[Elecraft] RX Ant Preamps and the K3 12v Accessory Jack

[Geoffrey Mackenzie-Kennedy]

If you are planning to use closely spaced Tx and Rx antennas, I would 
suggest that you consider using a Reed relay or similar "fast acting" relay 
to short circuit the external preamp's input during transmit periods. 
Without it there is some risk that during transmit periods the external Rx 
preamp's input device could be damaged, even if the preamp's DC supply is 
turned off while transmitting.

Of course if diodes are used for protection instead of a relay, the diodes 
could generate Tx harmonics which are then radiated by the Rx antenna.

73,

Geoff
GM4ESD

David Cutter write on Saturday, August 21, 2010 at 8:07 AM:

> I'm thinking this might also act as a gate to prevent excessive rf getting
> into the K3 2nd rx.  I'm planning to have a horizontal receive antenna
> located adjacent to my vertical transmit antenna for diversity reception. 
> I
> was just investigating the ICE196, but this idea might be better.