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Lighting Protection

Jan 13th 2012, 01:01

Jartoc

Joined: Nov 19th 2011, 03:00
Total Topics: 0
Total Posts: 0
I am new to the Ham world, just receiving my license in November. I opted to get a Kenwood mobile radio to use also as a base to be versatile. With that, I also purchased a Comet vehicle antenna to serve both the vehicle and base needs. The thing that I cannot understand is how to protect the equipment with a ligthing surpressor. I certainly know why it is needed, but in terms of installing one in my configuration I cannot find much information. Do I need one, where best should it be placed, and what would be a good surpressor are all things that I could use help on.
Jan 13th 2012, 06:47

KE8DO

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Can you give more details? What band are you using, HF, VHF or UHF? How is your antenna mounted for base station use? The bigger and higher that your antenna is, the more inportant a good ground system and lighting surpression is. In your case, it may be just easier to disconnect the radio when it is not in use. For your best signal, it would be better for you to also have a base station antenna.
73 Don KE8DO
Jan 13th 2012, 23:52

Jartoc

Joined: Nov 19th 2011, 03:00
Total Topics: 0
Total Posts: 0
It would help if I provide some information on the equipment, my apologies!

The antenna is a Comet CSB-750A, and is for 2M/440MHz. I have it mounted on the side of my upper roof. Reception and transmission has been good.
Jan 15th 2012, 04:29

WA0CBW

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
The basics of good lightning protection consist of using a single point ground and surge arrestors on the coax, telco, AC, and TV cables entering your house. A simple installation might consist of a ground rod at the coax cable entrance. The coax surge arrestor would be connected to this ground. A ground wire from the radio would also be connected to the same ground. This ground should also be bonded to your AC entrance panel ground along with any grounds connected to your telco and cable TV grounds. The purpose is to create a "single" point where all grounds are connected together. When there is a nearby lightning event and the induced surge voltage rises to tens of thousands of volts you want everything in your shack to rise together. Most lightning damage is caused by flash-over from one piece of equipment or structure that is ground and something that is of a different potential. The surge arrestors job is to try and clamp the voltage rise to some safe value (usually giving up their life in the process". Don't forget to ground the surge arrestors (if they have an external ground point) to your single point ground. Your ground wires should be no smaller than #10 and preferably #6.

A very good grounding reference is Motorola's R-56 Standards and Guidelines for Communications Sites. Polyphaser also has some good grounding information. And don't forget the ARRL publications on grounding your station.

Don't forget that in a direct lightning strike nothing will save your equipment but the steps you take may help to prevent you from becoming a direct hit.

Bill - WA0CBW
ARRL Technical Coordinator - Kansas Section

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