Re: KAT100 diodes

Posted by w9cf on Jul 10, 2011; 3:54pm
URL: http://elecraft.85.s1.nabble.com/KAT100-diodes-tp6567545p6568009.html


Thanks Don,

I do plan to evaluate the protected diodes (or better diodes if someone
suggestions them) before using them.

I do have DC paths for the antennas and an antenna switch at home, but
I've been using the K2 here in Europe while traveling with temporary
antennas and an antenna switch is an extra piece of gear that I don't
want to have to carry on the airplane. While disconnecting the antenna would
certainly have kept this from happening, I don't think a lack of a DC
path on my antenna had much to do with it since my KPA100 Rev. C has a DC
path to ground at the antenna input, and I didn't disconnect the antenna.
It's funny, but even with antennas with a DC path to ground I touch the
center conductor to ground before attaching connectors.  That's probably
from years living in Arizona where its often so dry I have to do that
even when connecting phone plugs to my stereo or TV or I'm likely
to zap something.

My hope for the KAT100 is to have a belt and suspenders approach in
the future. That is, I will try to disconnect the antenna, but if I
forget, I would like to have a circuit that can take a small amount of
discharge without destroying the diodes. Since unprotected Schottky
diodes are known to be susceptible to reverse voltage ESD damage,
I thought slightly changing the circuit might improve things while
leaving the accuracy unchanged.

Thanks again and 73,
Kevin, w9cf