I have my ham gear.  I also ran a ONE INCH braid to that same ground bus.  Then I realized there was a ground loop or two because of the neutral and ground wires in the outlets I was plugging my ham gear into.  (Isn't that neutral and ground wire in the power wire a ground loop in ITSELF!? -- YES!  One is for the RETURN of power, the other is for SAFETY.)  So I'm living with some ground loops.  It works.  I can always find someone to say (especially in here) I'm doing it wrong.  One thing I consistently hear is the "shortest path to ground" is the safest.  So screw it.  It's staying as is.

Depends on what kind of grounding system you're talking about:  ESD ground, Safety ground, Lightening protection ground.  And these go by other names, too.  And chances are your grounding system is for more than one purpose:  at least, as hams, lightening protection and personal safety!

As long as ALL your grounds are electrically connected to the same ground as everything else, and it's connected to the ground at your power panel, this is the safest.  Schematically speaking, it should look like a STAR from your power panel ground rod.  Functionally, it'll probably be a BUS from your power panel ground rod.  As long as there's a straight path back to your power panel ground rod, that's the best anyone can do.

(Keeping in mind, this is your house, not a broadcast station where the main design of the building is for that big transmitter.)

https://www.allaboutcircuits.com/technical-articles/an-introduction-to-ground/

...my 2 cents
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AI5BC

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So finally, here is where Im lost.  My homes AC service main panel bonded to the AC main service ground rod.  The AC outlet where my radio gets its power has a ground wire going to my AC panel which is bonded to that ground rod.  What is the point of running a parallel line from the AC main ground rod to my radio???  (Isnt this STILL a ground loop with 2 different paths to the ground?)
No, not at all; the green wire in your wall receptacle is a dedicated AC equipment ground isolated from DC equipment ground. You are no longer between two earth grounds; you have a single-point connection to the earth.

A common myth is ground rods are at zero voltage—complete BS. If you drive a ground rod and then another rod some distance away, you will have a voltage difference between the two rods you can measure with a DVM and oscilloscope. Connect an oscilloscope to measure lower power frequencies, and you will see 60-Hz because the utility uses the earth as a return conductor using a multi-grounded neutral distribution system. Turn the sweep speed up, and you will see a mish-mosh of noise from cosmic radiation.

Most hams bring the coax directly to the schack, sink a rod or two, and bring it inside. Then you use your radio system to bond the two ground systems together. You do not have a ground because you are in a ground loop, a series of daisy-chained grounds. Your radio system is just a wire bonding the two ground rods together. Those two rods are at a different potential acting as a signal source driving common mode current through the equipment ground plane. Every piece of equipment has a difference of potential because it is a series connected to ground with a common mode current flowing through the equipment ground plane. Could you think of how it is all connected? Your coax enters and carries an earth ground on the coax shield from the rod outside the shack > shield of the coax to tuner chassis > tuner chassis to radio chassis > radio chassis to DC negative > DC negative to DC power supply chassis (you can fix that) > DC power supply chassis to AC equipment ground, AC equipment ground to AC service ground connection. It is a series mess connected in a daisy-chain fashion. Each series segment, coax shield, equipment chassis, or conductor has a series impedance with a common mode current flowing through it from external forces. Simple ohm s law; current x resistance = voltage. Every piece of equipment is at a different potential.

That is just a nuisance in normal operations, especially when you PTT and that long bonding jumper you ran through your house is within two wavelengths magnetically coupled to the antenna, giving you many common mode current problems to fix. The real problem is the danger you have placed yourself in. You need to read up and understand Step Potential created by lightning and utility high voltage faults. When lightning strikes and enters the earth, it discharges along its surface laterally, like throwing a rock in the water. As the currents flow through dirt, a voltage gradient is developed along the way called Step Potential because the distance between your feet is enough to kill you. Depending on the strike's intensity, 1000 to 5000 volts per foot. How far apart is your shack ground from your service ground? How many volts are across your radio system, and how much current is flowing? The answer is 1000's. For current to flow, there must be a point of entry and a point to exit. You provided a path through your home for lightning to enter and exit—the Father of common mode current.

Back to your question: Yes, you need a dedicated ground conductor for the Station Ground; it is required and cannot be the AC equipment ground from a receptacle. You would lose isolation between AC and DC systems if you did that. You need a dedicated station ground conductor for two reasons: Safety and Operational. Starting with safety, NEC requires electrical systems to be isolated, like AC and DC power systems. The reason is simple: if there is a line fault to the ground in one of the systems, the fault current is contained in that system and not the other minimizing electrical shock and equipment damage. Code requires both systems to have a common ground point in the event there is a cross-system fault, AC to DC to provide a PLANNED FAULT path back to the source. Your radio system is a 12 -Volt DC low voltage system and requires a dedicated DC Equipment Ground, aka DCEG. Convert that to ham lingo, your Station Ground.

Operationally this is where hams get lost in elmer's tall tales. AC ground is dirty is a half-truth. The AC Service ground is NOT DIRTY; the AC Equipment Grounds, aka ACEG, can be dirty (noisy). The AC service ground is misunderstood; it is the point where the AC service is bonded to the premises ground electrode system, aka GES. It is a single-point connection via a specific conductor called the ground electrode conductor, aka GEC. The GEC is the conductor running from your service disconnect device like a meter can straight down to the GES. It is the GES you may want to supplement because Mr. Sparky did the code minimum; he drove two ground rods 6-feet apart, collected a check, and called it a day. The best practice is to run a solid, bare, tinned, 6 AWG minimum copper conductor in the same trench as the coax below it as deep as possible to the tower. Otherwise, run away from the house or protected area to direct lightning away. Rods are for power frequencies; radials are for lightning, and longer is better. 

ACEGs are the third wire run with your AC branch circuits to wall receptacles, and the ACEGs originate where the GEC is bonded to the Service Neutral Conductor inside your service disconnect device. So how does the ACEG get noisy or dirty? Again, it is straightforward. All equipment plugged in has passive electrical devices installed between Line to ACEG and Neutral to ACEG to meet FCC requirements and over-voltage protection. For example, line filters, PFC correction circuits, capacitors, gas discharge tubes, SADs, and MOVs. That dumps RF and low-level 60-Hz line current into the ACEG, corrupting the ground circuit. Ever heard a hum in PA speakers? The best solution to MINIMIZE the problem is to run dedicated AC branch circuits to the shack. You will not have upstream or downstream receptacles daisy-chained together, adding to the noise. If there is any noise on the ACEG, it is because whatever you plugged in generates it. All your home branch circuits have dedicated and isolated ACEGs, so noise or a fault in one circuit will not interfere with other branch circuits.

So yes, you want your station ground to originate where your AC service ground originates, the same single point that all ground systems originate from. Your earth ground, lightning ground (antenna discharge units), AC ground, and DC ground all connect at the same point. The DCEG and ACEG that go inside are an open circuit going nowhere. The best place is to tap the GEC as close as practical to the service disconnect device. Everything at the same volage potential. with no current flowing. A ZERO-VOLT reference POINT. If there is no voltage or current = no noise and safe.

How is that for a Jack Wagon?
« Last Edit: November 21, 2022, 12:42:36 PM by AI5BC »
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W9WQA

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Now, my transceiver does have a separate ground lug.  So now why am I supposed to run a ground braid from my radio through the wall to this post???  Wont my radio then have TWO separate paths to ground?  I thought that was a nono.

Absolutely will put you in a ground loop, a very dangerous and noisy ground loop. Most5 hams place themselves in a ground loop intentionally like you are going to do. Why, because codes, best practices and physics do not apply to ham radio operators. Hams just make it up as they go along.

Where you and most all hams go wrong is you intentionally do not comply with electrical codes, especially NEC 250.94. You failed to bring your lines in where the AC service enters creating a single point ground. All other providers learned this long ago and why it is written into electrical codes. Your CATV, Telephone, and TV antenna installers must comply, they have burned down to many houses and equipment.

So don't worry about, take your chances and ignore codes. While you are at it make sure to put your mobile radio into a ground loop by connecting the radio dc negative directly to the battery. Guaranteed to have a lot of noise, and someday when you start the car, burn up your radio power wiring and coax.

silly nonsense
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