[R-390] Mint condition R-390A

[Charles Steinmetz]

Les wrote:

> The ceramic filters were from the 1960 EAC contract. They
> didn't meet specifications, production was stopped   *  *  *
> and they went back to the mechanical filters. Clevite was
> the filter manufacturer.

Oh, how right you are.  I've worked on 4 of these over the years, and 
the ceramic filters were just the pits.  All of the nasty, 
harsh-sounding ringing at the cutoff frequency like the Collins 
mechanical filters (more, actually, as I recall), and horrible stop band 
performance, as well.  These radios had the poorest IF and audio 
performance of all 390As (which already fell far behind the original 
R390/URR with its LC IF filters).  Truly awful.

The owners of the 4 receivers I worked on upgraded to standard filters 
and were astounded at how much of an improvement it made.

Rare?  Yup.  For very, very good reason.

Best regards,

Charles