[GreenKeys] Model 12s

[Gerry Block]

I think mine says "UPI" on the front (under the re-paint)
Gerry




________________________________
From: Jim Haynes <jhhaynes at earthlink.net>
To: DR HOUSE <Packard42 at gmail.com>
Cc: greenkeys at mailman.qth.net; david freeman <_dave.f at mail.com>
Sent: Sat, January 7, 2012 4:44:36 PM
Subject: [GreenKeys] Model 12s

It seems that the early amateur RTTY work was largely based on Model 12s,
using VHF, in the NYC area.  I heard somewhere that the NYPD had replaced
its Model 12s with more modern equipment around the end of WW-II because
Teletype had quit making spare parts for the 12s.  And Bob Weitbrecht
W6NRM told of getting his first machine, a Model 12 RO, from a newspaper
in the Los Angeles area; so I guess the press wire services also were
using their 12s until the end of WW-II when they could get 15s and could
no longer maintain the 12s.

Except for their age and worn condition Model 12s were tolerable for VHF
RTTY.  When hams tried to use them on HF there were lots of problems with
RFI.  One solution was to use vacuum tubes to drive the printer magnets.
There was also a vacuum tube modification for speed governed motors to
reduce the RFI.

But as soon as hams started getting better machines they dumped the Model 
12s.  Chief among the better machines were Model 26s, which the telephone
companies started phasing out in the 1950s when Teletype was allowed to
quit making spare parts for them.  In the 1950s we weren't very interested
in preserving history.  And Model 12s were not really very nice machines
to have.  Aside from the RFI problems, and the distributors needing
adjustment, they were made from typewriter parts and were pretty well
beat to death by the time hams got them.  I personally put a couple of
M12 typing units into the garbage.  They were given to me by Ray Morrison,
and I had nothing but the typing units and observed that the bearings were
extremely worn, so that parts flopped around.


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