[GreenKeys] Continuing, nothing about Teletype art

Sat Sep 14 20:26:54 EDT 2019

Stories like this keep me on this list!

Peter

> On Sep 14, 2019, at 4:38 PM, Jordan Spencer Cunningham <js at teletype.net> wrote:
> 
> All,
> 
> Please keep sharing these stories, even if unprovoked. I love reading them, and we need to preserve them in history.
> 
> People who are bored by them can simply skip to the next email.
> 
> -
> Jordan Spencer Cunningham
> teletype.net
> 
> 
>> On Fri, Sep 13, 2019, at 8:03 PM, Jim Haynes wrote:
>> 
>> During the college years I had frequent contacts with Bob Weitbrecht,
>> W6NRM/W9TCJ who was then at Yerkes Observatory in Wisconsin.  A good
>> friend of his was a professor at Arkansas, "Charley" Fan, who had
>> recently left Yerkes, so I got them together on RTTY several times.
>> Bob was one of the great pioneers and promoters of RTTY, devising a
>> lot of equipment and traveling great distances to help hams get
>> started.  There was one period when he and BeeP W0BP traveled together
>> for a long distance, stopping to visit RTTY-ers all along the way from
>> Minnesota to Texas and beyond.  Bob was deaf, so ham radio was a great
>> social outlet for him, and RTTY made his communication a lot faster
>> than he could do with CW.  He decided to leave Yerkes and came to visit
>> us and the Fan family in Arkansas before returning to California and
>> resuming use of his W6NRM call sign.
>> 
>> I enjoyed operating the RTTY contests in those early years.  There were
>> only two a year, and the number of RTTY operators was so small that many
>> of us were acquainted with one another outside of the contest periods.
>> Also W5YM was the only RTTY station in Arkansas, so everybody wanted to
>> work us for the section multiplier.
>> 
>> When I told Merrill I had a summer job at Teletype he told me to look up
>> Bob Reek there.  He and Bob had been roommates at some summer short course
>> on transistors put on by some university not long before.  As it turned
>> out Bob was my immediate supervisor both summers when I worked there.
>> He is still living and we are still in touch.
>> 
>> Although Teletype Corp. was not in the radioteletype business we were
>> working on time-division multiplex equipment for the Navy to use on RTTY.
>> This was my first chance to work with transistors in large quantities.
>> I didn't take to transistors very well in linear circuits since they were
>> so hard to bias and stabilize.  But we were using them as switches in
>> digital circuits where they really excelled.  At the time transistors
>> were too slow to use in digital computers, so we were working with and
>> manufacturing logic circuits ahead of the computer industry.
>> 
>> As to the original subject matter of this posting, RTTY art, I never
>> paid much attention to it because on HF there are enough hits and dropouts
>> to spoil just about any attempt to transmit pictures.  Plus it takes up a
>> lot of time that could be spent in conversation about RTTY.  I guess
>> RTTY art was more practical in areas where there were a lot of hams 
>> operating VHF where copy was consistently good.
>> 
>> Back then in addition to amateur RTTY there was a lot of other stuff on
>> the air we could copy.  I remember when Sputnik went up we were very
>> busy at W5YM copying all the press we could find and hanging it on the
>> door outside the ham shack for the passers-by to read.
>> 
>> In the Air Force I had my own RTTY station, first in the garage of a 
>> friend who was married and had a house on the base, and later in my room
>> in the BOQ.  I used the Model 15 I had put together from parts from W9GRW,
>> and an old BC-375 transmitter modified to use a Heathkit VFO.  Receiver
>> was initially a BC-348 and later a Drake 2B.  Later Bob W6NRM gave me
>> a transmitter, Royal Canadian Air Force I think, that was less ponderous
>> than the BC-375.  It was intended for use with an external modulator
>> for AM, so the transmitter alone was a fine CW and RTTY performer.
>> 
>> After the Air Force I went back to Teletype full time.  I set up my RTTY
>> station and had a lot of contacts with Irv Hoff who moved to California
>> sometime in that period, and with Vic Poor at Frederick Electronics Corp.
>> I didn't really contribute to the design of the ST-6 and the Frederick
>> demodulators, but it was interesting to keep abreast of what those guys
>> were doing.  We had a ham club at Teletype, and I occasionally attended
>> meetings, but for some reason I never got over to the building where the
>> club station was located.
>> 
>> After 3 years at Teletype in Skokie I went with G.E. when they were in
>> the computer business in Phoenix.  I learned a lot about computers, but
>> working for G.E. was a lot less fun than Teletype, at least for me.
>> After two years of that I landed a non-academic engineering job with
>> University of California, Santa Cruz and stayed there for 30 years.
>> On the faculty were Harry Huskey, a computing pioneer who had worked on
>> ENIAC, and David Huffman, famous for the Huffman codes and a lot of
>> other important things.  And continued RTTY in my spare time.  I had a
>> housemate WA6JYJ who was a friend of Bob Weitbrecht and whom the 
>> university hired when he got out of the Army.  Bob lived just about an
>> hour away in Redwood City, so we got to visit each other often.  By
>> that time Bob was quite absorbed in the modem he had invented for use
>> over phone lines by deaf people with TTY machines.  But that's another
>> story.
>> 
>> This was the period of time when integrated circuits became cheap, so
>> we could develop a lot of stuff for RTTY quickly and easily.  One thing
>> I built was a speed converter so that a Model 28 running at 100 wpm
>> could copy any of the standard speeds.  Larry WA6JYJ also built one with
>> a few changes from mine and wrote it up for Ham Radio magazine.
>> 
>> I was also interested in the possibility of improving RTTY reception
>> by using a more advanced detector, one taking advantage of synchronism
>> to know when the big boundaries were going to occur.  The FCC rules for
>> amateur RTTY had never permitted us to transmit anything other than
>> 7.0-7.5 unit start-stop code.  After a while I realized that I could
>> transmit 7.0 unit code synchronously, putting in a fill character 
>> whenever there was nothing available in time from the keyboard or tape
>> reader.  I built a circuit to do this and started using it on the air.
>> I had a collaborator who was supposed to be working on a receiver for
>> the signals, but I don't know if he ever got it working.  In any event
>> the guys who were experimenting with and using two-tone demodulation
>> really liked it because it prevented the loss of space tone when a 
>> keyboard user quit typing.  I believe this is the origin of the "diddle"
>> style of RTTY signaling that is almost universally used today.
>> 
>> I was really tickled many years later when I read of K6STI and his RITTY
>> software that demodulated RTTY on a PC and that had what he called a
>> "digital flywheel" that would synchronize to a repetitive FSK signal
>> regardless of the length of the stop bit.  This was what I had hoped
>> to achieve with my diddler circuit and a purpose built hardware
>> synchronous demodulator.  Well RITTY was a very good demodulator, but
>> the improvement we were hoping for did not materialize - the synchronous
>> detection only helped a couple of dB of signal-to-noise ratio.  I found
>> an old government report where Stromberg-Carlson had developed a system
>> for the Army that was pretty close to what I had in mind, back in 1958.
>> The abstract to the paper reported a great improvement over standard
>> FSK operaton.  I was able to obtain a copy of this report - having to
>> use a FOIA request to get it.  It turned out that real synchronous
>> detection didn't seem to help at all, because propagation through the
>> ionosphere introduces so much variation in the arrival time of signals.
>> 
>> > I hope that my rambling is not boring to any or many.  It is great to think
>> > back to that time of my life and remember the 'good times'
>> > along with the bad times.  The nearly two years I spent on the USS Hancock
>> > were most interesting and educational for me. 
>> > 
>> Not boring to me, and I hope my attachments are not boring to the group as
>> well.
>> 
>> Jim W6JVE
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> 
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