[Collins] Collins Xmitter Split Frequency Control

[Dr. Gerald N. Johnson]

On Wed, 2006-02-15 at 15:51 -0800, Ian wrote:
> This is a link to the schematic I jotted down 30 years ago when I "solved"
> my split frequency problem with the 32S-1 and 75S-3 working together.
> 
> I had a bit less drive than I had without using the switch but plenty for
> good reception and to get plenty of output from the 32S-1 even driving my
> 30S-1.
> 
> I added a wafer on the back end of the switch on the 32S-1.
> 
> http://home.comcast.net/~postedpics/32S1/32S-1-Split-Mods.jpg
> 
> 
> 
> Ian, K6SDE

Yes with your switch connections you should get lower drive, but that's
because the 110 terminating resistor is switched wrong. It should be
connected to the oscillator not used in transmit. You have it hooked so
it loads the transmitter oscillator when the mixer is also loading it.

That resistor should be connected to the transmit cable in the second
from left connection and to the receiver oscillator when connected to
the right two positions. Just about the opposite of your connections.
Then the gains should be consistent no matter the switch position,
providing the crystals have equal activity in transmitter and receiver
and the tubes are up to snuff in both.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer