Grounding antenna?

[jnojr]

I'm planning on putting up a Diamond X50 on a 10' mast attached to the gable of a 2 story house (different than my "stealth antenna" question!) I'm looking into grounding, and am hearing everything from "Bah, don't bother!" to "YOU ABSOLUTELY MUST HAVE AN ELABORATE GROUNDING SYSTEM OR YOU AND ALL YOU LOVE WILL DIE!!!1!!1"

This antenna will not be near the electric panel. There is a cold water pipe on the same wall... I figure I could run a ground wire to it. Is that going to be sufficient?

There will be a lightning arrestor in the coax, and it needs to be grounded as well, so... same place?

 

[mmckenna]

The people that tell you "Bah, don't bother!" are people you should avoid. Those that confuse luck with skill usually run short of both sooner or later.

You really should read the pertinent parts of the National Electric Code. Following NEC will keep you right with your local jurisdiction, and in a worse case, your homeowners insurance.

https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf

Ultimately you should consult with an electrician that is trained in this sort of stuff. Hobby websites are not an authoritative source of information. But the above PDF will give you the general idea of what the NEC requires.

Looks like water pipe can be used as a ground conductor, but you'd want to:
1. Double check with a professional.
2. Make sure that it is actually copper/metal pipe all the way through.
3. That it is actually bonded to your ground rod.

The protector/"Antenna Discharge Unit" could be bonded to the water pipe, but again, double check.

 

[CanesFan95]

I find reading the NEC difficult and confusing. You can't even get to it without having to create a password, and then it doesn't let you actually download and save it. The terminology is too hard to understand.

But I have a very similar setup but used a 5' mast instead, to reduce the wind load. I hired an electrical company to install a 2nd ground rod directly under the gable and run a #6 copper wire underground from the 2nd ground rod around to the original ground rod (this is called "bonding"). Then a lightning arrestor in the feedline with #6 going straight down to the 2nd ground rod.

 

[kingshootr]

I'm planning on putting up a Diamond X50 on a 10' mast attached to the gable of a 2 story house (different than my "stealth antenna" question!) I'm looking into grounding, and am hearing everything from "Bah, don't bother!" to "YOU ABSOLUTELY MUST HAVE AN ELABORATE GROUNDING SYSTEM OR YOU AND ALL YOU LOVE WILL DIE!!!1!!1"

This antenna will not be near the electric panel. There is a cold water pipe on the same wall... I figure I could run a ground wire to it. Is that going to be sufficient?

There will be a lightning arrestor in the coax, and it needs to be grounded as well, so... same place?

Being a fellow Arizonan, and recently jumping into scanning, I learned that most if not all houses here for the past several decades, grounded houses not with stakes driven into the ground, but a method called "UFER". This is a link to a thread I did a bit ago, in case there is any info that might help.

Another "How to Ground" Thread...

 

[trimmerj]

Replaced siding and fascia on house and looking to remount several masts. Do i need a seperate ground for each mast or can I bond them together and run a single ground lead to the ground rod?
thanks

 

[mmckenna]

Ideally you want a separate ground running straight down from the mast to ground.
Not always an option, though, especially in residential/hobby installs.

I'd run the ground leads down to the ground and to a common point, then one ground rod. Remember to bond any new ground rods to the existing home ground.

 

[trimmerj]

Ideally you want a separate ground running straight down from the mast to ground.
Not always an option, though, especially in residential/hobby installs.

I'd run the ground leads down to the ground and to a common point, then one ground rod. Remember to bond any new ground rods to the existing home ground.

Thanks

 

[Radiomatrix]

Hi—-it’s grounding time again!
My antenna, A99 is on a 20 foot galvanized pole.
I have some stranded 4ga copper ground wire and an 8’ 5/8” copper grounding rod.

The rod will go in very near the base of the pole with the grounding wire running straight up to the antenna bracket.

THEN WHAT?

Would I simply use a band clamp to attach the wire to the pole?

would it be ok to spray paint the copper wire?

the coax runs down the pole and into PVC that is routed underground to the house where it goes through the wall and into the garage to the bench where the radio is.

the radio does not have a 3-prong power cord.

comments please.

 

[prcguy]

Hi—-it’s grounding time again!
My antenna, A99 is on a 20 foot galvanized pole.
I have some stranded 4ga copper ground wire and an 8’ 5/8” copper grounding rod.

The rod will go in very near the base of the pole with the grounding wire running straight up to the antenna bracket.

THEN WHAT?

Would I simply use a band clamp to attach the wire to the pole?

would it be ok to spray paint the copper wire?

the coax runs down the pole and into PVC that is routed underground to the house where it goes through the wall and into the garage to the bench where the radio is.

the radio does not have a 3-prong power cord.

comments please.

Not the best way to ground an antenna and using a separate ground rod puts the antenna and associated radio equipment at a different ground potential than your house ground exposing you to more damage during a lightning strike. The National Electrical Code says any additional ground rods you put in must be bonded to the house main ground with no less than 6ga copper wire. Its legal to ground your antenna with a short run of 10ga copper wire to your house main ground. If the run exceeds about 30ft its best to upsize the wire.

 

[paulears]

I love these topics. So much of what you MUST do has little to do with radio, but everything to do with local codes, rules, and codes of practice from the electricity supply perspective. I guess the other thing of course is your weather.
we don’t have US extreme weather in the U.K. and nobody, almost, takes lightning precautions. Domestic and TV dishes, antennas and support systems are rarely grounded. A few pull out cables when storms are around because we do get lightning, but it’s rarely ever a problem. We do, however, have very taken seriously rules about grounding in homes and businesses. The idea is to create equi-potential zones, to ensure people do not touch surfaces at different potentials, so things like outside buildings, sheds, garden sockets have very strict grounding requirements. The problem of course is that radio users like to have their own grounds for noise reduction. This breaks the rules on bonding. Oddly, it means that all U.K. TV antennas and dishes are grounded through the coax screen, that‘s it! A commercial tower will be bonded to ground, and the ground system of the buildings close to. Coax coming down the tower usually has ionising devices fitted. Homes do not have to do this. Mine certainly doesn’t. My antennas ground via the coax. We here rarely run a separate ground wire up to them. In my own case, my repeater case is connected to mains power ground through the IEC cable, that is it. I’m not aware of any lightning issues being reported by the ham/hobby community. People do get hit, but house insurance covers that kind of thing.

 

[Radiomatrix]

Not the best way to ground an antenna and using a separate ground rod puts the antenna and associated radio equipment at a different ground potential than your house ground exposing you to more damage during a lightning strike. The National Electrical Code says any additional ground rods you put in must be bonded to the house main ground with no less than 6ga copper wire. Its legal to ground your antenna with a short run of 10ga copper wire to your house main ground. If the run exceeds about 30ft its best to upsize the wire.

https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf

This link points to an antenna discharge unit, probably not necessary if I can somehow connect the grounding rod to the house ground (Plumbing pipe/faucet?).

i think i am understanding more how it must be connected to the house ground.

what about the antenna setup? Ground rod and 4ga stranded copper up the pole
attached with a band clamp near the antenna?

Then I run a 4-6ga solid copper wire to the something connected to the house to tie everything together.

I think I am understanding this right.

 

[Radiomatrix]

If i under stand this right, i just need to tie the antenna ground to the house ground?

my options are a run to the telephone NIC box or the nearest plumbing fixture-the hose bib. The actual house ground is on opposite side of house where power enters the house.

 

[paulears]

Ignoring the rules/code/good practice discussion, I've never been absolutely firm about why we ground? The comments from companies always seems to be that grounded metalic structures up high, do not 'attract' lightning strikes, but simply discharge charge already in the vicinity? certainly you can plonk a sensitive meter on your antenna and see voltage - often surprisingly high.

So an ungrounded antenna is more or less likely to 'attract' a strike, or not? I tend to think that if you get hit, then th path between antenna and ground should keep that high current spike away from the inside of your house. If you get hit and you only have the coax, then it goes inside. I've heard lots of anecdotal opinion that this wrecks the room, but even if you ground the antenna, I can't believe some of the current won't get in - after all, you need something with substantial cross section to carry huge currents down to ground - usabel and affordable copper that can carry hundreds of amps means at best you might be OK, but I bet lots of 'grounding' wire melts, leaving your coax to carry the load?

No gripe here, but so much conflicting advice and bendy physics? Buildings, even high ones here don't need lightning conductors, it's just suggested as nice to have.

 

[Radiomatrix]

Ignoring the rules/code/good practice discussion, I've never been absolutely firm about why we ground? The comments from companies always seems to be that grounded metalic structures up high, do not 'attract' lightning strikes, but simply discharge charge already in the vicinity? certainly you can plonk a sensitive meter on your antenna and see voltage - often surprisingly high.

So an ungrounded antenna is more or less likely to 'attract' a strike, or not? I tend to think that if you get hit, then th path between antenna and ground should keep that high current spike away from the inside of your house. If you get hit and you only have the coax, then it goes inside. I've heard lots of anecdotal opinion that this wrecks the room, but even if you ground the antenna, I can't believe some of the current won't get in - after all, you need something with substantial cross section to carry huge currents down to ground - usabel and affordable copper that can carry hundreds of amps means at best you might be OK, but I bet lots of 'grounding' wire melts, leaving your coax to carry the load?

No gripe here, but so much conflicting advice and bendy physics? Buildings, even high ones here don't need lightning conductors, it's just suggested as nice to have.

yes i agree. Grounding the antenna reduces the electrical potential and the chance of a strike….i guess.

I have agonized over this for a ling time reading the different takes on the why to ground but it is makes more sense little by little because even though it is described in electrical terms the same concepts come through. For example your comment about discharging the electrical potential already in the vicinity Is a common message i see.

So right now, home depot delivers a 25 foot section of 4ga stranded wire today. I cannot get an answer about how to attach the wire to the antenna. So when that is done, the coax, from the grounded antenna enters my house to the radio that is plugged in with a non grounded two prong plug.

The PDF link talks about NEC code for this application and what i think i get from this is the recurring message that it has to be bonded somehow to the House ground.

All this is thought to protect against a lightening strike, but what I think my understanding is that it is reducing the electrical attractivity of my antenna to reduce the chance of a strike while reducing noise.

 

[Radiomatrix]

The house gas meter pipe , i just discovered, is at the corner on the other side of the wall from my radio. Can I connect the grounding rod to this pipe via #4 or #6 solid copper wire buried.

 

[prcguy]

If i under stand this right, i just need to tie the antenna ground to the house ground?

my options are a run to the telephone NIC box or the nearest plumbing fixture-the hose bib. The actual house ground is on opposite side of house where power enters the house.
View attachment 148220

Yes, NEC calls for grounding to the main house ground to the AC entry panel. In your case where the main ground rod is on the other side of the house its probably best to install a new ground rod but that must be bonded back to the main ground rod at the AC entry panel. 45yrs ago I had the same problem as you and installed a ground rod at the base of my antenna on the opposite side of the house with no other bonding. Turns out that ground rod was much closer to my neighbors AC entry panel and ground rod which was apparently fed from another feed from the pole. That created about 90VAC between my antenna and coax shield vs my own house ground and I would get serious shock connecting or disconnecting my antenna to the radio connected to my own house ground.

I later learned during a lightning strike much of the damage to electronics in the house is from a huge difference in potential between equipment on the ground conductors and when everything is at the same ground potential going back to one single point ground its much safer. So if you install another ground rod it should be bonded to the main ground on the other side of the house and if the run is very long like more than 30-40ft you should upsize the wire from 6ga to maybe 4ga or larger and that gets expensive.

 

[mmckenna]

The house gas meter pipe , i just discovered, is at the corner on the other side of the wall from my radio. Can I connect the grounding rod to this pipe via #4 or #6 solid copper wire buried.

No. The gas pipe is not a grounding electrode, and not a suitable place to ground your antenna. Often the gas pipes transition to a plastic pipe under ground. You may find that the metallic gas pipe is bonded somewhere, but that's for equalization of potential.

As for wether to ground or not, I have to think about all the CB'ers and scanner hobbyists that never ground their equipment, yet somehow survive. No, it's not to code. No, it's not right. But somehow they survive.

There is a risk by skipping grounding. Probably not high, but absolutely not zero.

Generally, NEC is about safety. If you look at the NEC regarding grounding of antennas, it's very minimal. If you go look at the Harris or Motorola site grounding documents, it is quite extreme, but has been proven to work.

 

[paulears]

Connecting something thatcould be carrying hundreds of amps and can melt metal, to a GAS supply pipe, rather makes you think Hi, my name is John, and I'm going to be your undertaker? I suppose of pushed, my view would have to be if you are a professional, then do what other prod do - and commercial installs are always bonded. Yet we put cell antennas on a local 200 ft grain silo - and on the very top is a ham repeater, with a very tall antenna, on the highest part, and that is grounded to the building metalwork, because grain is a huge fire risk. The repeater was moved from the top of the one block of flats that has even better take-off, but the local council wanted the hams to guarantee it would not attract lighning or catch fire. They said they could not guarantee that, and got de-sited, hence the move.

 

[Radiomatrix]

No. The gas pipe is not a grounding electrode, and not a suitable place to ground your antenna. Often the gas pipes transition to a plastic pipe under ground. You may find that the metallic gas pipe is bonded somewhere, but that's for equalization of potential.

As for wether to ground or not, I have to think about all the CB'ers and scanner hobbyists that never ground their equipment, yet somehow survive. No, it's not to code. No, it's not right. But somehow they survive.

There is a risk by skipping grounding. Probably not high, but absolutely not zero.

Generally, NEC is about safety. If you look at the NEC regarding grounding of antennas, it's very minimal. If you go look at the Harris or Motorola site grounding documents, it is quite extreme, but has been proven to work.

I know I am going to ground my setup, you have been around since my very first post here on this forum, you may have been my first respondent…BTW, i got my radio back from the shop….long story.

from the grounding rod, i am running the stranded 4ga up the length of my antenna pole…what say you?

 

[mmckenna]

I know I am going to ground my setup, you have been around since my very first post here on this forum, you may have been my first respondent…BTW, i got my radio back from the shop….long story.

from the grounding rod, i am running the stranded 4ga up the length of my antenna pole…what say you?

If the support mast is metal, you only need to ground the base, no need to run the #4 all the way up to the top.

In a commercial installation, the coax would be bonded to the tower/mast at the top and at the bottom. You'd also have the lightning protection device where the coax enters the home, and that would be grounded.