Motorola has an excellent article on grounding at telecom sites...a bit high end for amateur residential settings but worthwhile readings nonetheless...Google Motorola R56 standard and give it a read
In my ears of telecommunication some broadcasting, there have been different methods. Broadcasters go with a 4in wide copper scrap to interconnect everything. Telecommunications uses 4 gauge or larger wire in a halo ring inside then a single conductor outside to a buried halo system consisting of several 8 foot ground rods tied together using cathodic welding. Nothing can prevent a direct strike, you can only mitigate the damage. The only real way to prevent damage is unplug every cable to the equipment before lightning occurs Chris WB5ITT On Wed, Apr 8, 2020, 6:16 AM Mark Brantana via BVARC <[email protected]> wrote: > Since folks are hunkered down anyways, here is a problem. I am improving > my emergency radio capability by adding a 2-m radio to my home office. Who > knows where this thing is going, and I think this is a good time to > prepare. I would like your thoughts or experience with the following. > > > > I am looking to mount a 2-m antenna on my roof. Currently I have a TV > antenna attached with a j-pole just below the chimney output. I have a > single-story house. My plan has been to extend the j-pole about 4 ft > higher to get better TV reception, and mount the antenna just above it. I > do have to watch out for offending the HOA. > > > > My property has power lines running parallel with the back of the house, > and these power lines are about 35 feet high and 35 feet laterally away > from the chimney. > > > > I am concerned about a couple of things: > > 1. Some day I may want to start a fire in the fireplace, and I do not > want the heat to get to the antennas. This is why I have the TV antenna > mounted below the top of the chimney. > 2. I would like to avoid arching or lightning strikes, though I think > it is quite common for most of us to have power lines around to contend > with. Two thoughts here: > 1. Of course, I will ground it all. > 2. I wonder if the power lines might protect the lower antennas > since lightning may hit them first. I mention this since the first > thought > was that the power lines might add to the lightning risk, not detract. > 3. That said, lightning does what it wants, and even a nearby > lightning strike, as opposed to a direct strike, will do significant > damage. > > > > On that last point, I will share a short story. When in Louisiana many > years ago, we got into a discussion about how lightning had destroyed a lot > of equipment in a member’s shack. This included, as I recall, about 3-5 > computers, and about as many radios. This was all sitting on a metal > table. Due to the lightning storm, the Ham had disconnected all of the > antennas. Lightning hit his tower and made the 2” jump to the table. The > rest was history. But, that was not the story I wanted to tell. That was > the discussion we were having. Another Ham broke in and told us that he > had a tower at one end of his house which was operational, and he had just > that day mounted a short marine antenna at the other end of the house on > his chimney. It was a dark and stormy night the previous evening, and the > lightning passed the tower to hit the yet unconnected marine antenna. So, > lightning does not follow the rules. > > > > OK, so I diverged. I really would like to know what experience and advice > you can offer me on my project. The power lines make me nervous, and I > really wish my best mounting option were not in the heat zone of the > chimney. > > > > Mark > > N5PRD > > > > > > > > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >
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