An alternative to a relay (which should ground the sub-receiver ant)
is using a pin diode to short the input.
Typically one uses a coupling capacitor to isolate the antenna from
the circuit which will have a low value of dc bias to turn on the pin
diode which will conduct to ground and short the antenna ckt. I
assume the K3 sub-receiver antenna ckt is capacitively coupled to
isolate it dc wise. Use a RF choke between pin diode and antenna to
keep from loading the antenna in normal use. hint: google pin diode
antenna switching.
Use KEY OUT ckt from the K3 to control the pin diode via a transistor
switch that applies the bias thru a dropping resistor. You will have
to do some design work - not plug-n-play freebie
Many ham rigs that do QSK use pin-diode TR switching.
73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[email protected]
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