[Elecraft] K3 Sub Receiver and protecting the Sub RX input

[Lyle Johnson]

> In general, ensure the coupled energy into the receiver antenna 
> connector is less than 1 watt under absolute worst case conditions, 
> and preferably under 100 mW, and your receiver should be OK.
>
> Put another way, the antennas should be separated by 40 dB if running 
> up to 1 kW, 30 dB if running up to 100W and 20 dB if running up to 
> 10W.  You might get away with 10 dB less coupling.

Of course, I meant 10 dB *more* coupling, or 10 dB *less* isolation.

> If you can't get this level of isolation by physical separation and/or 
> orientation of the antennas, provide some external means of reducing 
> the signal to the receiver input.
>
> Yes, the K3 inputs are tested to higher levels than this, but why 
> stress the radio and risk damage to or degradation of the receiver(s)?
>
> If you hear the receiver COR relay click when using the other 
> transmitter, reduce the coupling between the antennas or otherwise 
> prevent the excess energy from reaching the receiver input.
>
> 73,
>
> Lyle KK7P
>
>> ...can you please elaborate on what is sufficient antenna separation 
>> when a transmitter is operating on another antenna?
>
>