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Gas Discharge Lightning Protector Units ?
Hello:
Thinking of getting (finally) one of the gas discharge tube lighning "protectors: for my receiving only long wire antenna. Radio is grounded (hopefully) via a solid strap to the water pipes and also via the ac power center-pin grounding pin. a. They seem to come in two flavors. One with an extra lug for running another ground wire, and those that don't; the argument being, I guess, that the metal case connects to the chassis (e.g., via a short piece of coax), and thus shunts any voltage transients that way. Any opinions on whether the lug with a separate ground wire is a good idea and really needed ? b. Alpha Delta units still pretty much the state of the art, or... ? c. They usually quote a number like 60 V for the gas discharge tripping. Wouldn't this usually be more than enough to fry the front end ? Thanks, bob |
Gas Discharge Lightning Protector Units ?
Single point earth ground is THE most critical component of
a lightning protection 'system'. Yes it is a system - not just one silly component called a protector. If that protector does not discuss the 'system', then the protector is suspect. Do you think for one minute that the radio chassis ground is sufficient for protection? The you did not even learn principles taught in primary school concerning Ben Franklin. Does a protector stop, block, or absorb the transient? Only in your dreams. Effective protectors perform same as Franklin demonstrated in 1752. You don't stop, block, or absorb what three miles of sky could not. And yet that is the snake oil that some protector manufacturers sell to those in denial of their primary school science lessons. Protector is nothing more than a temporary connection from that lightning struck antenna to earth ground. Sometimes that connection can be made with a wire. But if a direct hardwire connection cannot be made (ie to AC electric or telephone), then we use a protector to do the same thing. Furthermore distance to earth is critical. The connection through protector must be less than 10 feet. That means the antenna lead must first drop to earth so that a protector can make the less than 10 foot connection to earth ground. Also water pipes have long been unacceptable grounding. The only wire connected to water pipes is a wire that removes electricity from those pipes. This being post 1990 code. Furthermore, grounding to water pipes would be more than 10 feet to earth ground - totally unacceptable. In the other post is a concept essential to lightning protection - the single point earth ground. It is demonstrated by this industry professional where each structure - the building and the tower - have their own single point earth grounds: http://www.erico.com/public/library/...es/tncr002.pdf From http://lists.contesting.com/_towerta...il/004413.html The basic scenario is to install a Single Point Ground System that is installed at the building entry. It shunts everything to ground before it goes in the building. If you can keep it outside, then you don't really have to do much inside. IMO disconnecting the cables is more psychological than preventive. Yes, early 20th Century hams would disconnect the antenna, put that antenna lead inside a mason jar, and still suffer damage. Again the idea that one would stop or block the direct lightning strike was proven wrong - as demonstrated by others who even suffered explosive damage as a result. Once that antenna lead was earthed, then lightning damage stopped. Success because they shunted (connected, diverted) lightning to earth (what it seeks) rather than silly mythical solutions that try to stop or absorb a transient. The most critical component in a lightning protection system is not the protector. The protection 'system' is only as effective as its most critical component - single point earth ground. Robert11 wrote: Thinking of getting (finally) one of the gas discharge tube lighning "protectors: for my receiving only long wire antenna. Radio is grounded (hopefully) via a solid strap to the water pipes and also via the ac power center-pin grounding pin. a. They seem to come in two flavors. One with an extra lug for running another ground wire, and those that don't; the argument being, I guess, that the metal case connects to the chassis (e.g., via a short piece of coax), and thus shunts any voltage transients that way. Any opinions on whether the lug with a separate ground wire is a good idea and really needed ? b. Alpha Delta units still pretty much the state of the art, or... ? c. They usually quote a number like 60 V for the gas discharge tripping. Wouldn't this usually be more than enough to fry the front end ? Thanks, bob |
Gas Discharge Lightning Protector Units ?
On Wed, 14 Dec 2005 14:27:22 -0500, w_tom wrote:
I'm really glad I live where there's virtually no lightning. |
Gas Discharge Lightning Protector Units ?
Robert 11,
"IF" you have a Long Wire Antenna that is located OutSide then you should look at those things that can be done OutSide to improve your Antenna System from the effects of a nearby Lightning Strike to your Antenna, Radio Equipment and possibly your House. 1. An OutSide Remotely Located Ground far away form the House. 2. With a LongWire Antenna use a Matching Transformer (UnUn) between the Wire Antenna Element and Ground; and the Coax Cable Feed-in-Line. 3. Use a Coax Cable Feed-in-Line and bury it if possible. 4. Use an Antenna Switch between the Antenna's and the Radios in the Shack. The type that lets you dixconnect the Antenna from the Radios and Short the Antenna to Ground for Safety. Note - Many of these Antenna Switches have GDT's built into them. http://www.universal-radio.com/catalog/switch/2415.html 5. When you are not using your Radio and Antenna disconnect the Coax Cable from the Matching Transformer outside the House. "IF" you have a Long Wire Antenna that is located InSide your House or Attic. 1.A Ensure that your House and Wiring meets the Standards for your Area for Lightning Protection. 1.B. Improve your Shack Grounding and Electrical Sysyem Bonding as best as you can. 2. With a LongWire Antenna use a Matching Transformer (UnUn) between the Wire Antenna Element and Ground; and the Coax Cable Feed-in-Line. 3. Use a Coax Cable Feed-in-Line between the Wire Antenna Element and the Radio. 4. Use an Antenna Switch between the Antenna's and the Radios in the Shack. The type that lets you dixconnect the Antenna from the Radios and Short the Antenna to Ground for Safety. Note - Many of these Antenna Switches have GDT's built into them. http://www.universal-radio.com/catalog/switch/2415.html 5. When you are not using your Radio and Antenna disconnect the Coax Cable from the Matching Transformer outside the House. hope this helps - iane ~ RHF |
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