[Milsurplus] BC-9: Answer One Question, Get Another.

[David Stinson]

The mystery of the frequency shift appears to be
solved:
https://goo.gl/photos/Cp3hyLwEJmX3Ua3M7

But that brings-up another question:
Just how does this freq. compensation work?
The manual is available as a PDF at:
https://drive.google.com/file/d/0B1zXYo8XYQS8MmgtNHVsektvT1k/view?usp=sharing

A simplified schematic is on page 19 (PDF paging).
A full diagram is on page 20 (PDF paging).

It appears that the compensation cap, C6,
when the rig is keyed, is connected one
side to the Cathode circuit of the RF stage
and the other, in series with the .001 cap
in the Plate circuit filter, to the center of
the Oscillator tank at the junction of
the C1 caps.   So the effect is in
the cathode circuit?  Anyone understand
what's going on here?

73 Dave AB5S