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Date: Thu, 23 Sep 2010 19:50:55 +0200
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From: "Roelof Bakker" <roelof@ndb.demon.nl>
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Subject: Re: LF: PA0RDT miniwhip in TX?
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Hello Mike,

> My antenna was mounted 15' off the ground with a ground wire connected  
> to the coax braid right under the antenna.

That is interesting. This might imply that the ground at the antenna is at  
the voltage level induced in the 15' long wire to ground. This might lead  
to a number of unforeseen effects. So, I wonder if the FET was damaged due  
to induced voltage on the PCB antenna or due to the voltage over the wire  
to ground.

I have mounted the antenna at about the same height, but the shield of the  
feedline is connected to a ground stake at the bottom of the mast. I use a  
BNC panel mount feedthrough like this one:

http://rocky.digikey.com/weblib/Emerson/Johnson/Web%20Photos/CP-AD-556M.jpg

It is mounted on a small piece of aluminium sheet, which is connected with  
a short wire to the ground stake.
The feedline is broken up at the bottom of the mast and two BNC connectors  
have been fitted.

Though real heavy thunderstorms are rare in this part of the country, I  
have had strikes within 300 m with no ill effects on the antenna.

73,
Roelof, pa0rdt