[Amps] Class C amp for RTTY contesting...

[Tom W8JI]

I have a few questions about this idea:
What would be needed to convert a "traditional" linear 
(AL-1200, AL-1500, L-4B, TL-922, etc) to strictly Class C 
operation?>>

Too much work.

Is there a specific tube (or tube series) that would be more 
efficient when run in this class?>>

Yes, a low mu grid driven triode with very high peak 
emission current.
You want a tube that can produce very high current pulses 
(very low anode to cathode "on" resistance) without damaging 
the tube. You want a switch, not a linear tube.

What efficiency could be expected?>>

If you play your cards right, about 90% or more. The 
theoretical limit is right at 100%. RCA made a BC 
transmitter that ran in the lower 90% range. It was a low mu 
triode with third harmonic resonators in the anode and grid. 
We had one at WSPD that had a very slight metering error in 
three of the meters, and it calculated to be 102% 
efficiency. :-)

Class AB at the edge of B can be over 70% in theory. As I 
recall about 75%.

Does Class C provide more/less gain (drive power) to obtain 
1500 Watts output?>>

Generally speaking less gain.

Don't try to run CW through it though!

73 Tom