[Milsurplus] Russ IL-14 aircraft w/ radios

[Hue Miller]

US-9 last production 1977? That is sorry. I don't think China even
was building any valved equipment that late. Well, i suppose it
helped maintain full employment.

Must be a record, since the initial BC-224-A model appeared in
1936.

Does the US-9 have a crystal filter also? If so- what kind of
circuit, does it look like the "old" or "new" BC-348 circuit.
I was thinking about the BC-348 crystal filter circuit: why even
have a crystal filter in an aircraft radio? Any jamming is going
to try to zero beat, and anyway who ever heard of any jamming
of the brief HF CW messages? Other than that, the military was
hardly likely to be operating in the 40 meter band on a contest
day. When they simplified the BC-348 for late production, they
could as well have removed the crystal filter entirely. I am thinking
of production-cost, not desirability for the surplus market! 
-Hue Miller