[R-390] EAC SSB Conversion

[Dennis Wade]

I have a Motorola receiver that I purchased about 20 years ago now from a
seller in Southern California.  It is all Motorola with the exception of
the small sub chassis behind the audio gain pot that contains the 6U8, 2
crystals and associated circuitry, and a modified EAC IF deck.  The IF deck
mods (that I can see) are the addition of a multi-pin connector (similar to
the connector used on the PTO) and cable that takes the signals to the mode
switch and takes care of switching the crystal BFO in and out of the
circuit, and signal routing.

I can't say for certain if there were any AGC changes made because I
haven't taken the time to trace it out.  My perception is that there were
none.  There is still some need to "ride" the RF gain to prevent
overloading on peaks.

There are no other markings on or in the radio to indicate that Columbia
(or whoever else for that matter) did the mods.  The front panel was
professionally re screened with added mode positions.  Unfortunately, I
didn't ask or get any information on its past when I bought the radio.

I'm happy to answer what ever questions I can.

                 Dennis


On Tue, Apr 30, 2013 at 11:54 AM, Dennis Deaton <wa6acc at verizon.net> wrote:

> Good Morning to the List,
>
> Several years ago, an article was published giving both the picture and
> the schematic that EAC had produced for a foreign military's mod to the
> R-390A to give it good SSB reception. It involved building a small
> crystal-controlled BFO and product detector using a 6U8. Does anyone on the
> list have that data? If not, could you point me to it?
>
> Many thanks,
>
> Dennis Deaton, WA6ACC
> Redlands, CA
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-- 
"If they trust you, it is an extraordinary privilege, and you simply can't
abuse it."
      - A. Alan Post  1914-2011.  California Legislative Analyst 1949-1977.

-------------------------
Dennis L. Wade
KG6ZI
Carmichael, CA