[Milsurplus] Smart People: BC-9 TX/RX Freq Shift- Q?

[David Stinson]

Aside:
My Wattmeter was wrong.  Scope says the
radio is outputing 2 Watts.  Powerhouse!

Smart People:
BC-9 diagram again, for reference:
https://goo.gl/photos/scKooWvzUF5GwHKe6

Was discussing with a friend the problem of
the shift in  Oscillator frequency between 
the Receive freq, when the first tube is acting 
as a regenerative detector with 70V on
 the plate, and when it is keyed as a TX 
Oscillator with full 120V on the plate,
which shifts the transmit frequency lower
by about 12KC+/-.  With the B+ shifting so
much, the operation freq shifted as well.
I said this couldn't have been "normal" 
because these radios were in service 
for over a decade and it simply 
wouldn't have worked this way.

His theory had to do with my "stop-gap"
measure to get the radio working without
the full loop antenna (I have substituted
a tank coil and link-coupled output).
His position:

"Think of the math factors of the situation and
what is different.  The original loop had
a certain inductance, a certain distributed
capacitance and a certain, small series
resistance.   It is a very Hi-Q device with,
therefore, a very narrow resonance point.
You have substituted a link-coupled coil.
It has an inductance, a different distributed 
capacitance and a series resistance, 
which is much larger than that of the loop.
When you switch to Transmit, your greatly
increasing the loop currents, the IR losses 
and distributed capacitance losses, lowering
the circuit Q, flattening the resonance curve
 and thus moving the oscillation point.  The 
problem is not the B+; the problem is the
degraded Q of the circuit."

What do you think of his analysis?

73 DE Dave AB5S