[GreenKeys] Model 12s

[DR HOUSE]

Very well Jim,
But history is important.  It is also of note that the Model 12 was  
the first commercially
successful teletypewriter. Being tried out by a railroad* but the  
first big customer was the Associated Press.
The 12 I have in California has AP tags on it as does the 20 here in  
Ringwood.
I guess I am preaching to the choir.  Your comments are always greatly  
appreciated here.

Best,
Don
* was it the Chicago & Alton RR?


On 7 Jan 2012, at 6:44 PM, Jim Haynes wrote:

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.