[HCARC] RTTY (or RATT for old Navy guys)

[SARA SANDSTROM]

More places to find articles about RTTY and TTY in general. 

When Wayne Green, W2NSD, was really W2NSD and not W2NSD/1, he was with CQ magazine and had a RTTY column which was quite good.  CQ also had numerous RTTY articles in those days.  Back then the ARRL had decided that RTTY wasn't legal for hams and didn't publish any RTTY articles.  When Wayne left CQ and started 73, many of the RTTY articles followed him. 

Cowan/CQ published "The New RTTY Handbook" in 1962.  It gas an excellent section on TTY machines and covers Model 12,15,26, and 28 Page Printers; Model 14, 19, and 28 ASR Tape (punched paper tape, by the way) Equipment; and Polar Relays.  The majority of the TU's in this publication are vacuum tube type but their general design is still of interest. 

The ARRL published "Specialized Communications Techniques for the Radio Amateur" in the mid 70's.  It had a fairly good section on RTTY including some classic solid state TU's and accessories.  It included the Mainline TT/L2 vacuum tube TU and the Mainline ST-4 solid state TU.  While the name Mainline may not mean too much, the solid state Mainline TU's were marketed commercially by HAL.  Later versions, the ST-5 and ST-6 initially appeared as construction articles in Ham Radio .  All the Mainline stuff is excellent in that the author takes great pains to explain how the TU works.  The author of the Mainline articles also ran a series in QST that was a great introduction to RTTY.  This was back in the 6 0's. 

Another great source of TTY and RTTY information is the Bell System Technical Journal (BSTJ).  The BSTJ is available on the internet.  I think its a Lucent site that currently has it.  These are not always easy reading as they were quite technical., however, they really go into the design of the equipment, both the machines and the electronics.  Some of the ones I've found interesting in the past are "Frequency Shift Telegraphy - Radio and Wire Applications" by Davey and Matte, Vol 27, page 265-304 (1948);  Performance Characteristics of Various Carrier Telegraph Methods" by Jones and Pfleger, Vol 25, page 483-531 (1946);  "Fundamentals of Teletypewriters Used in the Bell System" by Watson, Vol 18, page 620-639.  There are of course numerous others.  

QST has had numerous RTTY articles, mainly in the 60's and 70's.  If you are an ARRL member, you can go to the ARRL website  and download old articles from QST.  If you're not an ARRL member, shame on yo u.  Yes, there are a bunch of ding-a-lings up in Newington, but they are the onl y game in town  and they do provide some useful services.  Some good QST articles are "RTTY Reception for Beginners" by Blakeslee, Mar 1965, page 28;  the series by Hoff ( of Mainline fame) starting in January of 1965 and finishing in Nov 1965;  "The Mainline TT/L-2 FSK Demodulator" by Peterson, May and Jun 1969 (Yes, its tubes, but it includes discussion of using 88 mH loading coils to make audio filters for RTTY);  "The Mainline ST-3 RTTY Demodulator" by Hoff, , (also includes the ST-4);  "AFSK for RTTY, Introducing the "Mainline AK-1"" by Hoff, feb 1969;  "A Universal RTTY Current Loop Interface" by Nafziger, Jan 1984.  Hoff also had a n article on building RTTY filters, but I d on't have the reference handy.  It was in QST in the early 60's. 

Ham Radio magazine has also run several articles on RTTY equipment.  I don't think Ham Radio is quite as easy to find.  Your best bet is to find someone who has copies of the old magazines.  The two of most interest are "The Mainline ST-5 rtty demodulator" by Hoff , Sep 1970;  "The Mainline ST-6 RTTY demodulator" by Hoff, Jan 1971;  and "Troubleshooting the ST-6 RTTY d emodulator" by Hoff, Feb 1971.  The se 3 articles are the HAL ST-5 and ST-6 TU's.  Ham Radio also had numerous articles on phase- lock  loop RTTY demodulators.  I don't consider the phase lock loop approach worthwhile for HF conditions with fading noiose and interference, but if you want a cheap simple RTTY demod, you shouldn't have any trouble finding a PLL version.  Typically the PLL units use an XR2211 or NE565 IC. 

73, 

Kerry