[Qcwa] WWII RTTY

Tue, 5 Aug 2003 09:18:36 -0500

They Teletypes look like model 15's.  I don't know what the military
nomenclature was.  They were 5 bit, 60 baud machines, all upper case
characters.  You used the shift key to access the numerics & punctuation.
much of the transmission was done with a model 19 perforator.  A paper tape
was punched & then run through the machine which read the hole pattern &
sent the message.
As I recall there was no real switch from transmit to receive.  The units
ran on a 20 (or occasionally 60) MA loop.  The keyboard generated the
characters which operated a set of magnets on the machine.  The hardware
didn't care where the current switching originated.  Data coming down the
line printed as readily as locally generated stuff.

The actual signal was generated by a portion of the machine called the
distributor.  A motor rotated a shaft that ran a brush over a set of
segments that were either connected, or not, depending on the character to
be generated.  That produced the "Mark-Space" data to be sent.  Each
character was preceded by a start bit, and ended with a stop bit, so
synchronization only had to be maintained for the duration of one character.
The same motor provided the power to drive the print mechanism, which was
the same as an old style typewriter.  Moving bars that came up to strike a
ribbon & the paper.  At that time, Teletype Corporation (AT&T) held the
patents on the hardware but others were also licensed to build them for the
war effort.

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of [email protected]
Sent: Tuesday, August 05, 2003 7:39 AM
To: [email protected]
Subject: [Qcwa] WWII RTTY

Hello All:

My father was on Biak island (Dutch East Indies), 142 AACS, late in the war.
Dad was a "trick chief" a shift supervisor of the TTY operators.  He was
administrative and didn't know much about the gear and I never worked RTTY,
so I'd like to pose a couple of questions to the group.

(A photograph of the TTY/CRYP room is at the following URL:
http://home.att.net/~ka2e/dad/pic54.jpg)

a.  Can anyone identify the TTY gear at the right?
b.  What type/power of transmitters/receivers would have been used?
c.  How were the TTY machines interfaced to the transmitter/receiver?
d.  What frequencies were used?
e.  Generally, how did the TTY machines operate? I'm told they punched a lot
of traffic on paper tape and sent it later.  Communication was also done
directly at the keyboard - how did they switch between transmit and receive?

Many thanks for your help.  I feel it important to preserve as much WWII
history as possible because I can't forget that the comfortable lifestyle
that my generation enjoys was purchased by the sacrifice of the WWII
generation.

Best 73 de KA2E.

--
Mike
http://ka2e.home.att.net
_______________________________________________
QCWA mailing list
[email protected]
http://mailman.qth.net/mailman/listinfo/qcwa