Industry Forums > Wireless Service Providers > How to ground radios and sectors

How to ground radios and sectors

you need to run the ground wire in teh trench back to the shack as well. ALL grounds MUST be at the same potential. and the antennas should be grounded individually. or run something like #2 up the pole and #4 from each antenna to it.
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Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!

reply to pacmanfan
Do you know if these antennas are DC-grounded?

I'd put a copper buss bar at the top where the antennas are, and use #2 solid to bond the antenna mounts to the bar, and then run solid #2 down the pole to the driven rod (8-foot long, buried 24" below grade). This joint to the rod needs to be exothermic welded to ensure 100% mechanical and electrical contact. I'd also weld on a tap to run to the shack and bond the equipment to that bond (use another buss bar for multiple connections). Depending on how far away the shack is, you might want to add another ground rod at the shack that is bonded to the running tap from the pole ground. If you do this, run the buss bar for the shack down to this rod. Like david says, ultimately you need to have everything bonded together.

Also between the radio and the antenna you should put a lightning protector on the coax jumper right before it enters the radio. Ground this arrestor to the buss bar as well.
--
"No job is so important, and no service is so urgent that we cannot take the time to do it safely."
-- AT&T
--Safety One Tower Rescue Certified
--LLigetfa:"Wimax is like teenage sex. Everyone talks about doing it."

reply to pacmanfan
To add to what has been written here already, if it's an extended run from the pole to the shack consider adding additional ground rods along the run. I'm not sure what the soil is like up your way but down here it's sandy so we drive 20'-30' 5/8" or 3/4" ground rounds to hit the water table. The rods should be spaced 2x the length of the rod, so with 8' rods you'd drive one every 16'. #4 minimum, we have standardized on 1/0 and have bought several different molds, but I don't think I'd use less than #2 or equivalent. Like stated above be sure to bond everything together! DAMHIK

reply to pacmanfan
Nice point Rhaas. Another option to driven rods are the chemically enhanced rods or CU plates.

I'm a huge fan of the chem rods now. If I'm not afforded the opportunity to put in a huge ring, I'll spec out a chem rod if the budget allows as one chem rod can be better than multiple standard rods, as the soil is enhanced with bentonite clay, and the rod to earth contact is further enhanced with special salts that leach out of the rod.
--
"No job is so important, and no service is so urgent that we cannot take the time to do it safely."
-- AT&T
--Safety One Tower Rescue Certified
--LLigetfa:"Wimax is like teenage sex. Everyone talks about doing it."

reply to pacmanfan
We have had a bad year... In the past five years we have had one tower (the same one) hit three times by lightening. Finally we figured out that there was a faulty ground on that tower... NO MORE LOSSES.

Now, along comes August 2008 and we have 9 towers hit in one week. NINE towers in one week. Not a single radio killed, but we had Canopy radios on every tower and they need GPS sync from their CMM. GPS sync is delivered over the same pairs that PoE is delivered.

We discovered that surge supression needs to be at the TOP and at the BOTTOM of the tower, even if it is properly grounded.

We put three 10' ground rods at the base of every pop. We connect them in a halo. Then we put surge supression at BOTH ends of any POE that is on the tower.

You should too.

reply to pacmanfan
Can we use same cable in every sector + lan protector?

reply to AnonGroundedDOG

reply to AnonGroundedDOG
AnnonDog how are you grounding things at the top of the tower?

reply to lutful

said by lutful:

I concocted an example to separate the usual bonding/grounding arguments from surge protection. Let's imagine a fighter plane refuels in mid-air and also transmits some data over the hose. It is obvious that we will need robust surge protection at both ends of the hose to prevent fireworks.

reply to AMD Phreak
We run a wire up the pole when it is a free standing pole, just like the phone company and power company do.

When it is a tower, the tower is ground.

We put surge supression at the top and bottom of every run of cable now and ground the surge supressor.

Sd i hope you dont mean dielectric grease.... dielectric is an insulation grease. You must mean No-al-ox?

And putting the ground straps across the joints is a good idea on the tower if you plan on using it for a ground. I had a discussion with Splitpair about this very subject last week and he also indicated that this would be a good idea if one were insisting on using the tower for ground. You just cant trust the joints for a real ground. Lightning would be shunted yes but static charges no..... and bleeding of the static is what this is all about.

EDIT:

Now that I am on a real KB and not a PDA lol....

I've started to move to doing the tower top grounding the correct way: Bar at the top bonded to the TGS via exotherm welds. The downconductor is solid #2 sleeved in PVC conduit (sched 40) to protect it from incinental contact and to eliminate RF interference possiblilites. All arrestors and coax ground kits if applicable are bonded to this bar.

It is imporant to note that this design only works if you have a fully-functional ground system. This means you have a TGS (tower ground) and a shelter ground. Both must be bonded together for this to work otherwise you might as well not do anything at all.

reply to AMD Phreak

reply to superdog

Special clamps are made by Harger for this. When I get into the office I'll share what I use.

EDIT:

Here are the clamps. There are various sizes.

»www.harger.com/products/grdcmp/m···/cpc.cfm

What I do is using a wire brush on a drill, clean up the area on the tower where the joints will be made. Coat liberally with Penetrox A, and make the joint. I also coat the part of the clamp where the CU wire is held, with Penetrox to just ensure that the joint does not oxidize. After the joints are made, I hose everything down a few times with zinc-enriched paint, from Rustoleum. I make sure I spray down plenty to get it to run down in and around the joint. I figure between the Penetrox and the zinc paint it wont rust.

reply to superdog

said by superdog:

I am not sure that copper can be welded to steel?. What would the best method be to attach the strap other than welding?.

reply to AMD Phreak
BTW run stranded between them to allow for the difference in expansion and contraction of the tower and the jumper. While very slight it will be a problem with solid.

Wayne
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If you cannot fix it with a buttset and some beanies you ain't a technician.