[VHFcontesting] XV mods

[John D'Ausilio]

sorry about that, accidentally hit send :)

I don't know if others have had the issues I've had with the XV
transverters, but I thought I'd report on my efforts this weekend ..

I run a stack of 4 XVs driving high-power TE amps in my rover.
Antennas are short yagis spaced relatively close to each other on one
mast. I've experienced failures of the PHEMT due to the large amount
of RF present on the unselected transverters, whose configuration
leaves the gate of the PHEMT connected to the antenna connector in
that state.

I suspect bandpass filters would probably eliminate the problem (I
have one on the 6M station and it's not given me any problems), but
space is at a premium in the rover. I decided to modify the XVs in the
following fashion:

I remove the jumper from the antenna connector to the pad leading to
the common on K1, and attach it to the W3 pad that's connected to the
NO contact, then cut the trace between the NO contact and W3 (leaving
W3 and the N connector connected to the output circuitry).

I short the K1 common to ground.

K1's NC contact is conveniently already tied to the input circuitry,
and I add W2 for split output.

Cut trace to K1 coil and reroute to 12V (powered when XV selected).

This repurposes K1 to short the input circuitry to ground whenever K1
is not energized (XV not selected). It's an easy mod for 6/2/222, but
a bit of a PITA for 432 (W3 is under K1).

I've also modified my TE amps by removing the T/R relay, and am adding
external T/R after the amp.

de w1rt/john