[Elecraft] K3 transmit/amplifier relay

[Don Wilhelm]

  Guy,

Don't forget that KEY OUT is driven directly by the 7R signal in the K3 
- that signal reaches and controls all the circuits that are turned on 
for receive.
So it cannot be accomplished entirely in firmware without an 
accompanying hardware change.

Any internal hardware change would require a firmware change - I don't 
think there are explicit signals in the K3 at the moment to create the 
necessary gating, although they may be combined with other functions in 
the firmware.

73,
Don W3FPR

On 3/13/2011 4:12 PM, Guy Olinger K2AV wrote:
> I am not so sure that this cannot be accomplished in firmware.
>
> And I completely get what this causes if one has a complex pre-K3 setup
> switching tower-top preamps, etc., whose primary state-change signal comes
> from
>
> Only the CPU knows that VOX is on or off.  There is no "VOX lead".  "Band
> down" and "VOX" share the same physical switch using "tap" and "hold".  The
> paddle states are interpreted in the CPU, there is no separate physical
> keyer circuitry.  Follow the /DASH or /DOT leads in the schematic and you
> will see it goes straight to the CPU.  Also there is no physical monitor
> oscillator which is keyed by 7T.
>
> This gives me the firm gut estimate that firmware CAN clean this up.
>