[R-390] Unusual ? Front panel

Thu Jun 20 02:47:11 EDT 2013

I have a Motorola with the modified IF deck and added module as well as the
schematic from Paolo's book.  It is quite clear, translation isn't really
necessary to make sense of it, although I'm sure a translation would be
helpful.  Its a simple crystal oscillator using half of a 6U8 with two
switched crystals.  The output is injected when the mode switch in placed
in the USB or LSB position.  In SSB, the IF signal is routed to the second
half of the 6U8 which is wired as a product detector.  For AM/CW, the
module is switched out and the IF signal is routed around to the stock
detector for AM/CW reception.  The switching scheme is as complicated as
the module (not).

As far as performance is concerned, it does a better job in my opinion than
a stock 390A..however I haven't been able to find any modifications to the
AGC system, so that fact still needs to be addressed in any SSB conversion
attempt.  Never the less, it is quite convenient to be able to switch
sidebands from the front panel.  The audio quality is still superior with
the product detector in my opinion.

You will also note that there are no changes to the filtering scheme...that
is the filters are still AM/CW, and not LSB/USB which would be another
improvement in receiving SSB.

                     Dennis

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

On Fri, Jun 14, 2013 at 12:16 PM, KR4HV <kr4hv at numail.org> wrote:

> It is curious that by now no one appears to have translated the Italian
> description in English along with a schematic and parts list.
> This lack of information in English begs the questions:
> a. Did the conversion work as hoped and work well?
> b. Was it worth the effort v.s. other schemes?
> c. Does anyone know?
>
> Regards,
>
> Walt
> KR4HV
>
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of Tom Bridgers
> Sent: Thursday, June 13, 2013 9:08 PM
> To: k2cby at optonline.net; R-390 Group
> Subject: Re: [R-390] Unusual ? Front panel
>
>
>
>
> These panels are the result of Columbia Electronics work in updating and
> restoring R-390A's for certain 3-letter  US govt.
> agencies and for a few Latin American countries.  I have several of the
> Columbia Electronics nameplates that I purchased from Dick Walser who was
> the prime sub- contractor doing the work..
>
> He and his business partner designed the module that is an add on to the IF
> deck which produces the capability to switch from Lower SSB and Upper SSB.
> Somewhere in my files, I have a circuit drawn by Dick, but it is also
> available in PaoloViappani's book, R-390-URR - R390a-URR handbook.The book,
> written in Italian,  appears to be available from: Amazon.co.uk.
>
> I also have one of the panels designed by Dick with the nomenclature you
> describe.
>
> Dick Walser, in North Hollywood, CA, was the subcontractor in that work.
> His company was named Airborne Electronics.
>
> I visited Dick about 15 years ago, and spent a delightful two days with he
> and his lovely wife, Dede, talking about the old days and looking over his
> incredible collection of R-390A parts.
>
> Until his death about 5 years later,  I was one the phone with Dick several
> times a month seeking his advice on this or that problem I was having
> trying
> to restore a R-390A.  He had an encyclopedic knowledge of the R-390 and
> R-390A, and was a genuine pleasure to have a conversation with.
>
> Another person on this list had the great fortune of purchasing all of
> Dick's parts, most of which unfortunately were lost in a shipping disaster
> when they were shipped to his new home in Texas.
> Best,
> -Tom
>
>
> > Date: Thu, 13 Jun 2013 18:46:37 -0400
> > From: k2cby at optonline.net
> > To: R-390 at Mailman.qth.net
> > Subject: [R-390] Unusual ? Front panel
> >
> > What R-390A version/contract had the words "UPPER"  "BFO"  "LOWER"
> > stenciled where the BFO frequency normally appears and the words "AM"
> > "CW - SSB" stenciled where "BFO OFF-ON" normally appears on the front
> > panel? Was this an "after-market" conversion? Who were these units sold
> to? Foreign?
> > Spookdom? How many were produced? Does it indicate that the BFO was
> > crystal-controlled? Was there a product detector included? Has anybody
> > got a print?
> >
> >
> >
> > Miles B. Anderson, K2CBY
> > 16 Round Pond Lane
> > Sag Harbor, NY 11963
> > Tel.: (631) 725-4400
> >
> > Fax.: (631) 725-2223
> > e-mail: k2cby at optonline.net
> >
> >
> >
> >
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