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Old May 16th 04, 12:26 AM
Eric F. Richards
 
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John Barnard wrote:

Is there much one can do for sensitive electronics? For example, during the
summer at my QTH, late day thunderstorms are common and on one such day I
did have the antenna disconnected from my Drake R-8B but a FET still managed
to get fried and I needed to send the radio back to Drake for repair.


First off, it could have been damaged by a surge and failed later.

Second off, with reputable lightning supressors such as Polyphasers,
properly set up, the radio is actually safer than it is when
disconnected because the supressor will crowbar (dead-short)
nanoseconds after the strike starts, when the threshold voltage is
reached. It remains shorted as long as current is flowing.

It should be noted that a simple static discharge such as touching a
doorknob and getting a spark has to be about 3000 volts before a
visible spark occurs. That is way above the crowbar voltage of the
Polyphasers.

Regards

John Barnard

"Eric F. Richards" wrote:

Volker Tonn wrote:
But for sure you can not do it by yourself and it will cost a LOT. And
at least there is NO insurance it will work under ALL circumstances.
Best (additional) way to go is to disconnect the antenna when leaving
the shack or lightning is coming up whilst you are in your shack.


Not true. You have to be anal-retentive as hell to make sure that it
is done right, but you can do it properly using the right equipment.
Polyphaser or I.C.E. protectors do the job well, but they must be
mounted on an appropriate ground window. The object of the game is
not to have your equipment at ground potential; rather the object is
to have the potential on all the equipment rise and fall together so
there is no differential amongst the equipment.

There is quite a bit of introductory material at www.polyphaser.com.

Eric

--
Eric F. Richards,
"Nature abhors a vacuum tube." -- J. R. Pierce, Bell Labs, c. 1940


--
Eric F. Richards

"The weird part is that I can feel productive even when I'm doomed."
- Dilbert
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