[R-390] flying R390A

[Bill Hawkins]

Kenneth G. Gordon said, in part,

"While they are a good little receiver, they have their share 
of problems, among others, the mechanical filter center 
frequency is somewhat odd."

Back when I was buying R-390 class receivers as the peak of
vacuum tube technology, I looked at a 648 and said, "No thanks."

Aircraft radios pack things so densely that they are impossible
to work on, unless you are blessed with infinite patience. An
odd filter frequency was the least of the problems that I saw.

Regards,
Bill Hawkins