[RTTY] A Wikipedia quote.
chen at mac.com
Thu Jan 28 23:51:44 PST 2010
While searching for references to ASCII radioteletype, I found this quote at http://en.wikipedia.org/wiki/Radioteletype :
> On January 7, 1972, the FCC amended Part 97 to allow faster RTTY speeds. Four standard RTTY speeds were authorized, namely, 60 (45 baud), 67 (50 baud), 75 (56.25 baud) and 100 (75 baud) words per minute. Many Amateur Radio operators had equipment that was capable of being upgraded to 75 and 100 words per minute by changing teleprinter gears. While there was an initial interest in 100 words per minute operation, many Amateur Radio operators moved back to 60 words per minute. Some of the reasons for the failure of 100 words per minute HF RTTY included poor operation of improperly maintained mechanical teleprinters, narrow bandwidth terminal units, continued use of 170 Hz shift at 100 words per minute and excessive error rates due to multipath distortion and the nature of ionospheric propagation.
I found the last sentence interesting :-). Notice also the comment on "narrow bandwidth TU." Be sure to open up the filter bandwidths if you try 110 baud ASCII and not fall into the same trap.
More information about the RTTY