When you close the key, 5V is applied to unbalance the ring. A pot with a switch can take the place of that. Wiper of the pot thru the switch then to TP13 thru a diode and probably a 2k resistor. One side of the pot to ground, the other to 5V. Put the uB in CW and turn the pot to the desired output. I know it works, I did it on my Bitx 40.
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On 01/20/2021 04:12 AM, Evan Hand wrote:
I have not tried to use a variable voltage on the mixer diodes to
control power through the unbalanced ring. Not sure if that would work,
though would be curious as to the theory on how it would work.
You still need to adjust the CLOCK#2 signal of the Si5351 and turn off
the other two CLOCKs.
To do as you are suggesting, you could install a switch between the
CW-KEY and R104 to connect R104 to the CW-KEY or to a variable resistor
to adjust the voltage that is connected between the CW-KEY and R104.
Throw the switch and then press the CW key/PTT to get a lower level tune
signal. Switch it back to do the normal operation. It would require
that the CW mode be straight key, not keyer and that the CW mode is set
in the v6 (not required in prior versions, just need the CW key connected).
Above are speculations, so I could be off.