Base station grounding

[WRJQ927]

I want to set up a mobile radio as a base station with an antenna on the roof.  How would I go about grounding this? I'm having a hard time finding anything that isn't extremely technical. I could just avoid using it during bad weather, only putting it up when there is no chance of a storm, but part of the reason I want it is for emergencies - most of which in Central Texas involve storms.

I'm thinking about getting the Wouxun KG-1000G and Tram 1486  Base Antenna

Somebody must have already worked this out! 

I sent an email to BuyTwoWayRadios customer service last week. I mentioned that as soon as I get the safety info I need I'll be placing an order.  Usually, they have lightening fast response times on their customer service emails. I'm shocked I haven't heard back by now. Not sure why their customer service guys are not discharging their duties as technical helpers but maybe they have gone on strike. 

[marcspaz]

Unfortunately, grounding an antenna system is a lot more technically involved than many think.  If you don't do it correctly and ace the proper protections in the right location(s), the only thing you accomplish is increase your odds of a direct or indirect lightning strike.

 

I do EmComm for the local government as a volunteer and my home is a radio relay station.  None of my antenna systems are grounded.  If we are experiencing lightning, my antenna cables are disconnected outside the house and if I need to act as a radio relay during lightning, I switch to mobile/portable operations, which has a significantly lower risk.

 

My recommendation would be to use a professional grounding guide or one from ARRL and follow it to a T... hire a professional antenna installer and electrician to do it for you, or disconnect the coax and toss the cable on the ground until the weather passes.

[MichaelLAX]

30 minutes ago, marcspaz said:

... and my home is a radio relay station.  None of my antenna systems are grounded.  If we are experiencing lightning, my antenna cables are disconnected outside the house and if I need to act as a radio relay during lightning, I switch to mobile/portable operations, which has a significantly lower risk.

Marc: Do I understand correctly that you rely on your ability to manually disconnect your antenna system outside the house at the commencement of lightning strikes?!? 

What happens in the middle of the night?  When you are away from your home? etc...

[marcspaz]

@MichaelLAX  the weather, specifically lightning, is extremely predictable in the Mid-Atlantic. We don't get random storms and NOAA/NWS does such a good job that they are typically correct within 30 minutes as to when the weather is going to start.  Even during the peak of the season, we go weeks without rain/lightning. So it's pretty easy to disconnect when a storm is forecast. 

 

If I am going out of town, like to Florida or New England, I disconnect before I go.  I don't have any base station equipment in Florida. 

 

23 years in this house and never lost a radio or amplifier. I did lose 2 antennas to lightning strikes, but even with proper grounds and lightning suppression, the antenna is getting taken out on a hit.

[gortex2]

To do grounding the proper way will cost more than your radio and antenna combined. I would at minimum put a polyphaser/transector where the feedline enters your house. Grounded to a ground rod or building electrical if possible. Minimum should be #6. Below you can grab a polyphaser for around $75.00.

If you have a mast that is metal you should try to ground that to the same point as the polyphaser. 

https://www.dxengineering.com/search/brand/polyphaser?cm_mmc=ppc-google-_-search-_-vendors-_-keyword&gclid=Cj0KCQiAoY-PBhCNARIsABcz772B_ofhyz47cdi2i0FWZStI2MENLroGG3T5-nRA_loZkBmDokje9fsaAhwlEALw_wcB

Good manuals to look at. 

https://wiki.w9cr.net/index.php/R56_-_Standards_and_Guidelines_for_Communication_Sites

[mbrun]

I want to set up a mobile radio as a base station with an antenna on the roof.  How would I go about grounding this? I'm having a hard time finding anything that isn't extremely technical. I could just avoid using it during bad weather, only putting it up when there is no chance of a storm, but part of the reason I want it is for emergencies - most of which in Central Texas involve storms.
I'm thinking about getting the Wouxun KG-1000G and Tram 1486  Base Antenna
Somebody must have already worked this out! 
I sent an email to BuyTwoWayRadios customer service last week. I mentioned that as soon as I get the safety info I need I'll be placing an order.  Usually, they have lightening fast response times on their customer service emails. I'm shocked I haven't heard back by now. Not sure why their customer service guys are not discharging their duties as technical helpers but maybe they have gone on strike. 

As has been mentioned, the ARRL has a book on the subject of Ground and bonding. Information can be found here: http://www.arrl.org/grounding-and-bonding-for-the-amateur. If you are in the mode of learning, purchase and read it.

The ARRL also has links to a lot of other references for those that care to dig in deeper. But be aware that there are competing theories amongst true experts about the ‘Best’ way.

From a pure safety standpoint, the National Electric Code describes the minimum requirements. This means, in part, that the NEC does not concern itself with RF grounding in any way that may help or hinder radio performance. Anything you may choose to do special for RF is over and above. So, at a minimum, follow the national electric code. At least if when you do, should you have a lose from lighting, your insurance company should have no leg to stand-on in denying your claim.


Now, let’s consider a common installation and a common and appropriate method of grounding. Here is the scenario.

You have a 30 foot metal antenna mast mounted outside, next to and attached to your home. A vertical antenna is mounted to the top of the mast. Your radio will be located in a first floor room or in the basement. The coaxial cable will enter the home within a few feet of the mast.

Hear are the steps involved.

A ground rod would be driven into the ground within a couple feet of the base of the mast. A heavy copper wire (#6 AWG) or larger would be used to interconnect the mast to this ground rod. Clamps made for this purpose would be used to secure the wire at both ends.

A coax of appropriate type and length is attached to your antenna. The coax runs down and is secured to the mast periodically so it does not flail in the wind. A coaxial cable lighting arrestor gets attached directly to the ground rod. The antenna coax attaches to the appropriate port on the arrestor.

A 2nd coax connects to the remaining port on the arrestor and is runs into your home and connects to your radio. The penetration into the home is sealed well against moisture ingress.

A #6AWG copper bonding conduction is then run below ground between your new ground rod to your home’s main/primary electrical ground rod. This bonding conductor is then securely connected to both ground rods. Clamps made for exactly this purpose are used. This step ensures both ground rods are now at the same voltage potential.

If your conditions are different, then some additions to, or modifications of this basic scenario will be warranted. In the end however, the basic principles will still be applied, just perhaps in a more complex configuration.

In summary, the mast gets connected to its own dedicated ground rod(s). A ground rod exists exists within feet of where the coaxial cable enters the home. The coaxial cable from the antenna gets connected to a lighting arrestor just before it enters the home. The lighting arrestor is either attached directly to the ground rod or interconnected to it with heavy copper cable (if it cannot be conductively mounted directly to it for some reason). All ground rods are bonded together with heavy copper cable per the NEC.

And there you have it, the basics.

If you pursue knowledge on this topic you will learn that none of these precautions will prevent damage to and perhaps total loss of your equipment in the event of a direct hit. Direct hits do happen to home antennas, but are relatively rare. What is far more common is lighting strikes nearby that induce voltage on your antenna system, and the static build up on the antenna system that can shock you or damage your equipment. It is these later two more common conditions that these steps ultimately help you with.

Good luck on your project.


Michael
WRHS965
KE8PLM

[axorlov]

Michael (mburn) explained it in the detail. OP also may search this forum for "antenna grounding", since this topic is being brought up every 6 months.

[PACNWComms]

13 hours ago, gortex2 said:

https://wiki.w9cr.net/index.php/R56_-_Standards_and_Guidelines_for_Communication_Sites

I started reading this thread and went right to Motorola R56, then saw you had posted a link already. Attaching it in case that is unreachable. Chapter's 4 and 5 go into a great deal of detail on what needs to be done. Thank you for posting this. Many could take head in this before having their home catch fire or lose equipment/property/and life to a lightening strike. 

In previous work in the oil industry, ship antennas would often get hit by lightening strikes. Polyphaser's and actually grounding them in the most direct route saved all but one radio over the course of ten years. With the price of copper, it is understandable why people skimp on this part, but it could save life and property. It is an area that even the professionals try to save money. A couple of years ago, I had to have a 9-1-1 Public Safety Answering Point under construction, re-pour the concrete base of their antenna tower, as they did not place grounding mesh underneath. The building also needed some walls torn apart to retrofit grounding for the many radio racks, antenna coax penetrations, and backroom equipment. Grounding also improves signal to noise by having gear at the same effective ground, to include the call taking (telephone) systems in use at the sites. Follow R56 and do at least the minimum, adding lightening protection, copper rods and bonding pieces to each antenna/radio system.

Motorola-Standards-and-Guidelines-for-Communication-Sites-R56-Manual.pdf

[HCCFCA]

This is a timely topic as I just set up a base station and needed a lesson on grounding. All the above is VERY helpful.

I have a very basic question: How do you knock an 8 ft grounding rod into the earth? I live in an area with clay soil and many many rocks and that seems an impossible task.

[gortex2]

Well thats always a challenge. Couple of ways I do it is first drill with a 6' mason bit. Also you can rent a Hammer Drill an adapter at many home improvement stores. I own mine but they make an adapter for a ground bar. Last choice is a BFH. If using option 3 I find putting a chunk of pipe with a cap (Iron pipe) helps protect the bar. 

[HCCFCA]

Thanks for the quick reply!  I think my first action will be to stop at the local rental shop and see what they have - I hadn't thought of that option. The thought of trying to hammer a pipe  - even with a BFH -in this ground was a non-starter. That got me thinking that local electricians must have the correct tools.

Fairly new to the forum but have read many topics and have learned a lot. Thanks to the owners/moderators!

 

[mbrun]

This is a timely topic as I just set up a base station and needed a lesson on grounding. All the above is VERY helpful.
I have a very basic question: How do you knock an 8 ft grounding rod into the earth? I live in an area with clay soil and many many rocks and that seems an impossible task.

I feel your pain. Fortunately, I have been able to power through with nothing more than a small sledge.

In the past I have read up on alternative techniques that are permitted for use when a direct drive rod is not possible or electrically unsatisfactory. I just can not recall the variant’s off the top of my head.

You my wish to check out https://www.mikeholt.com. He runs an internet site many electricians turn to to learn and to work through challenges like yours.


Michael
WRHS965
KE8PLM

[AdmiralCochrane]

Took me an hour with a 3 lb hammer

[HCCFCA]

I think the only way to manually make a hole would be to use an iron pipe as suggested earlier as the copper rod would bend way before i got it a foot in the ground, that's how much stone is present. I think either rent something to drill a hole or pay an electrician to install one.

I'll have to do more research but I suppose it's not appropriate to run copper wire direct to the house ground in lieu of a ground pole near the antenna.

Thanks for the responses and suggestions. Everything else about the base installation went smoothly except this...

 

Thanks for the mike holt link BTW.

[axorlov]

2 hours ago, HCCFCA said:

This is a timely topic as I just set up a base station and needed a lesson on grounding. All the above is VERY helpful.

I have a very basic question: How do you knock an 8 ft grounding rod into the earth? I live in an area with clay soil and many many rocks and that seems an impossible task.

I use hammer drill and 4' of 1/2" rebar flattened at the end and sharpened to a spear point. After 4' hole is drilled, the rest of the rod goes much easier, with sledgehammer.

[PACNWComms]

When I was stationed at Joint Base Lewis McChord, we were issued Pionjar (gas and electric versions), Rock Breaker Hammers for pounding four foot copper ground rods (two connected to make one eight foot rod) into the ground. These devices were part of the loadout for Raytheon satellite communications terminals and troposcatter terminals. We had to put four ground rod sets in the ground, two for the terminal and two more for the antenna system. After decades of training in the same areas, we got off easy, as many units had left their rods in the ground, and we would just clip into the existing grounding rods, moving our comms terminals a few feet to get in the right position between them. These can be rented from many construction and home improvement centers.....unless you want to buy your own. https://www.amazon.com/YN27-Pionjar-Breaker-Hammer-Gasoline/dp/B01I3TKIZ6

This part of the country is in the terminal moraine of glaciers, where all the rocks and debris form at the leading edge. The glacier melts and miles of rock are strewn everywhere, making farming and pounding ground rods a huge chore. Obviously,be sure you are clear of underground cables, gas lines, and sewer pipes first. Then, use a method that works for your type of soil. Good luck, my days of pounding ground rods with hammers is gone. If it takes more than a few hits with a 15 pound sledgehammer or fence post hammer, I'll go with electric/gas tools. 

[SteveShannon]

1 hour ago, HCCFCA said:

I think the only way to manually make a hole would be to use an iron pipe as suggested earlier as the copper rod would bend way before i got it a foot in the ground, that's how much stone is present. I think either rent something to drill a hole or pay an electrician to install one.

I'll have to do more research but I suppose it's not appropriate to run copper wire direct to the house ground in lieu of a ground pole near the antenna.

Thanks for the responses and suggestions. Everything else about the base installation went smoothly except this...

 

Thanks for the mike holt link BTW.

Don’t use solid copper. Most ground rods are copper bonded over carbon steel. That’s important. Copper remains a good conductor even though oxidized.

I rented a Hilti and a ground rod driver.  The rod went in very easily even though I live on a granite mountain.  
Call 811 first for a locate if you have any doubts about buried utilities. 

[tweiss3]

3 hours ago, gortex2 said:

Well thats always a challenge. Couple of ways I do it is first drill with a 6' mason bit. Also you can rent a Hammer Drill an adapter at many home improvement stores. I own mine but they make an adapter for a ground bar. Last choice is a BFH. If using option 3 I find putting a chunk of pipe with a cap (Iron pipe) helps protect the bar. 

This. I used a hammer the first time, was too much effort. Looking to drive another one soon, so I bought a hammer drill (keep saying I need one for various projects), I'm not doing one by hand again.

[HCCFCA]

And the rest of the story...

Well...My worry about hammering in the ground rod was justified...Not! After about half an hour of hammering the ground rod, it went in as easy as I could have hoped for. Being near the house, I suspect that fill dirt was originally pushed up against the foundation when the house was built but without the rocks found on the rest of the property. So I pounded away and got it it in. If it had been a few feet away from the foundation, I would have needed a hammer drill or stick of dynamite.

Now it's wiring up the bonding wire from the mast to the rod and from the rod to the house ground by the electrical meter.

Thanks guys.

[WRPD719]

I have a mobile rig setup as base station as well.  However, I live about 200' above grade in a high rise.  I have balcony to setup my antenna's on.

I wondering what is the best way to groud my station?  I live in Chicago so the electrical code requires all electrical circuits to be in conduit and the conduit grounded to a common building ground.  So do I ground my station components to the nearst electrical box?

If not I was thinking I may have to go a more portable setup without a ground and pull my antenna off the balcony whenever I am not using it.

Curious to know if others have done in this situation.  Thanks!

[axorlov]

1 hour ago, WRPD719 said:

I live about 200' above grade in a high rise

There is no practical way to ground to the soil, but that's ok. Important is to have all your radio equipment grounded to the same ground bus. Your radio, power supply, etc will be at the same "ground" potential, which will be different from the real ground potential. But it is not a big deal. And connect this grounding bus to the building ground, to keep AC protection, as code requires.

[MichaelLAX]

4 hours ago, WRPD719 said:

I live in Chicago...

I just stopped by the authentic Portillos in Moreno Valley* Monday night and delighted to one of their dipped Italian Beef with Sweet Peppers sandwiches (and a Maxwell Street Polish)!

Just brings back so many memories...

*Riverside County, about 75 miles from my home.