[Milsurplus] Smart People: BC-669 Xtal Subber to Class C

[David Stinson]

Still working on the TX Xtal subber for the BC-669.
Moved away from the Class A WA1FFL circuit.
Decided to take advantage of that 0 to 6 Volt 
square wave from the programmable oscillator.  
Removed the coupling cap and ran straight to 
the transistor base, removed the Collector to Base 
biasing and now running it sorta Class "C."
Replaced the broadband output transformer with a 
slug-tuned quarter-inch link-coupled coil that plugs
directly into the crystal socket and uses the circuit
capacitance to resonant.  As the coil is resonated,
you can see the 6L6 go from simply amplifying
and break into oscillation, locked to the programmable
oscillator's output.

Haven't gotten around to changing the Emitter circuit 
or perhaps replacing the base bias resistor with an 
RF choke- worried about how much current the 
programmable oscillator can source and the data
sheets aren't very clear on that.  Going to feed one
into an RF choke and pot and watch on the scope to
see "how low can you go" with the resistor before
the output of the oscillator starts crashing.
Still some tinkering to do but it's already much better.
https://goo.gl/photos/k886ZgFYF4vN3uKR8

A good crystal will result in 5 to 6mA of grid current at 
the 807 finals, resulting in 150mA of plate current and
about 45W out on 3890 KC.
The current itteration of the crystal subber results in 
between 2.5 and 3mA of grid current, about the same
150mA of plate current and just over 40W out.
Rules of the road:  Substitative changes in the 6L6 
oscillator stage are forbidden.

Questions:
Because the average plate currents are nearly identical, 
can one assume that 3mA is sufficient grid drive and that
the crystal just drives the 807s deeper into Class C?

If both methods result in avg 150mA of plate current,
is the difference in output due to the duty cycle of 
"just in Class C" with the subber verses
 "deep in Class C" with a crystal?

I'm going to keep working with this until I get
at least 5mA of PA grid current. 
 Just got to find the right transistor, I guess.

TNX OM DE Dave AB5S