Hi Chuck:
One of the problems with many of the swr protection circuits is that when
there is a direct short the measured reflected power may be zero - simply
because there is no voltage present because of the short.
I learned that the hard way when someone put a new piece of coax on our club
station without testing (it was shorted). He turned the rig on and there
was no output. So he turned the rig on full power, key down and went
outside to see if he could see anything. After 20 minutes, he turned the
rig off and told me. The finals were blown, and I was elected to replace
them The rig used standard swr foldback circuitry - which does not work if
there is a short.
Colin K7FM
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