[GreenKeys] Differences between US Army & Navy TTY communications

Sun Apr 9 10:52:25 EDT 2023

QSL

That "ship-75a" figure gives a good feeling for the complexity of a Navy 
shipboard comm setup.

Duncan
K2OEQ
.

On 08-Apr-23 21:01, Nick England wrote:
> Yes big differences between Army and Navy ops at the unit level. Big 
> message processing centers were more alike.
>
> When the Navy ran full duplex it was to separate TTYs, one for 
> transmit and another for receive. Nobody tried to type on the machine 
> that was printing, except for cutting tape which functioned via direct 
> mechanical keyboard to perf connection and didn’t interfere with 
> printing. Then when it was your turn to transmit, you would run that 
> tape through the TD.
>
> The UGC-6 (28ASR) was used in duplex systems as a transmitting TTY 
> while another TTY was printing (or punching tape).
>
> Mainly, ships received the fleet broadcast on TTY printers. There was 
> no transmission back from the ship, just reception of messages from 
> shore stations.
>
> Ships also participated in nets, but that wasn’t full duplex.
>
> Even a smaller ship might have 10 TTY units aboard (counting TD, ROTR, 
> KSR, ASR)
> https://www.navy-radio.com/ships/images/ship-75a.JPG
>
> Disclaimer- this is from what I have read and studied. I have no 
> first-hand operational experience.
>
>
> On Sat, Apr 8, 2023 at 7:38 PM Duncan Brown <duncanancy at earthlink.net> 
> wrote:
>
>     In digging into a M28 ASR, I think I have stumbled across some of
>     the differences between Army & Navy TTY communications.  All the
>     schematics for M28 KSR & ASR units that I have seen, show just one
>     loop, tying the TX & RX circuits together. (Aux reperf in a M28
>     ASR typically has its own loop.)  M28s are wired such that they
>     are very flexible and can be wired to separate TX & RX circuits,
>     but that is typically not how they are shown on system drawings. 
>     Th AN/UGC-6 (M28ASR w/aux reperf) schematic (fig 12-38 from the
>     Navy manual ) does not show an option for full duplex (separate TX
>     & RX loops) operation.
>
>     Nick says that full duplex was not used much (if any) in the Navy
>     TTY comms, but his page, https://www.navy-radio.com/circuits.htm
>     does mention full-duplex operation.
>
>     In 1950, the Army (and Army-Air Force) started buying Kleinschmidt
>     equipment exclusively (although they did buy some  M28s later.) 
>     All the Kleinschmidt units, TT-4, TT-76, TT-98, AN/FGC-25 were set
>     up for full duplex operation with separate cables or jacks for TX
>     & RX. The standard Army wire-line modems (TH-5 & TH-22) used with
>     the TTYs were capable of both simplex (2-wire) and full duplex
>     (4-wire) operation.  Mobile RTTY huts (AN/GRC-26, -46, -122) could
>     all be operated full duplex, though simplex was the norm. (the
>     AN/GRC-142 is a simplex GRC-122.)
>
>     I was a TTY repairman in the Army Security Agency. In Viet Nam in
>     1967. I was in the 337th Radio Research Co., supporting the 1st
>     Infantry Division. We were located near the Division HQ and had
>     outstations (AN/GRC-46 huts) positioned with the forward located
>     1st ID Brigades.  We also had a link to our battalion HQ and that
>     link carried a lot of traffic; so much so that it was run in full
>     duplex mode, with messages going in both directions, simultaneously.
>
>     The outstations had tape facilities (TT-76s), but our company comm
>     center just consisted of a hut (AN/MSA-?) with four TT-4 printers,
>     4-5 KW-7 crypto units and four TH-5 modems in it. So all outgoing
>     messages had to be typed on-line.  Imagine typing a message on a
>     printer while another message is being printed!
>
>     The Army did have medium-sized comm centers in trailers or vans
>     and big, fixed station comm stations, but I never saw them. I did
>     work on a 12 channel tape-relay center that was in a 38 ft trailer..
>
>     So maybe some of the difference between Army & Navy operation was
>     due to the Army units being smaller and more spread out; vs. the
>     Navy with concentrations of operations on big ships. The Navy's
>     use of multiplexed RTTY may have given them enough channels that
>     they did not need to operate full-duplex.
>
>     Just some thoughts.
>
>     Have fun,
>
>     Duncan
>     K2OEQ
>     31J30
>
>
>
>     On 08-Apr-23 16:24, Nick England wrote:
>>     See also
>>     https://www.navy-radio.com/circuits.htm
>>
>>
>>     On Sat, Apr 8, 2023 at 4:13 PM Nick England
>>     <navy.radio at gmail.com> wrote:
>>
>>         They just weren’t used in full duplex (except if the aux
>>         typing reperf was independently connected). Normal
>>         installation was to the C-1004 box that you manually switched
>>         from CFS REC to CFS SEND. (The TONE position was for hookups
>>         that automatically keyed the xcvr, usually UHF).
>>         https://www.navy-radio.com/rtty/c1004.htm
>>
>>         I guess I just don’t understand when you would run full
>>         duplex using a single TTY.
>>         If you wanted to receive while transmitting you just used an
>>         additional TTY printer or reperf.
>>
>>         Read more about the Navy’s view of RATT
>>         https://www.navy-radio.com/journal.htm
>>
>>         And
>>         https://www.navy-radio.com/commsta/circuit/THE20GOLF20SYSTEM.jpg
>>
>>
>>
>
> -- 
> Nick England K4NYW
> www.navy-radio.com <http://www.navy-radio.com>
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