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Author Topic: Copper pipe ground bus - QST article?  (Read 32840 times)
N3QE
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« on: February 06, 2015, 05:48:55 PM »

Right now I'm just hose clamping wires to a copper pipe ground bus. I seem to recall a QST hints-and-kinks style method, of cleverly attaching ground wires to a copper pipe to make a station ground bus. Something like bonding threaded studs through it or into it. Does this ring a bell with anyone?
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K9MHZ
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« Reply #1 on: February 08, 2015, 11:08:57 AM »

If you have a 100-watt soldering iron, that will be enough heat to flow solder onto the copper pipe so you can solder your ground straps right to it.  I use braided straps to each piece of gear, then ran them to the 2-foot pipe mounted to the rear of the (wood) desk and secured them with hose clamps.  Then I trimmed the excess braids protruding through the clamps, leaving a half-inch or so to be soldered to the pipe.  After soldering, each was nicely secured, bonded, and cut to exact length.  The strap leading to the ground system was secured and bonded in a similar fashion.

  
« Last Edit: February 08, 2015, 11:11:34 AM by K9MHZ » Logged
KD8IIC
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« Reply #2 on: February 08, 2015, 11:04:43 PM »

 Yes and it works fine. I used wire ties to attach the tubing to my metal shelves and used small diameter hose clamps to secure the flat braided ground straps to the tubing. Easy and quick plus you can adjust the position easily.
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KD0REQ
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« Reply #3 on: February 09, 2015, 09:37:05 AM »

I went fancy and cut the bottoms off some plastic goblets from the botique Tarzhay.  epoxied them into a piece of 3/4 copper M tubing.  brackets hold that off the wall behind the rigs.  used Ideal hose clamps to stick down the braid to the rigs on it after a stout Scotchbrite polish and coating the copper with Vaseline so it doesn't oxidize.  inside station ground is now solid.
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N3QE
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« Reply #4 on: February 09, 2015, 09:44:38 AM »

Found the QST article I was looking for; July 2014 Hints and Kinks, page 65, "An Improved Ground Connection" by WA3KBD. He flattens the pipe a little bit, drills through holes to allow a longish brass screw to be put through, tightens a nut, then solders the nut and screw in place to the flattened surface. This serves as a stud for attaching ring lugs.

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AF5MS
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« Reply #5 on: February 19, 2015, 01:16:46 PM »

I plan on using the copper pipe, but was going to take a different approach on attaching the various ground wires to the pipe.

When needing to attach/detach the ground wires, I will not be able to stand long enough to unscrew anything.

I bought a number of the 50 amp Gardner-Bender alligator clips. The stout spring ensures a firm grip on the 1/2" pipe, yet can be quickly removed.

http://www.gardnerbender.com/en/14-550

Thoughts?
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Mike
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K9MHZ
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« Reply #6 on: February 22, 2015, 10:41:53 AM »

MS....

Just wondering about any corrosion amounts between the dissimilar metals?  Probably not an issue if you're in a dry environment (low humidity), but it reminded me of guys who use power poles who have to jiggle or disconnect then reconnect them every so often, just to break up the small resistances between the conductors in the connectors.

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AK4SK
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« Reply #7 on: February 23, 2015, 10:30:16 AM »

I've read in a few places that using a ground bus is a bad idea because it can create ground loops between pieces of equipment. The suggested solution is to connect grounds to a single point where the outside ground enters the shack. The January 2015 issue of QST has an article that talks about grounding and it mentions a ground bus. The ARRL handbook briefly mentions single point grounds (although not as a necessity) and I think one of the ARRL study guides I used for one of my tickets did also.

It seems that using a ground bus is not causing any problems. I'm currently using the single point ground setup so I have several 1/2" tinned copper straps running from my equipment to my entrance ground. A bus would make things much cleaner.

73,
Chris
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K1PJR
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« Reply #8 on: February 25, 2015, 09:46:45 AM »

I'm still don't understand why equipment must be grounded. We know there are three types of grounds: RF, electrical and lightning.  I would assume using a ground bus helps for lightning protection but if your antenna were struck by lightning I would think your equipment is toast with or withour a ground.  I've read pro and con on this.  The ARRL handbook says not to ground equipment if your shack is on a second floor (which mine is) so I don't use a ground on my equipment.

Can someone shed some light on this?

Phil
K1PJR
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K9MHZ
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« Reply #9 on: February 25, 2015, 02:59:23 PM »

Chris,

I think the ground bus vs. single point deal is one in the same, so long at the bonding to the copper pipe (or whatever) is uncompromised with no resistance at the junction points.  For our purposes, the bus will probably be so small in sheer size, that it's almost single point anyway.  The biggest thing though, is to get each of the straps going to the equipment bonded solidly to the pipe without any chance of any connection resistance due to minute corrosion, etc.

 
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K9MHZ
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« Reply #10 on: February 26, 2015, 05:06:23 AM »

REALLY good explanation in the new (March 2015) QST.  He even goes into cable physical layouts to prevent common mode coupling.  He likes the bus idea, BTW.

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AK4SK
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« Reply #11 on: February 26, 2015, 06:27:33 AM »

REALLY good explanation in the new (March 2015) QST.  He even goes into cable physical layouts to prevent common mode coupling.  He likes the bus idea, BTW.



Thanks for the reply, I'll take a look at QST. A single point ground in practice may be the same as a ground bus, at least for ham purposes. I really don't know (hence the question). But in the examples I've seen in clearly shows that they are different and that the single point ground is preferred. See the first two figures on this site: http://kc.flexradio.com/knowledgebasearticle50426.aspx

The ARRL Handbook also shows a single point ground image similar to this. However, the Handbook is worded in a way to say that for ham purposes a ground bus is adequate but that a single point could be used to solve a ground loop problem, IIRC.

Again, I'm not trying to say one is better than the other or even different, I'm just pointing out that some people believe there to be a difference.

73,
Chris
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AK4SK
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« Reply #12 on: February 26, 2015, 06:56:59 AM »

I'm still don't understand why equipment must be grounded. We know there are three types of grounds: RF, electrical and lightning.  I would assume using a ground bus helps for lightning protection but if your antenna were struck by lightning I would think your equipment is toast with or withour a ground.  I've read pro and con on this.  The ARRL handbook says not to ground equipment if your shack is on a second floor (which mine is) so I don't use a ground on my equipment.

Can someone shed some light on this?

Phil
K1PJR

The February 2015 edition of QST briefly mentions the three different kinds of ground you mention and why they're all needed. When you state that you do not understand why equipment should be grounded are you referring to all three types of ground you mention, or just one or two of the three? I believe I'm correct in saying that a ground bus (at least in the context mentioned in this thread) is just a method of providing an RF ground path for your equipment. As such it is not intended primarily to offer lightning protection but under certain circumstances it may function to protect equipment. There is no way that I know of to ensure completely lightning protection for your equipment but I may be wrong about that. Even so I take all measures that I think are adequate to protect my equipment from lightning. I also disconnect my equipment when there is a chance of a thunderstorm (this is debated also), for me that is almost everyday during the summer.

I have a 2nd floor shack and I use an RF ground. I generally don't have any issues but the long ground connection can be problematic with certain antennas.

What edition and on what page of the ARRL handbook does it state not to use an RF ground on the 2nd floor? I'd like to read that section.
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VE3TMT
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« Reply #13 on: February 26, 2015, 07:14:46 AM »

I don't ground my equipment, never have. In 25 years of operating I have never had any problems. The only ground wire in my shack is from my PC case to the ground stud on the back of my transceiver. Even running 600W, I get not RF anywhere. the ground wire between the PC and radio eliminated a bit of hum I was getting on the PSK line.
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KK5DR
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« Reply #14 on: March 20, 2015, 08:04:03 PM »

I used a length of 3/8s inch ID copper tubing for station grounding once. It had several wire "straps" soldered to the tubing spaced equally. It worked fine.
Now I use a single point grounding for the station. A thick copper round plate with heavy braided copper straps that connect the gear to the plate, which is connected to the outside ground rod directly with a single run of 6ga wire.
You must also understand that station grounding serves only two functions. 1. RFI suppression and prevention. 2. Electrical safety grounding.
It is NOT lightening protection. No grounding system in existence can protect your station during a direct lightening strike. Even a nearby strike can induce huge voltages in your station ground system and damage the gear.
I disconnect my station from outside grounds when the station is not in use. Isolating the station from the outside world has protected it so far from several nearby strikes that damaged TV gear in my house. There was no damage to any ham gear.
I re-connect the ground when I'm operating the station. I made it easy, I use a large alligator battery clip that connects a heavy copper braid from the station single point ground plate to an outside grounded plate mounted on my shack wall, well away from my gear.
So far, no RFI, no RFI issues of any kind. No electrical problems, ground loops, etc. My deactivating protocol has protected my gear from numberous nearby strikes.
I think it works.
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