[Milsurplus] BC-9 Loop Test: Scratching My Head.

[Hubert Miller]

The Q whether high or low isn't a dynamic figure while the tube characteristics are. 	
Q is just not responsible for what you are seeing. 
We assume that all radios had to have netting ability. Maybe that was not the case with this radio. 
You could still use it to communicate. Like the example of the early Forest Service 33 MHz radios
that transmitted and received on differing frequency. 
Miller effect appears at the grid. Don't ignore the larger change in capacitance and impedance
at the plate of the tube. 
As i suggested, you may want to try increasing the plate feedback ratio capacitor, C1-lower.
That will be a palliative, not a cure, though. 
Or, assuming you really want on-frequency operation, you could operate the set with the same
B+ on transmit and receive, say something like 90 volts max, maybe. Yes, your power out will
go down to 1/3 or 1/4, but you'll still be able to make demonstration QSOs. 
-H