Lightning Protection A5C

I am installing new A5C and was wondering if it would be a good idea to use in-line coax lightning protection between the N5-360 antenna and the A5C? These are cheap enough and if they would help avoid AP loss in the event of lightning strike, that would be worth the few extra dollars they cost.

Just was wondering if there would be any performance issues by using these:

We have never used them, I think the benefit would be if you are using really long runs for your cabling to your radios. Otherwise if it’s only a couple feet then a lightning strike that close wont be blocked by a set of these.

Most antennas will come with their own grounding anyways so their usefulness might only be on long runs that themselves get hit with lightning.

If you decide to use these then I would highly recommend testing to make certain they do not effect performance in any way.

Yes, you are correct. The antenna being so close to the AP itself, if it took a direct lightning hit I agree it would not make a difference. As you stated, these are probably used where there is several foot between the antenna and the AP. Back in the old days we took so many lightning hits with our equipment I guess I’m just trying to think of anything that could avoid having to replace equipment every year.

Excellent grounding is our key, we don’t have nearly as bad of storms as other places, nor do we have them as frequently, but they are bad enough and we have pretty unreliable power for where we are in the United States and I have not had a single AP go bad on us on one of our towers in the four years I have been working here and reportedly we have not lost a radio in over 6 years since we implemented our (seemingly fanatical) grounding system on towers.

If it has a grounding lug we ground it to a grounding bar that we run 6 GA (or larger for our taller towers) wire from the grounding field to. Some stuff doesn’t have grounding lugs and we will sometimes figure out ways of grounding it even so. We also run shielded wire to all of our devices and ground the shielding as well. We also annually check our grounding fields to make certain that there are not any bad or damaged connections as well as check to make certain they are still operational.

Hi Kent2 (+ Wm5),

All good suggestions here, and the A5c does have a chasis ground terminal.

As William5 mentioned- Inline polyphasers and gas discharge units on long (lmr-400 type) coax runs might provide extra protection. There is very small insertion loss @ 5GHz.

So my application will be installing an A5C on a metal mast on the top of a 4th floor building. Should I run a #10 copper ground wire from the grounding lug on the back of the A5C to the bottom floor and ground with a copper grounding rod in the ground? Or do I ground the A5C to the metal mast pole, and then ground the mast and run to ground?

@Kent2, I would setup a copper bus bar at the top and ground the antenna, A5c and the mast to it (Or ya, know, just attach the grounding bar to the mast.)

I am not certain of the math, but at least for our ground we frequently have to use +2 grounding rods to get decent ground. Then again, we are borderline dessert dry and our dirt is terrible, so YMMV. Unfortunately our grounding guy is really busy lately and I won’t have a chance to chat with him before I forget about it.

His biggest reference material and something I have seen other people refer to as well is Motorola’s R56 Manual section 4 where it talks about grounding equipment.