Posted by
P.B. Christensen on
May 04, 2009; 8:04pm
URL: http://elecraft.85.s1.nabble.com/K3-on-channel-strong-signal-overload-tp2785612p2789121.html
> (In an extreme case, you could even be
> exceeding the useful range of the TR switch PIN diodes. The FT817, if
> I'm not mistaken, uses a TR relay.)
Some "scratch-paper" calculations in a 50-ohm system:
Assuming it really is the T/R PIN diodes, they would conduct at just under
one volt. In a 50-ohm system (and highly dependent on the PIN
configuration), that's roughly a 10 dBm signal -- or stated another way, 10
mW of power dissipated at the Rx front end.
It would be an interesting exercise to momentarily bypass the T/R PIN diodes
and re-test with the same driveway setup. So, even if this really is the
cause, it would probably be a safe assumption that the K3 will still handle
strong signals far better than most other receivers -- until an outrageously
high value begins conducting PIN diodes. That solution might call for
replacement of the solid-state T/R with a relay.
Thanks, but "no thanks."
Paul, W9AC
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