[Collins] 6DC6 substitute

[Dr.Gerald Johnson]

The base of the 6GM6 is the same as the 6DC6. The GM6 has twice the 
gain of the DC6, which could lead to regeneration. The GM6 also cuts 
off at about 3 volts bias while the DC6 takes 10 volts to get it close to 
cutoff. The GM6 has a greater input capacitance making alignment at 
the top of 10m a little more bother.

The extra gain will put a stronger signal at the mixers which will then 
overload easier while the greater sensitivity to AVC voltage can cause 
the RF stage to fall faster than the designer's intended with AVC 
voltage. That conceivably could lead to AVC motorboating.

I'm sure there are those who didn't notice the mixer overload or AVC 
pumping and so think the 6GM6 is a better replacement for the 6DC6.

The 6GM6 will probably work with these caveats.

73, Jerry, K0CQ

-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.