[Elecraft] K3 Main/Sub audio routing

[Dick Green WC1M]

If I'm reading the K3 manual correctly, there are limitations on how audio
from the Main and Sub receiver can be routed to the headphones. The way I
read it, if Sub is off, audio from the Main receiver will appear in both the
left and right headphones. If Sub is on, audio from the Main receiver will
appear in the left headphone and audio from the Sub will appear in the right
headphone. Is this correct, and are these the only audio routing options?
If so, is this something that can be changed in the firmware, or is it a
hardware limitation?

 

I ask because there are two alternative audio configurations that are highly
desirable, at least for me:

 

1. If Sub receiver audio can be routed to *both* headphones, I can utilize a
second RX-only antenna. I can connect the first RX-only antenna to RX ANT
and listen to it with the Main receiver. I can also connect a second RX-only
antenna to ANT 2 or AUX RF, route that antenna to the Sub receiver, route
Sub audio to *both* headphones, turn off the Main receiver volume, and
listen to the second RX antenna only on the Sub receiver. This configuration
takes advantage of having two identical receivers.

 

2. When chasing split DX, I like to put the DX station's audio both
headphones and the pileup in only one headphone (usually the right, if the
pileup is "up".) That way, it's easier to hear the DX station when it comes
back to a caller.

 

It looks like I might be able to select alternative #1 by doing the
following:

 

1. Set CONFIG:SPKRS to 1 (force mono)

2. Set CONFIG:SPKRS+PH (enable simultaneous speakers and headphones)

 

However, the manual is not clear on two points. First, it says that
CONFIG:SPKRS=1 disables the right channel. Is that true, or does it mix the
left and right channels together so Sub audio can be heard through a mono
speaker? Second, it's not clear whether CONFIG:SPKRS+PH only enables
external speakers or also enables the internal speaker. If so, I guess a
plug could be inserted in the external speaker jack to disable the internal
speaker. This is not as simple and intuitive as flexible audio routing, but
it's better than not being able to utilize a second RX antenna.

 

Note that both alternative configurations can be selected on the Orion,
which allows audio from either receiver to be routed to either or both
headphones. It isn't practical for alternative #1 because the Orion Sub
receiver is quite inferior to the Main receiver. But it can be used for
alternative #2.

 

73, Dick WC1M