[Elecraft] How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

[Mark Wheeler]

Don,

Thank you.
Mark

On Jan 01, 2019, at 10:14 AM, Don Wilhelm <donwilh at embarqmail.com> wrote:

Mark,

The assumption that "there is a way to use both radios at the same time" 
is the real base of the problem.

A lot depends on the power level you are running - the problem get worse 
as the power is increased.

If you can reduce the pickup on the antenna used by the non-transmitting 
radio, that will help a lot. A horizontal antenna on one and a vertical 
on the other radio may be sufficient at lower powers. Physical 
separation between the antennas will help as well, as well as good 
common mode chokes on the feedline - use one at each end of the feedline 
to choke off RF that is picked up on the non-transmit feedline.

If you do not have to listen to the non-transmit radio(s) during 
transmitting, the problem becomes one of only protecting the other 
radio(s) front end. There are devices to accomplish that, or you could 
simplify things by adding a relay that is activated to short the input 
of the non-transmit radio when transmitting by the other radio. That 
relay (or relays) can be activated by the transmitting radio's amp 
keying output.

As you can imagine, this can get complicated with only 2 radios, but you 
also mentioned the inclusion of SDRplay, which may mean more than 2 
receivers, and the situation becomes even more complex.

73,
Don W3FPR

On 1/1/2019 7:34 AM, Mark Wheeler via Elecraft wrote:

I see lots shack photos with two transceiver setups, especially two
Elecraft K3S radios; how do you isolate the 2nd transceiver or SDR
receiver (SDR Play, for example) so that you do not damage one
transceiver while transmitting with the other?  I am assuming there is a
way to use both radios at the same time.

Can I safely use an antenna switch to switch between multiple
transceivers using one antenna, or will I risk damaging the
non-transmitting radio on the other side of the antenna switch?