[Boatanchors] VFO's??

[Brian Clarke]

Hi Stephen,

The original BC-457A fed the output of the 1626 oscillator tube, via a transformer, to the 
grids of the 1625 PAs. Some mods, required by licensing authorities, got around the 
unbuffered PA effect by feeding something like a 12AG7, that in turn fed the 1625s. The 
12AG7 was usually wired in place of the 1629 indicator tube.

To feed the cathode of a 6L6 would require a different impedance matching transformer - 
the parallel grids of the 1625s, even in Class C, would be much higher impedance than 
the cathode of the 6L6.

Why would you want to feed the output of a VFO to a xtal controlled oscillator? The 
BC-457 was not xtal controlled - the xtal there was used as a calibration marker, usually 
by ground or base staff. I don't think the BC-457 was ever expected to be tuned while 
being carried on a weapons platform.

If there is an octal power connector on your BC-457, that is a post-operational mod. 
Who knows what pin assignments were made? But taking the VFO output to one of 
the pins would not have been very unusual or difficult.

73 de Brian, VK2GCE.