[ARC5] "Curing Chirp in Command Transmitters" MO T-53A and B

[AKLDGUY .]

Hmmm.
I refer to my copy of the manual, Section IV, Theory of Operation, under
the heading:
4-40. Radio Transmitters T-18/ARC-5, T-19/ARC-5, T-20/ARC-5, T-21/ARC-5,
and T-22/ARC-5.

4-42. Master Oscillator Circuit.
This paragraph describes various components and then says:

"...T-53B is a twin winding on the master-oscillator coil, wound from
ground to the cathode tap
in order to maintain the heater at the same r-f potential as the cathode,
so that variations of
cathode-to-heater capacitance within the tube will not affect the frequency
of oscillation."

The word bifilar is not used, although "bifilar" could be inferred from
"twin". I must admit I didn't
think about the significance of twin, thinking it meant that winding T-53B
was inter-wound with
winding T53-A as far up as its tap.

I've looked quickly through the entire manual and can find nowhere where
your usage of the
word "bifilar" is mentioned. If you can point me to where the manual uses
it, I'll check.

I was correct that the purpose of connecting heater pin 7 to cathode was to
minimize the effects
of heater-cathode capacitance changes, since it says so in the quoted
passage above.

I will not be replying for several hours as it's now 5.22pm and I need to
get ready to go out for
dinner.

73 de Neil ZL1ANM