[GreenKeys] Model 14 TD - weirdly coded transmission head

[Duncan Brown]

Tony,

Did that TD have two tape heads? Could it read two tapes simultaneously? 
(pic enclosed)
There was a time-division multiplex version of the M14, TT-26/FG used 
during WWII, that had two tape readers and about 14 sectors on the 
distributor. Each bit/sector was about half the normal length (ie ~11 
ms).  See TM 11-2222.

The two tape messages would be sent out on the same line. At the 
receiving end, two printers on the same line would have their Range 
Finders set to opposite ends of the range. One printer would copy the 
"early" bits and the other printer the "late"  bits.

If your mystery TD only had one tape reader, I don't know what it was.  
Sounds like your solution of connecting all the sectors together and 
then cutting them to the proper size should have worked.  The 
printer/reperf selector mechanism only uses the middle 4-5 ms of each 
pulse, so it should not have been that critical.

Have fun,

Duncan
K2OEQ


On 12-May-20 18:04, tony.podrasky wrote:
> GA Oms;
>
> When I got started in RTTY, after the model 15, I
> picked up a model 14 TD.
>
> I couldn't get it to work.
>
> When I showed it to someone they said that the
> transmission head was wrong.
>
> Instead of 6 22.ms bits (1 start / 5 data / 1 stop bit)
> it had something more like 6 11.ms bits (1 start / 5 data /1 stop bit)
> and the stop bit was huge.
>
> I tried soldering the entire ring together and then cutting it
> to fit the standard bit times, but when you're talking about
> MILLISECONDS, it's pretty tough to cut something that accurately.
>
> Has anyone seen something like that - and what was it used for?
>
> UE,
> K2EAA - TONY
> NNNN
> ZCZC
>

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