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

Fri Jan 12 16:24:03 EST 2018

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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