[Elecraft] K3 Receiver Protection

[Don Wilhelm]

Jeff,

That is a logic question seeking an answer.  I don't know of a simple 
solution, but it is a matter of selecting a match of the outputs of 2 
band data decoders.  If any two are the same, assert TX INH to both K3s.

That function could be implemented with a number of NAND gates or XOR 
gates at the outputs of the 2 band decoders.  The exact implementation 
of the logic gates is "left to the student", there are several 
possibilities, but it would take a number of external logic gates to 
implement.

If you are really into logical devices, you could program a chip to do 
that directly from the band data outputs - if all 4 of the outputs from 
both K3s are a match, assert TX INH to both transceivers.

I do not know of an existing device that will provide that function, so 
the implementation would have to be created 'from scratch'.  Yes, it is 
possible, it is just a matter of "a few logic gates".

73,
Don W3FPR

On 6/1/2014 12:04 AM, Jeff via Elecraft wrote:
> My station consists of two K-3's, each with a dedicated legal limit amplifier and SteppIr antenna. To minimize interference between bands I am using Array Solutions Bandpass filters. However, if both rigs accidentally wind up on the same band I run the risk of overloading the front end of the opposite rig and damaging the receiver (which I've done once...). Does anyone have a way of taking the band data information and disabling transmit capability on both rigs if they are on the same band? How are others using SO2R avoiding same band transmission and subsequent receiver damage? Anyone have any experience with the Array Solutions AS-RXFEP front end protector?
>