[ARC5] ARC-5 VFO question

[Mike Hanz]

Neil Barnett wrote:

>In the ARC-5 transmitter, why is the return side
>of the 1626 heater connected to the (cathode) tap
>on the oscillator tank coil?
>This q. has puzzled me for 35 years, and I never
>have seen a satisfactory answer.
>

The following is an integration of slightly different wording in the 
ARC-5 T.O. and original ATA manual, the latter frequently having 
somewhat greater technical insight into design issues.

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


73,
Mike KC4TOS