Lightning Arrestors
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| Jun 2nd 2012, 13:48 | |
KapAceHighTotal Topics: 0 Total Posts: 0 |
When I was WB2MHI from 1963 to 1968, the only type of coax lightning arrestor was the gap type, which I installed on my coax transmission line right ouside the entrance to the shack. after about 42 years, I'm again a licensed ham,KC2ZDT, but still have vintage vacuum tube gear. My question is this: is a gas discharge tube type arrestor necessary with vintage tube equipment. Thanks, Bob K KC2ZDT |
| Jun 5th 2012, 18:55 | |
WA0CBWTotal Topics: 0 Total Posts: 0 |
Bob, Tube type equipment may offer a little more protection against lightning damage through the antenna than today's solid state equipment. The purpose of the coax cable lightning arrestor is to attenuate the surge voltage that comes down the coax because of a nearby lightning strike. Most lightning damage is usually caused by flash over between things that are at different ground potentials. It is probably more important to connect all of your equipment to a single point ground. Along with the phone, internet, cable tv and any other wires that come in or out of your house. Bill ARRL Technical Coordinator - Kansas Section |
| Jun 6th 2012, 22:28 | |
KapAceHighTotal Topics: 0 Total Posts: 0 |
Bill, Thanks for the information and the importance of grounding everything. Guess the best precaution is to disconnect the antenna and power from all the equipment ahead any approaching thunderstorm. Bob KC2ZDT |
| Jun 7th 2012, 15:39 | |
WA0CBWTotal Topics: 0 Total Posts: 0 |
Bob, Yes, grounding is your friend. But don't be be fooled by thinking that that after lightning has traveled several miles through the atmosphere that it will be stopped by the two feet of distance between the coax connector and something in your shack that is at ground potential. Bill |
| Jul 25th 2012, 15:27 | |
WA0CBWTotal Topics: 0 Total Posts: 0 |
John, Good lightning protection begins with the principle of "single point" grounding. That is all grounds go to a single copper bus located near the entrance of all coax cables. The buss should be at least 1/4 inch thick and sized length/width to accommodate all the ground wires. This bus should connect to your outside ground and the electrical panel ground. Connected to this bus would be all your equipment and all your surge protectors. Each device should be a "home run" from the device to the ground bus. In addition it would be a good idea to connect the cold water pipe to this same bus along with any telephone, cable vision, or satellite cable ground. The idea is during a voltage surge you want EVERY piece of equipment to rise with the voltage. If one piece of equipment is at a different potential then the chance of an arc-over can occur. Most lightning damage occurs because of arcing between pieces of equipment or wiring or piping. Bill |
| Sep 26th 2012, 02:44 | |
JMWinPRTotal Topics: 0 Total Posts: 0 |
I would recommend PolyPhasers on the coax, and use coax grounding straps at each right angle bend, and at the entrance to the shack. I would also disconnect everything when storms approach and connect the antenna feeds to a "cantenna" or equivalent. This will help to keep it from bouncing around the shack. Don't count on objects 150 yds away to take the hit. After you've been hit a couple of times, it sort of comes natural. |
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