Author Topic: Lightnings and outside antennas  (Read 4509 times)

Offline Haribda

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Lightnings and outside antennas
« on: March 06, 2008, 11:03:54 AM »
I am a bit worried, I was planning to put an outside antenna (home built) on top of my building, but a friend told me it is possible for a lightning strike?

What do you recommend?



Offline Darrell

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Re: Lightnings and outside antennas
« Reply #1 on: March 06, 2008, 01:34:50 PM »
I have had my antenna on top of my house for a couple of years and we have had some severe storms here in Ohio and so far no strikes that I know of. I do have the pole and antenna grounded with a wire that goes into the ground. I am not sure if that is overkill but it makes me feel better.

Offline Biff

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Re: Lightnings and outside antennas
« Reply #2 on: March 06, 2008, 03:10:59 PM »
I live in the lightning capital of the country and have had an outdoor antenna for years as well.  You absolutely need to ground it.  I ground both the antenna, and the coax cable itself (via a grounding block). 

But yes, anything you stick up into the air has a chance of getting hit by lightning. 

Offline Lezam

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Re: Lightnings and outside antennas
« Reply #3 on: March 06, 2008, 06:39:26 PM »
I havent done this, but I think if you just run a wire from the antenna down into the ground you wouldnt have a problem. Make sure the wire ends a couple of feet from your house though

Offline phil-s

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Re: Lightnings and outside antennas
« Reply #4 on: March 07, 2008, 10:51:05 PM »
Normally I just lurk here quite happily, but ----pretty sure US NEC requires that any kind of antenna not only be grounded but that the ground rod be tied to the house ground rod (grounding electrode). Goal is to keep all grounds as close to same potential as possible, especially in the wake of a lightning strike nearby (a direct strike on the antenna or house is pretty much impossible to defend against).  Somebody who really knows this stuff please correct me if I'm wrong.   

Gecko1

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Re: Lightnings and outside antennas
« Reply #5 on: March 19, 2008, 01:18:59 PM »
Yes, it is ideal for all antennas and radio equipment to be attached to a common ground. Your house wiring does this for things with plugs, but you really should ground your antenna. If you have no access to your house's ground or a grounded cold water pipe, you will have to make your own ground. A simple wire leading into the ground won't work. You will need a copper rod, 4-8 feet (depending on the climate / ground moisture) driven into the ground, less than 9 feet from the house if possible. Then connect it to a ground block.

This protects well against static buildup in your antenna. Static is the most common cause of damage to radio systems. An actual lightning strike is much more rare. If you do happen to get a direct primary strike on your antenna, grounding can't help much, and you would be better off worrying about the grounding wire catching fire. Don't worry about direct strikes unless you live on a plain or your antenna is the tallest thing for miles, as lightning is much more likely to hit trees and power poles than an antenna.

Again, the idea of the grounding is to reduce the probability of getting hit in the first place and to continuously bleed off small static charges that can damage your equipment.