[GreenKeys] on-off radio teletype (not FSK)

[Wa3frp]

Make and Breaking keying was all that hams had on HF radio after WWII, 


The FCC, in 1953, amended the regulations to permit FSK in the non-voice parts of the 80, 40 and 20 meter bands and also specified the use of single channel 60 words-per-minute five unit code corresponding to ITA2. A shift of 850 hertz plus or minus 50 hertz was specified.  Use of this wide shift proved to be a problem for Amateur Radio operations. Commercial operators had already discovered that narrow shift worked best on the HF bands. After investigation and a petition to the FCC, Part 12 was amended, in March 1956, to allow Amateur Radio Operators to use any shift that was less than 900 hertz.

Pretty much everything was 850 Hz shift until the late 1960s when the move to 170 Hz shift occurred almost overnight, thanks to the efforts of Irv Hoff and others via the pages of RTTY Journal.  There was a phrase used then, "Be broad minded, use narrow shift"



73
Russ - WA3FRP
wa3frp at aol.com

i-Telex 834328 WUTMPAM CHIL



-----Original Message-----
From: Nick England <navy.radio at gmail.com>
To: Greenkeys <greenkeys at mailman.qth.net>
Sent: Fri, Feb 16, 2018 5:01 pm
Subject: [GreenKeys] on-off radio teletype (not FSK)




How common was on-off radio teletype (not FSK) back in the day?

Did hams ever use it or was it strictly a military or commercial thing?


This question poked up in my mind as I was scanning the manual for a 1952 RTTY converter designed for 60-600 wpm on-off keying.
http://www.navy-radio.com/manuals/r466-uc-man-91612-5202.pdf

One block diagram shows it being used to receive on-off tone signals via VHF that were generated originally from an AN/FGC-5 which is a gadget that time-multiplexes four TTY lines together. 






Nick England K4NYW

www.navy-radio.com





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