Folks,
For those who have a need for something to add CW PTT to the K2, I have my
prototype circuit working. This should serve the needs of those who must
delay keying until a transverter sequencer will allow RF as well as those
who drive amplifiers with slow relays and already use software, a footswitch
or other means of changing to transmit mode. I really don't need this
myself, but I have been curious to see if I could make a hardware
implementation work. Wayne has said he would like to do this in firmware
(for a more 'elegant' solution), but has neither the memory space nor the
time to do it anytime soon.
I have not cut any PC board traces for this mod, but it will not meet
Elecraft standards because it needs wires to bring the proper signals to a
small piece of perfboard. The only change to the K2 circuitry is that R1
and R2 on the RF board are removed to open the normal path for the paddle
lines.
The parts needed are a 74AC153PC integrated circuit, a 2N7000, and 5 - 2.2k
resistors - also a piece of perfboard to wire the circuit onto, a jack for
the new PTT input, a single wire plug/jack assembly to disconnect a wire
that must go to the SSB board and some double sided foam tape to mount the
perfboard onto the left side panel - use your own ideas for the PTT input
jack placement.
I will take some photos and get something up on my website soon so you can
see how I made the connections. I am posting at this premature time so
those who are anxious to put this in their K2 will have advance oportunity
to gather the parts (Mouser has everything needed except the circuit board -
get that at Radio Shack - it only needs to hold a 16 pin DIP and the
resistors).
73,
Don W3FPR
Life is what happens when you are making other plans
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