[Collins] rit for kwm-2a

[Dr. Gerald N. Johnson]

On Thu, 2008-08-07 at 17:20 -0400, yash at aol.com wrote:
> Would like to add a RIT to my kwm-2a. I know that John Web ,now sk. 
> used to have a kit for sale. Any chance any one has one sitting around 
> the they would sell? If there are any articles about adding a RIT to 
> the kwm-2a ,I haven't been able to find them anywhere.If anyone knows of 
> the article ,please point me in the right direction.
> thanks
> dale wt4t

There is something of an RIT in the PTO already, used to shift the PTO
by the difference between the BFO crystals, so it stays on the same
carrier frequency when shifting from LSB to USB. That could be driven by
a variable voltage, or a similar circuit involving the variable
capacitor and diode (used as a variable resistor) hooked to the cathode
of the oscillator tube as was once used for FSK and RTTY could be used.
I'm describing the CR301, C308, R303 (R30 in my schematic) circuit.
Alternatively a variable capacitance diode (varicap) could tap on that
cathode. Needs to be switched to a mid position for transmit to make it
RIT.

Dig deep back into late 50s, early 60s QST for the RIT, I think.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer