+++++++++++++++++ Date: Mon, 07 Oct 2002 10:09:23 -0500 From: "George, W5YR" Organization: AT&T WorldNet Service To: pjhend at ameritech.net Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] Ground Strap Paul, with all respect, a ground strap 50 ft long will probably cause many more problems that it could cure. If you require an "r-f ground" and are that far from Earth ground, which is always questionable as to its r-f effectivenss even with a short connecting conductor, consider using 1/4-wavelength "driven ground" wires in the shack to place the shack equipment at near zero r-f potential. 73/72, George Amateur Radio W5YR - the Yellow Rose of Texas In the 57th year and it just keeps getting better! Fairview, TX 30 mi NE of Dallas in Collin county EM13qe K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121 pjhend at ameritech.net wrote: > > Anyone have ideas where I can purchase copper groundstap in a length up > to 50'? > Maybe in the Chicago area or order online? Thanks! > Paul +++++++++++++++++ Date: Mon, 07 Oct 2002 10:53:02 +0100 From: pjhend at ameritech.net To: "George, W5YR" Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] Ground Strap George, I will not be running all that far to ground, I need the length to connect roughly 27 linear feet of radios. I'm planning to hop from one radio to the next with ground strap (flattened, soldered, and then the hole drilled through the strap for the ground lug). From there, it's on to the cold water pipe and earth ground only 8' away. Thus, at minimum, I'll need 35'. 73 Paul +++++++++++++++ From: "George, W5YR" Organization: AT&T WorldNet Service To: pjhend at ameritech.net Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] Ground Strap Look at dealers who handle craft supplies and sell copper sheet of various widths in rolls. You will probably have to piece together several pieces to make the entire run. Also building supply houses might carry small rolls. >From an engineering viewpoint, the distributed equipment ground that you describe is not as good as the "star" ground system in which a separate conductor runs from each piece of equipment to a central "ground" point. Sounds like your layout would not permit this, however. The piece of gear at "the far end" can be at some r-f, a-c and audio potential above the piece nearest the actual "ground" connection with the serial layout you want to use. This largely tends to defeat the use of a station ground arrangement in which you want the chassis, etc. of all pieces of gear to be at the same potential. 73/72, George Amateur Radio W5YR - the Yellow Rose of Texas ++++++++++++++++++ From: "Charles Bland" Organization: Entropy Reduction, Inc To: "George, W5YR" , Elecraft at mailman.qth.net Date: Mon, 7 Oct 2002 10:00:31 -0700 Subject: Re: [Elecraft] Ground Strap Reply-To: BlandRanch at BlandRanch.net Paul, Let me second what George has said. What you are proposing has a few problems. First, with a ground system, your goal is to remove voltage surges (lightning, power events) from the equipment rather than distribute them. With this in mind, you want the "star" or "single point" wiring method. With what you are proposing, a "problem" on one piece of equipment will be shared with all of them on your "buss" rather than delivered to the closest ground. Stated another way, a surge has to flow by your other equipment to get to ground. You don't want to do this. Next problem is that you will create a serious single-point failure issue. If you buss fails at any one point in your distribution wiring, other components will be at risk and will be left unprotected. Lastly, this approach runs afoul of NFPA and NEC specs. Bottom line suggestion. Establish a low resistance ground (< 5 ohms), and use a #2 stranded cable to bring your ground to a copper distribution plate. Use #6 (solid or stranded - I suggest stranded, it is easier to install) jacketed wire to ground each piece of equipment to the distribution plate. For great specs, see NFPA 70, NEC Section 250, and a very practical document put out by Motorola called R56, which brings all these specs, practices, and procedures into one document. Chuck - n6dbt +++++++++++++++ Date: Mon, 7 Oct 2002 13:41:45 -0400 (EDT) From: kc4kgu at ENTERZONE.NET To: pjhend at ameritech.net Cc: "George, W5YR" , Elecraft at mailman.qth.net Subject: Re: [Elecraft] Ground Strap Paul, You're looking for trouble "daisy-chaining" your ground. Grounding each radio to a common ground-bus that then connects to your outside ground is the recommended method. 73 de John - KC4KGU K2/100 #2490 ++++++++++++++++ From: "Stuart Rohre" To: , "George, W5YR" Cc: Subject: Re: [Elecraft] Ground Strap Date: Mon, 7 Oct 2002 16:13:40 -0500 Don't forget 8 feet is a quarter wave on 10m. Thus, George's comment certainly applies at 10m band. For that band you can augment the water pipe static discharge ground with a series tuned circuit and 8 foot insulated conductor along the base board of the shack to keep the radios chassis at near zero RF potential. Also, consider the furtherest radio in the chain will have a differing RF ground situation at 10m (and other bands) than the one closest to the 8 foot direct run to pipe. Many modern houses do not have metal pipe outside the foundation, and all the way to the main. In areas here with that problem and with poor ground conductivity, we are burying circle grounds of bare copper wire around the building, to have a common voltage reference in case of lightning surge. With 100 to 200 feet of no.10 or larger wire, you can get an adequate ground buried 18 inches under the surface. When we have solid limestone below that, that is about all we can do. 73, Stuart K5KVH +++++++++++++ From: "Stuart Rohre" To: "George, W5YR" , Cc: Subject: Re: [Elecraft] Ground Strap Date: Mon, 7 Oct 2002 16:16:11 -0500 A few years ago, we found some copper weather-stripping used on door frames in 25 foot rolls, and used that to ground our club station desk and rigs to the nearest water pipe outside the shack wall. -Stuart K5KVH ++++++++++++++++++ Message: 31 Date: Tue, 8 Oct 2002 00:06:43 -0400 (EDT) From: kc4kgu at ENTERZONE.NET To: Stuart Rohre Cc: "George, W5YR" , pjhend at ameritech.net, Elecraft at mailman.qth.net Subject: Re: [Elecraft] Ground Strap On Mon, 7 Oct 2002, Stuart Rohre wrote: > A few years ago, we found some copper weather-stripping used on door frames > in 25 foot rolls, and used that to ground our club station desk and rigs to > the nearest water pipe outside the shack wall. > -Stuart K5KVH I use 1" tinned copper braid personally. If I remember correctly, a 50ft roll of it was less than $50.00. I think I got it from CableXperts. Here is a link to the page where they sell it: http://www.cablexperts.com/cfdocs/cat.cfm?ItemGroup=7&itmsub=0&bskt=0&USA_ship=1&c=0 And I remembered correctly. 50ft of it is less than $50.00 USD. 73 de John - KC4KGU K2/100 #2490 +++++++++++++++++++++ Date: Mon, 07 Oct 2002 23:34:19 -0500 From: "George, W5YR" Organization: AT&T WorldNet Service To: kc4kgu at ENTERZONE.NET Cc: Stuart Rohre , pjhend at ameritech.net, Elecraft at mailman.qth.net Subject: Re: [Elecraft] Ground Strap Solid copper sheet is much better for r-f purposes than braid. When used indoors braid is not too bad, but outdoors the braid oxidizes quickly and develops high r-f resistance. It is fine inside the coax outer layer where it is pretty well sealed from air and moisture, but when exposed to air and humidity, it will start oxidizing and lose a lot of its effectiveness for r-f. It is mainly a skin-effect situation . . . 73/72, George Amateur Radio W5YR - the Yellow Rose of Texas +++++++++++++++++++ From: "Charles Bland" Organization: Entropy Reduction, Inc To: Elecraft at mailman.qth.net Date: Mon, 7 Oct 2002 21:34:47 -0700 Subject: Re: [Elecraft] Ground Strap Reply-To: BlandRanch at BlandRanch.net > I use 1" tinned copper braid personally. We quit using braid in RF apps because corrosion can occur and cause noise along with RF noise. This stuff is now a no-no. Chucky +++++++++++++++++ Date: Tue, 8 Oct 2002 00:46:03 -0400 (EDT) From: kc4kgu at ENTERZONE.NET To: Charles Bland Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] Ground Strap On Mon, 7 Oct 2002, Charles Bland wrote: > > I use 1" tinned copper braid personally. > > We quit using braid in RF apps because corrosion can occur and cause noise along > with RF noise. > > This stuff is now a no-no. > I thought of this. The braid that exits the QTH, all 2ft of it, is coated with protectant. It is MUCH easier to work with than solid copper, which will ALSO oxidize and suffer from corrosion if not properly protected. 73 de John - KC4KGU ++++++++++++++++++ From: "Charles Bland" Organization: Entropy Reduction, Inc To: Elecraft at mailman.qth.net Date: Mon, 7 Oct 2002 21:58:28 -0700 Subject: Re: [Elecraft] Ground Strap Reply-To: BlandRanch at BlandRanch.net I don't blame for avoiding solid copper wire. I do too, where possible. It *is* OK to use stranded copper wire. When jacketed, you have environmental protection and a good grounding conductor. I wouldn't use jacketed wire in hi moisture areas, as the jacket traps the moisture and can encourage corrosion. There may even be a code requirement for this as well, but my books aren't in the house........ I would still not use braid. Chuck > I thought of this. The braid that exits the QTH, all 2ft of it, is coated > with protectant. It is MUCH easier to work with than solid copper, which > will ALSO oxidize and suffer from corrosion if not properly protected. > > 73 de John - KC4KGU ++++++++++++++++ To: w5yr at att.net, kc4kgu at ENTERZONE.NET, Elecraft at mailman.qth.net, BlandRanch at BlandRanch.net Date: Tue, 8 Oct 2002 00:06:52 -0700 Subject: Re: [Elecraft] Ground Strap From: k6se at juno.com John, KC4KGU wrote: "I use 1" tinned copper braid personally." George, W5YR wrote: "Solid copper sheet is much better for r-f purposes than braid. When used indoors braid is not too bad, but outdoors the braid oxidizes quickly and develops high r-f resistance." ========== John said, "TINNED copper braid". The tinned copper braid that I installed at the base of my two towers over 26 years ago for grounding purposes is still shiny and shows no sign of oxidation. The 3/4" wide braid is soldered to the SO-239s on the plastic boxes which contain my 160m shunt feed capacitors and the other end is secured to a tower leg with a stainless steel hose clamp. The length of the braid is less than 6". Solid copper sheet would not suffice at all where the ground connection must be flexible, as in my case. 73, de Earl, K6SE +++++++++++++++++ From: "Sandy, W5TVW" To: "George, W5YR" , Cc: "Stuart Rohre" , , Subject: Re: [Elecraft] Ground Strap Date: Tue, 8 Oct 2002 07:40:42 -0500 I have used copper flashing for YEARS! Usually about 2-1/2 to 3" wide. There have been many times onboard ship when, even though a transmitter was bolted to a steel deck, copper strapping had to be added to "ground" the transmitter to the overhead or an adjacent bulkhead and to the deck to get things "cooled off". After the advent of computer-like devices and terminals, these seemed especially vulnerable to stray RF fields/signals! Many times a piece of flashing was routed from the radio console to the computer terminal on the insulated walls of the space, and the interconnecting cabling run down the center of this to help keep the RF out of the cabling. Not to mention used of ferrite toroid "chokes" in stubborn cases. Flashing is much more durable and weather resistant than "braid". The poorest "braid" there is, if one MUST use braid, is that salvaged from short pieces of RG-8/RG-58/RG-59 type coaxial cable. There is 1/2" and wider braid especially made for grounding, BUT it has gotten VERY expensive! Flashing can be run almost anywhere and if bends or turns are needed, it can be "folded over" on itself to negotiate, say a 90 degree turn on a wall. Out of all the things we tried over the years, it has been most satisfactory. Another item that can be used for "Grounding" and is VERY satisfactory at RF frequencies is common copper water pipe. The hard and soft varieties both, along with their associated fittings to make turns and "tees". 1/2" is an excellent size to use. Very weather resistant. At RF frequencies, it works as well as a solid copper conductor the same size would work due to the "skin effect". It IS a bit more difficult to work with however. 73, Sandy W5TVW ++++++++++++++++++