[Johnson] The fun of hollowstate electronics

[KENNETH A CRIPS]

One thing I find interesting. Look at the catalogs, and spec' sheets for the 
transformers used in the radios of the 50's, you will note they are designed 
for specific tubes. The Parts Viking II I have was transmitting with 6146B's 
and had been for many years. It did not have the original modulation 
transformer, and there other Mod's I had no documentation for. it was also 
modified in the audio from end to take a 12 series 9 pin tube I was never 
able to ID. I understand this Viking II finally fell into the clutches of a 
chicken bander who promptly detonated it. I am sure the Viking II could be 
rebuild to use the 6146B but I really can't see the point tubes it is happy 
with are still in good supply.

I have sure have learned a lot about old transmitters.  My first love are 
old Ham receivers. There are only so many ways a tube type transmitters can 
be constructed.
Receivers on the other hand are so diverse. It is very interesting to 
contrast the engineering between them.  Look at the 51J3 Collins and a SP 
600 Hammarlund both are contemporary designs both do the same job but they 
couldn't be more different. The Super Pro has the most deliciously smooth 
tuning, but the 51J3 has a superior slide rule tuning arrangement, which 
when calibrated made such devices as the BC 221 frequency standards 
unnecessary.  The Collins trademark PTO (permeability Tuned Oscillator) and 
tuning slugs are superior to the air variable cap's and the awesome band 
switch turret the Super Pro has. The 51J3 is easy to work on. Working on the 
SP 600 has been described to be like working on an 8 layered burrito.


Kenneth A. Crips Station W7ITC, Cheyenne, Wyoming.