[Milsurplus] BC-230 questions and observation

[Kd6b@aol.com]

All,
The tank circuits on the 230 and GF-11 etc appear to have been designed 
assuming that the short antenna would place a capacitive load across the tank 
circuit. On the low freq end of the coils they usually will not even resonate 
if there is not that added capacitance.
The tank ckt turns ratio steps up the plate load resistance to allow a 
smaller capacitance to be used on the lower frequencies. That requires more 
inductance in the coil of course. I measured the turns ratio but don't 
remember it, and am right now at work and don't have my notes. The main 
primary and secondary are tightly wound and so the coupling is good in the 
BC-230/430. The GF-11 is not as well done because of the pp RF arrangement.
Note, I have found that 6A3s can be subbed for the super rare VT-62s but do 
require that the bias be lowered to put the modulators into class A 
operation. I think I used a 47K from 6A3 grids to ground to do that.
73
Ken