[Milsurplus] What is it?

[KD7JYK DM09]

I was mulling this device over while eating my sub-C-Ration microwave 
lasagna....

It only requires three wires to operate, no doubt ground, filament and plate 
voltages (no manual keying as I thought).  I'll get the tube specs, assume 
the low voltage side is the filaments, and I assume the clockwork motor is 
driven from this as well.  Running low voltage only should get the motor 
going at the right speed without activating the transmitter, then I'll see 
about pulling the serial data out of it.

Kurt