[Milsurplus] BC-9: A Big Road Block

[David Stinson]

By using an external tank coil in place of the loop and 
link-coupling, I'm getting good, sensitive receive and
am able to get a good Watt of power
out on 80 Meter CW.  
https://goo.gl/photos/SthdKR1rmwxXkZ6z6

I had this dream of making a few contacts 
with it during Novice Rig Roundup.  
But now there's a big problem I should have 
seen coming.  Take a look again at the diagram:
https://goo.gl/photos/THcWRvYScQfnp5gg9

The RF stage is regenerative through the plate
resistor, R5.  This reduces the plate voltage on
the RF tube during receive from 120 VDC to
70 VDC.   To transmit, the plate resistor is shorted,
the full 120 VDC is applied resulting in a strong
oscillation for transmitting.  
And here's the rub:  What happens with a non-
crystal tube oscillator when one raises the B+
from 70V to 120V?  Right- the transmit freq
jumps higher by several KC.
Some movement is to be expected, but I suspect
that the original VT-1 didn't move as much as
the substitute 6AQ5; otherwise the rig wouldn't
have stayed in service for a decade.

Irreversable changes are absolutely forbidden.
Not sure how I'm going to address this.  Always
feel frustrated if I don't get at least one QSO out
of a rig.   Perhaps something can be done in
the substitute tube mounting.  I'm open 
to suggestions?

TNX OM ES 73 DE Dave AB5S