Grounding antenna/mast/coax

[dmg1969]

I have a scanner antenna (Antennacraft ST-3) in the attic and need to move it outside because had a metal roof installed. I know this has been asked ad-nauseum, but I want to confirm my understanding of the grounding procedure.

I put a temporary test antenna outside consisting of a 10' section of PVC and used one of my old Hustler MOR-B mobile scanner antennas. The results are pretty amazing. Now I want to bring my (hopefully much better) ST-3 out of the attic and mount that outside.



My intention is to use standoff mounts on the side of our elevated deck so as to get the antenna above the roof line of the house. I would LIKE to use PVC and make a telescoping mast about 15' high. The ST-3 is not a heavy antenna. I used PVC as a mast for a weather station and it has lasted for several years, so far. IF I go the PVC route, is connecting the coax to an in-line lightning arrestor similar to this and then connecting the lightning arrestor to the grounding rod at my electrical service (which is within 8 feet of where I want to mount the antenna) sufficient? Or do I also need to run a ground from the antenna U-bolt to the electrical service ground? I know, if using a metal mast, you ground the coax AND the metal mast. And the mast is usually connected to a separate ground rod. I don't know if that would matter since the antenna would be very close the electrical service ground anyway. I'll use a metal mast if it is an exceptionally better option. It's just that PVC gives me more flexibility.

As an overabundance of caution, I plan to take the antenna down and disconnect the coax leading into the house any time there is a threat of lightning.

 

[prcguy]

What you are proposing sounds like it will meet NEC requirements. You have a nice short run to the house service panel and #10 copper wire from the lightning arrestor to the panel ground would meet code. If you install a metal mast there are additional considerations and if you install another ground rod it must be bonded to the service panel ground with no less than #6 copper wire. If a metal mast goes in your proposed location there should be no need for an additional ground rod.

 

[dmg1969]

What you are proposing sounds like it will meet NEC requirements. You have a nice short run to the house service panel and #10 copper wire from the lightning arrestor to the panel ground would meet code. If you install a metal mast there are additional considerations and if you install another ground rod it must be bonded to the service panel ground with no less than #6 copper wire. If a metal mast goes in your proposed location there should be no need for an additional ground rod.

OK. Just to clarify, if I use PVC as a mast, would I need to ground the antenna itself to the grounding rod at my electrical service or only the coax? Thanks!

 

[prcguy]

OK. Just to clarify, if I use PVC as a mast, would I need to ground the antenna itself to the grounding rod at my electrical service or only the coax? Thanks!

For a PVC pipe insulated antenna I believe a lightning arrestor in the coax line grounded to the entry panel meets code but you should check NEC article 810 to be sure.

 

[trimmerj]

Should the lightning arrestor be bonded to the mast or electrical panel ground rod? About a foot apart and bonded together with #6.
Thanks

 

[WA0CBW]

Both the lightning arrestor and a metal mast can be connected to the electrical panel ground rod if they are close together (no greater than 8 feet). If the distance is greater than that a separate ground rod should be installed at the base of the mast. This ground rod and any other ground rods MUST be bonded to the main electrical ground rod.
Bill

 

[Unidener]

Can the lightning arrestor be mounted between coax and antenna base?

 

[mmckenna]

Can the lightning arrestor be mounted between coax and antenna base?

Depends. You want the arrestor mounted where the coax enters the home. Simply placing it at the antenna base doesn't necessarily protect you as well, unless your antenna is mounted right where the coax pokes through the wall.

 

[Unidener]

Depends. You want the arrestor mounted where the coax enters the home. Simply placing it at the antenna base doesn't necessarily protect you as well, unless your antenna is mounted right where the coax pokes through the wall.

It's mounted on the deck with lattice attached to the deck surrounded by tomatoes and pepper plants and runs about 8' under the deck to the brick wall. Really should have thought of this before I dug up the lattice and unscrewed it from the deck (already put lattace back up). So the ground rod it about 4' from the deck mount so I would like to install it there so it's accessible in the event it has a problem. Not to mention the antenna will only be up when I'm using my transceiver, otherwise there will be a small scanner antenna attached.

So what I would like to do is to mount the Coaxial Lightning Arrester/Suppressor with PL-259 & SO-239 on the end of the feed line then attach it to the antenna. Will that be too close to the antenna? This also makes it easy to check my SWR before and after the connecting the arrester to the antenna.

Sound OK?

 

[Unidener]

Forgot to mention that I will be using an antenna tuner as well.

 

[W8HDU]

Personally, given the potential for mayhem with lightning, and the uselessness of most arrestors, I would run a ground down the PVC, from antenna to a ground rod, which is at the correct dept. Lightning is opportunistic. It wants the easiest path to ground and right now the outter to the coax is it, but the ground is your home and equipment. I know it costs for ground wire, but I would rather have the charge go into the earth away from the deck and house.

 

[ki6ffv]

Recommended reading for OP.

 

[W8HDU]

The "Motorola Publication R56 - Standards and Guidelines for Communication Sites" seems broke on my browser, but I'm aware of it. It's long, but excellent reading.

 

[Unidener]

The "Motorola Publication R56 - Standards and Guidelines for Communication Sites" seems broke on my browser, but I'm aware of it. It's long, but excellent reading.

Thanks! @KIGFFV & @W8HDU Very good documentation!