[R-390] R-390A Modified For Synthesizer Input?

[Barry Hauser]

I have three of the R-1981's -- R-390A's with a TMC Mod Kit.  (I forgot the
number --  there's an adhesive metal tag on the front panel.  These have a
small metal box mounted to the rear panel containing a solid state PC
circuit board (including one or more IC's as I recall) with several BNC
connectors, plus two more BNC's added to the rear panel itself. There are
also a number of tee-connectors tapping into the MB (mini-BMC) cables here
and there inside the radio.

They don't look much like Todd's receiver.  As I recall, someone wrote that
this mod was to use a digital frequency counter with the '390A for added
accuracy, but seems there are more added connectors than would be needed for
that purpose.

Barry


> Todd,
>
> The R-390A with 3 BNC jacks sounds like an R-1981.   It is described at
> r-390a.net under "variations".
>
> Drew
>
>> >NASA used R-390A' s modified to use high stability frequency
oscillators.
> >Maybe another group member can expand upon this. Jon AB9AH

> >----- Original Message -----
> >From: <ToddRoberts2001@aol.com>
> >To: <r-390@mailman.qth.net>
> >Sent: Tuesday, November 26, 2002 9:26 PM
> >Subject: [R-390] R-390A Modified For Synthesizer Input?
> >
> >
> > > <PRE>I have some pictures of an R-390A receiver modified with a
special
> >jack panel
> > > on the rear panel with 3 BNC input jacks that appear to be inputs for
> > > external synthesizer control of the receiver. I was wondering if
anyone
> >in
> > > the list has seen an R-390A modified in this manner? I'm not sure if
> >there
> > > are any extra switches on the front panel to enable/disable the
special
> > > inputs on the back. Looks very unusual. To see the pictures type in
(or
> >copy
> > > and paste) these addresses :
> >members.aol.com/toddroberts2001/Item7.jpg
> > >      or             members.aol.com/toddroberts2001/Item8.jpg
> >Thanks
> > > for any info on this. 73 Todd Roberts WD4NGG.