[R-390] R-390A and the SP-600

Fri Jan 12 23:08:25 EST 2018

Thanks for the offer Norm. I'll be away for a couple of days. I'll see what
is involved in scanning and IF its a big cost deal, I may take you up on
your offer. It is all single sided, so that makes it a bit easier and the
pages are standard letter size. Of course, since it came from a micro film
slide, the printed pages are slightly smaller than letter size.

As a heads up, when I get a chance, I'll type up the TOC and forward.

On Fri, Jan 12, 2018 at 1:24 PM, Norm n3ykf <normanlizeth at gmail.com> wrote:

> Alan,
>
> I've got a scanner with an automatic doucment feeder. Happy to scan it
> if you'd like. Live in Binghamton, NY currently.
>
> Usually have the wide pages done at the local print shop. Easier that way.
>
> Norm n3ykf
>
> On Fri, Jan 12, 2018 at 4:04 PM, Alan Victor <amvictor at ncsu.edu> wrote:
> > Hi Tim, Bob, others.
> >
> > I had several inquires once I fixed the misunderstanding that this is
> paper
> > and not film!
> > Anyway, I brushed the document off and started looking through it again
> > after many years collecting dust.
> >
> > I have been working on an active tuning preselector and there is an
> > excellent treatment of broadband varactor tuned networks which is worth
> > posting. That said, I think I will look at the cost of scanning the
> > document or just scan it myself and send a pdf to the 390a reflector. Not
> > sure how large a file it would be, but certainly much less than a Y2K
> > manual! Alan
> >
> >
> > On Fri, Jan 12, 2018 at 12:19 PM, Tim Holzheimer <timholz59 at hotmail.com>
> > wrote:
> >
> >> Alan
> >>
> >> I would like a copy of the RADC-TR-67-216 document.
> >>
> >> Let me know.
> >>
> >> Thank you.
> >>
> >> Tim Holzheimer
> >>
> >> 73 de N6DIY
> >>
> >>
> >> ------------------------------
> >> *From:* r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net>
> on
> >> behalf of Alan Victor <amvictor at ncsu.edu>
> >> *Sent:* Thursday, January 11, 2018 2:47 PM
> >> *To:* Tisha Hayes
> >> *Cc:* R390A
> >> *Subject:* Re: [R-390] R-390A and the SP-600
> >>
> >> If any interest prior to the land fill or other Earth friendly paths.
> >> .
> >> I have an excellent copy from microfiche from the Rome Air Force
> >> Development Center
> >>
> >> *Preferred-circuit Techniques for Receiver Applications*
> >> Over 1000 pages Tech report no. RADC-TR-67-216.
> >> Date June 1967.
> >>
> >> Covers every conceivable circuit technique at the time for wideband
> >> receiver techniques; 1 MHz-10 GHz.
> >>
> >> Any interest, email me direct. 73' Alan
> >>
> >> On Sat, Jan 6, 2018 at 7:16 PM, Tisha Hayes <tisha.hayes at gmail.com>
> wrote:
> >>
> >> > I have had a chance to compare "a few" receivers. Presently I own;
> >> >
> >> > R-390A (three of them so there is some general opinions)
> >> > R-390
> >> > R-392
> >> > SP-200
> >> > HQ-129
> >> > SP-600 (JX17)
> >> > RF-590A (Harris)
> >> > R-3030 (Cubic)
> >> > CDR-3250 (Cubic)
> >> > RA-6790 (Racal, four of them)
> >> > WJ-8718 (Watkins Johnson)
> >> > 5650 (Telefunken, three of them)
> >> >
> >> > - It may seem like "a bunch" of radios but that is just the premium
> >> stuff.
> >> > I have a tendency to chase after perfection. (it may seem weird but I
> am
> >> > for-real, ask Perry, he knows me personally). Here is my opinion on
> the
> >> > Hammarlund family in comparison to the R-390A;
> >> >
> >> > The SP-600 was a fantastic radio that came out when AM and CW were
> king
> >> > around 1951. The design is reminiscent of the pinnacle of "knob
> turner"
> >> > radios and is a pleasure to use for SWL or BCB-DX listening. The JX17
> is
> >> > really not the "best model" of the receiver, it was designed to
> support
> >> > diversity pairing with another radio and some changes in the circuitry
> >> and
> >> > voltages were made. If the crystal filter is close to the IF
> frequency it
> >> > can be a decent radio but often the crystals have changed frequency or
> >> the
> >> > radio was mis-tuned somewhere along the line. It also has a big
> problem
> >> > with BBOD (black beauty of death) oil caps and the electrolytic (the
> cans
> >> > and the bathtubs) capacitors.
> >> >
> >> > I have tried a bunch of things on an SP-600. Taking B+ ripple down to
> the
> >> > single millivolt level with filtering changes, building the "Nuvistor
> >> first
> >> > RF" plug-in instead of a 6BA6 and fighting (the never ending) battle
> >> > against drive slippage between the frequency disk and the knob
> >> >
> >> > The SP-600 is "drifty" for the first few hours and it is definitely
> not
> >> > frequency stabilized but if you leave it on for a long night of
> listening
> >> > to SWL it is a pleasing radio to listen to. The sound is very full and
> >> > sometimes I just listen to AM-BCB at night for the background noise
> while
> >> > doing something else in the house. As has been said it is a pretty
> >> > "intuitive" radio except for the IF bandwidth that can be a little
> >> > confusing unless you read up on it first.
> >> >
> >> > -----------------------
> >> > The R-390A is almost a generation newer than the SP-600 and is meant
> to
> >> get
> >> > on a frequency and stay there. Probably more than a few people on this
> >> list
> >> > spent their times wearing green or tan, wearing boots and eating
> >> K-rations
> >> > while they maintained racks full of R-390's in RTTY service. It works
> >> great
> >> > for data, is not as deaf as the SP-600 at higher frequencies and can
> be
> >> > passably good with SSB with an external converter.
> >> >
> >> > The R-390A is not a knob spinner (we all know that) and I invested
> >> > significant time in to smoothing out the drive mechanisms, playing
> with
> >> > synthetic oils and tungsten disulphide to make it less straining on
> the
> >> > wrists. It has a better tube line-up in the RF deck and the advantages
> >> (and
> >> > disadvantages) of mechanical IF filters. I have added roofing filters
> >> > between the RF and the IF and rather than butchering the audio deck I
> >> just
> >> > pick off the audio and feed it in to the AUX input on a Telefunken
> 5650
> >> > receiver (fantastic audio quality).
> >> >
> >> > By itself the R-390A can be "tiring" to listen to all evening long. It
> >> has
> >> > a hard to describe "robotic" sound. One receiver does not have that
> >> effect
> >> > but it is a rare R-390A variant with ceramic filters in the IF.
> >> >
> >> > How I wish the R-390A had an SSB mode.. it might be another reason
> from
> >> > keeping me away from the Harris RF-590A that I have been increasingly
> >> using
> >> > for dial hunting to listen to the chatter on the geritol-net on 80
> >> meters.
> >> >
> >> > -----------------------
> >> > In the past six months or so I have been buried in Telefunken rebuilds
> >> and
> >> > while I read the postings on this list I do not contribute as much as
> in
> >> > the past.
> >> >
> >> > *Ms. Tisha Hayes*
> >> > *AA4HA*
> >> >
> >> > *Sr. Engineer, 4RF USA.*
> >> > ______________________________________________________________
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