LOOKING FOR INFORMED OPINION ON STATION GROUNDING PROCEDURE(S)


Phil Anderson
 


Thanks Sam, neat work for a ground, a termite ground at that!
Got my 160 mil wire now running from my cold water input pipe on the basement wall
to my radio bench. The other grounding clamp already there runs to the mains meter and rod other side of the house.
Checked with a meter at the bench, between the new safety ground wire and bare wire ground in the local 110
plug and get less than 2 ohms. Good to go.

I've got my ESD work pad and wrist gismo attached to the bench now and installing the 2nd receiver today (and tomorrow?) into
my K3........so I can run the P3 panadapter just purchased. Should be an interesting day until basketball time at 2 PM, hi, KU against TCU.

Strange things we do for ham radio!

Uncle Phil/w0xi
Friday, January 09, 2015 7:13 PM
Hello Uncle Phil,

My shack is in a converted 2 car garage - cinder block walls and concrete
floor. A minor crack appeared and those nasty little termites squeezed through
and ate some of my prize old magazines. The bug-spurt guy came and killed
then, drilling 5 holes through the concrete in the process, stopping them up
with plastic plugs/goo.

I removed two of them and with an inch to spare, I drove an 8 foot copper clad
ground wire into the ground under the slab through 2 of the holes, leaving
about 3 inches of rod showing. About as short a ground wire as I could ever
get. I then sealed the holes again, this time using hydraulic cement ( it
swells when it dries/setsw ) Keep us informed.

73,





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Sam Neal
 

Hello Uncle Phil,

My shack is in a converted 2 car garage - cinder block walls and concrete
floor. A minor crack appeared and those nasty little termites squeezed through
and ate some of my prize old magazines. The bug-spurt guy came and killed
then, drilling 5 holes through the concrete in the process, stopping them up
with plastic plugs/goo.

I removed two of them and with an inch to spare, I drove an 8 foot copper clad
ground wire into the ground under the slab through 2 of the holes, leaving
about 3 inches of rod showing. About as short a ground wire as I could ever
get. I then sealed the holes again, this time using hydraulic cement ( it
swells when it dries/setsw ) Keep us informed.

73,

Sam Neal N5AF
____________________________________________________

------ Original Message ------
Received: Thu, 08 Jan 2015 04:27:25 PM CST
From: "Phil Anderson aldenmcduffie@sunflower.com [4sqrp]"
<4sqrp@yahoogroups.com>
To: "4sqrp@yahoogroups.com" <4sqrp@yahoogroups.com>
Subject: [4sqrp] LOOKING FOR INFORMED OPINION ON STATION GROUNDING
PROCEDURE(S)

Hey guys,

Getting ready to sheet rock my shack in the basement - to keep it warmer
- and pondering how best to provide a safety ground, i.e. electrical
ground. Of course, want to wire the ground before adding the rock, hi.

I am assuming the right way is to run a separate (but costly) large
copper wire, 160 mil diameter from the earth ground connection at the
main electrical box or secondary box (have one of those too) to my
station location. Dr. Murphy (of Murphy's Law) of course saw to it that
my station is at the other end of the house! Hi.

Then, I noticed that there is a 160 mil (big copper) wire running along
a 2x4 header in the basement ceiling to the intake of my water line half
way of the basement wall, secured with a ground clamp (which ACE
hardware sells too). Hm. Perhaps I could run that remaining ten feet to
my bench? I measured the resistance from the bare wire ground on a
basement outlet to the water pipe and it is about 3 ohms. So for sure
the cold water pipe is connected to my main box ground, likely directly.

However ("There is always an however," Mr Murphy says) the national
electrical code - via a google search says DO NOT use a cold water pipe
connection for the earth ground in a three prong socket replacement for
a two prong socket (1950 era slang). I remember those.

Hm? Unc Phil in cold Lawrence, KS/W0XI


Don Wilhelm <w3fpr@...>
 

Dr. Don,

I disagree that any ground rod and connection to it via any wire or copper strap will be an effective RF Ground.

I think of 3 things that are considered "ground" - the first is AC safety ground (follow the NEC rules for compliance), and the next is Lightning Protection Ground, which is more complex than the AC ground - one can find good information on that subject on the Polyphaser website.  Ron Block had a 3 part series in QST some time back and I consider that a good resource.

Then comes "RF GROUND" - that is a nefarious term and is very often misunderstood.
No "ground wire" will provide an RF Ground if there is any length of wire or copper strap required to connect to Mother Earth.  Consider a good driven ground rod system outside the shack, then connect it to the shack with an 8 foot long wire or copper strap.
Now -- remember that RF flowing on a wire follows the same rules as for antennas and transmission lines - the impedance is low at the ground point, but is high 1/4 wavelength from that point.
On 10 meters, that 8 foot wire is about 1/4 wavelength long - so it has a low impedance at the connection with the ground rod, but at the end of that 1/4 wavelength wire, the impedance is quite high -- hardly a good ground for RF.

My view is that RF Ground is more of a concept than any physical thing.  It exists at the point(s) where the RF voltage is zero.  That occurs midway between the transmission line connection to a dipole, and midway between the transmission line connections to a vertical monopole and the ground plane.  It also occurs at several other places in the antenna field and transmission line system.  Creating an RF Ground in the hamshack at all frequencies we operate is an insurmountable task.

The solution is to keep the RF from getting back into the shack.  That is what baluns and current mode chokes on the transmission line are for.  Jim Brown K9YC has an excellent tutorial on handling RFI in the hamshack - see http://www.audiosystemsgroup.com/RFI-Ham.pdf -- his common mode chokes are good (he does not like the term 'balun') and quite effective.

In other words, keep the RF out of the shack and there is no need for an "RF Ground" in the shack - in fact, it is impossible to construct an RF ground in the shack at all frequencies.

73,
Don W3FPR    

On 1/8/2015 6:01 PM, Don Sanders w4bws1@... [4sqrp] wrote:
 
Unc Phil, I believe the reference to not using the cold water pipe as ground is when there is no other ground provided. In your case I believe the cold water pipe is "using" the main AC ground just as you proposed. You would be using the same main AC Ground as the water pipe if you ran the 10 foot wire from the water pipe to your station AC ground. 
However this would not be a good RF ground. For a good RF Ground you should use a separate ground rod and wire( actually a 1 inch wide flat copper strip is best)  from the station. And then possibly a couple radials run either around your basement ceiling or external to the house. Depending on the bands needed, one for 40, 30, and 20 meters. 
Here I use a flattened 1 inch diam aluminum pipe from the station to three 6 foot ground rods spaced 5 feet in a triangle and bonded together with heavy welding cable. I added a 1/4 wave wire on 80 meters as a counterpoise to reduce the RF in the shack, lousy rocky/sandysoil, and use an MFJ artificial ground tuner. No RF in shack now. The equipment 3rd wire ground does go to the main AC input ground. 
Possibly others will have other good advice from their experiences. So far in 60+ years, no equipment damage from lightening, but I did have a couple tower hits which burned thru the coax wrapped around the tower leg, bonded to the tower and its ground.




Robert 'RC' Conley <rc.kc5wa@...>
 

On Thu, Jan 8, 2015 at 5:01 PM, Don Sanders w4bws1@... [4sqrp] <4sqrp@...> wrote:
 

Unc Phil, I believe the reference to not using the cold water pipe as ground is when there is no other ground provided. In your case I believe the cold water pipe is "using" the main AC ground just as you proposed. You would be using the same main AC Ground as the water pipe if you ran the 10 foot wire from the water pipe to your station AC ground. 
However this would not be a good RF ground. For a good RF Ground you should use a separate ground rod and wire( actually a 1 inch wide flat copper strip is best)  from the station. And then possibly a couple radials run either around your basement ceiling or external to the house. Depending on the bands needed, one for 40, 30, and 20 meters. 
Here I use a flattened 1 inch diam aluminum pipe from the station to three 6 foot ground rods spaced 5 feet in a triangle and bonded together with heavy welding cable. I added a 1/4 wave wire on 80 meters as a counterpoise to reduce the RF in the shack, lousy rocky/sandysoil, and use an MFJ artificial ground tuner. No RF in shack now. The equipment 3rd wire ground does go to the main AC input ground. 
Possibly others will have other good advice from their experiences. So far in 60+ years, no equipment damage from lightening, but I did have a couple tower hits which burned thru the coax wrapped around the tower leg, bonded to the tower and its ground.


Dr. Don HC4/W4BWS









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--
another day in paradise CQ CQ CQ


Donald Sanders
 

Unc Phil, I believe the reference to not using the cold water pipe as ground is when there is no other ground provided. In your case I believe the cold water pipe is "using" the main AC ground just as you proposed. You would be using the same main AC Ground as the water pipe if you ran the 10 foot wire from the water pipe to your station AC ground. 
However this would not be a good RF ground. For a good RF Ground you should use a separate ground rod and wire( actually a 1 inch wide flat copper strip is best)  from the station. And then possibly a couple radials run either around your basement ceiling or external to the house. Depending on the bands needed, one for 40, 30, and 20 meters. 
Here I use a flattened 1 inch diam aluminum pipe from the station to three 6 foot ground rods spaced 5 feet in a triangle and bonded together with heavy welding cable. I added a 1/4 wave wire on 80 meters as a counterpoise to reduce the RF in the shack, lousy rocky/sandysoil, and use an MFJ artificial ground tuner. No RF in shack now. The equipment 3rd wire ground does go to the main AC input ground. 
Possibly others will have other good advice from their experiences. So far in 60+ years, no equipment damage from lightening, but I did have a couple tower hits which burned thru the coax wrapped around the tower leg, bonded to the tower and its ground.


Dr. Don HC4/W4BWS









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Don Wilhelm <w3fpr@...>
 

Phil,

First you should physically verify that the wire is indeed connected to the utility ground wire outside.� If it is, then you can use it to connect your shack ground.� The utility ground wire should connect to its own driven ground rod located as close to the electrical entry box as possible.

I think you are misinterpreting that NEC prohibition against using a cold water pipe as a ground.� There were times in the past when a cold water pipe was used as the *only* ground point in a house.
If that heavy wire connects between your cold water pipe *and* the utility entry ground rod, then you are OK, but if that cold water pipe connection is the *only* ground connection for the utility ground, then that is not a good thing and should be corrected.

If you cannot easily determine that you have an existing ground rod at your utility entrance, you could "play it safe" and drive a new ground rod at the utility entry point and connect the existing ground wire to that new rod.� If you want to comply with new grounding rules, drive another ground rod 6 feet away from the first and connect the 2 ground rods together with #4 wire (#6 qualifies as sufficient, but #4 is better).� The ground wire and the ground rods can be buried, in fact most inspectors prefer that they be buried because there is then a smaller chance that the ground wire could be cut with a lawn mower or weed cutting device.

If you are looking to that ground connection for lightning protection from your antennas, then that 160 mil wire is not adequate for the job (it is adequate for AC safety ground).� For lightning protection, run 2 or 3 inch wide copper strap to the outside ground rod and do not use any sharp bends - lightning likes to travel in a straight line.

An even better protection for lightning is to run a perimeter wire around your house (#6 or larger wire) with a driven ground rod at each point where the wire makes greater than a 45 degree turn - it only needs to be 6 inches to a foot deep.� That perimeter wire should also connect to the Utility Ground Rod (all ground rods must be interconnected for safety).� That perimeter wire will help keep a lightning surge traveling through the earth from punching a hole in your foundation.

73,
Don W3FPR

On 1/8/2015 5:27 PM, Phil Anderson aldenmcduffie@... [4sqrp] wrote:
�

Hey guys,

Getting ready to sheet rock my shack in the basement - to keep it warmer - and pondering how best to provide a safety ground, i.e. electrical ground. Of course, want to wire the ground before adding the rock, hi.

I am assuming the right way is to run a separate (but costly) large copper wire, 160 mil diameter from the earth ground connection at the main electrical box or secondary box (have one of those too) to my station location. Dr. Murphy (of Murphy's Law) of course saw to it that my station is at the other end of the house! Hi.

Then, I noticed that there is a 160 mil (big copper) wire running along a 2x4 header in the basement ceiling to the intake of my water line half way of the basement wall, secured with a ground clamp (which ACE hardware sells too). Hm. Perhaps I could run that remaining ten feet to my bench? I measured the resistance from the bare wire ground on a basement outlet to the water pipe and it is about 3 ohms. So for sure the cold water pipe is connected to my main box ground, likely directly.

However ("There is always an however," Mr Murphy says) the national electrical code - via a google search says DO NOT use a cold water pipe connection for the earth ground in a three prong socket replacement for a two prong socket (1950 era slang). I remember those.

Hm? Unc Phil in cold Lawrence, KS/W0XI



Phil Anderson
 

Hey guys,

Getting ready to sheet rock my shack in the basement - to keep it warmer - and pondering how best to provide a safety ground, i.e. electrical ground. Of course, want to wire the ground before adding the rock, hi.

I am assuming the right way is to run a separate (but costly) large copper wire, 160 mil diameter from the earth ground connection at the main electrical box or secondary box (have one of those too) to my station location. Dr. Murphy (of Murphy's Law) of course saw to it that my station is at the other end of the house! Hi.

Then, I noticed that there is a 160 mil (big copper) wire running along a 2x4 header in the basement ceiling to the intake of my water line half way of the basement wall, secured with a ground clamp (which ACE hardware sells too). Hm. Perhaps I could run that remaining ten feet to my bench? I measured the resistance from the bare wire ground on a basement outlet to the water pipe and it is about 3 ohms. So for sure the cold water pipe is connected to my main box ground, likely directly.

However ("There is always an however," Mr Murphy says) the national electrical code - via a google search says DO NOT use a cold water pipe connection for the earth ground in a three prong socket replacement for a two prong socket (1950 era slang). I remember those.

Hm? Unc Phil in cold Lawrence, KS/W0XI







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