[GreenKeys] Tri-tone RTTY

[Nick England]

FWIW - The USN multi-channel fleet broadcast used two tones separated by
1360Hz
e.g. 425+1785, 595+1955, 775+2125, etc.
So a 16-channel multiplexer could carry 8 channels of TTY info. (85 Hz
shift on 170 Hz centers)
The standard shipboard AN/UCC-1 frequency division multiplexer also has
switches to enable quad diversity.

Nick England K4NYW
www.navy-radio.com


On Fri, Nov 17, 2023 at 1:03 PM Sheldon Daitch via GreenKeys <
greenkeys at mailman.qth.net> wrote:

> On the subject of keying multiple sets of tones with the same data, in the
> long gone days of the Voice of America RTTY schedules, thoe AFSK circuits
> on HF did indeed use two sets of tones keyed with the same data.
>
> I can't tell you what equipment was used at VOA locations other than
> Greenville, but at Greenville, we used Northern Radio Type 153 tone keyers
> and the Type 174 tone convertors.  There were two sets of tones, a low pair
> and a high pair, 85 Hz shift each.  I wish that I had kept notes on the two
> pairs used, but I don't know the tones frequencies involved.
>
> Another form of RTTY diversity was time diversity.   There may be other
> systems involved, but Barry Research marketed their 6028 system for very
> critical TTY communications over HF links.   I found this link for the BR
> system:
>
> https://www.sigidwiki.com/wiki/BR-6028
>
> Enjoy.
>
> 73
> Sheldon
>
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
> >>> Jordan Spencer Cunningham's GreenKeys Search Tool:
> https://teletype.net/gksearch
> >>> 2002-to-present greenkeys archive:
> http://mailman.qth.net/pipermail/greenkeys/
> >>> 1998-to-2001 greenkeys archive:
> http://mailman.qth.net/archive/greenkeys/greenkeys.html
> >>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
> http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to navy.radio at gmail.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20231117/32b664b4/attachment.html>