[GreenKeys] How long can a local loop be?

[Ken Wiebe]

Where did the loop power come from?

On Thu, Jun 13, 2019, at 19:14, Duncan Brown wrote:
> Teletypewriters were originally designed to operate in DC loops with a 
> ground return.
> 
> The specification for the Signal Corp's TT-4/PGC-1 was 25 miles at 60 
> wpm and 15 miles at 100 wpm (depending on ground conditions). This was 
> with 60 ma loop and ground return.  This was machine to machine. They 
> did not use polar relays except in repeaters to extend the range.
> 
> have fun,
> 
> Duncan
> K2OEQ
> 
> On 6/13/2019 17:19, Joe Herdler via GreenKeys wrote:
> > Hi all,
> >
> > How long can a local loop be? Would a pair of TTYs work at a mile 
> > apart with twisted pair wire? Or would one need to start thinking 
> > about using a polar relay and dual current for mark and space? What 
> > would the circuit look like? At that distance (mile +), does one need 
> > to think about open wire and insulators?
> >
> > Thank you again!
> >
> > Best,
> >
> > Joe
> >
> > Consciousness affects the medium. Think happy, be happy, and happiness 
> > will follow you.
> >
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