[GreenKeys] How long can a local loop be?

[Jim Haynes]

On Thu, 13 Jun 2019, Joe Herdler via GreenKeys wrote:
> 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?
I'm sure that would work fine.  Even with cable.  There are some 
transmission issues that I don't recall where they were running TWX over 
long loops.  On the web you can find a scanned book:
ATT_Principles_of_Electricity_1953_ocr.pdf
see 
https://www.scribd.com/document/180230957/Principles-of-Electricity-pdf
for one and I'm sure there are other copies.
This will tell you more than you want to know about wire line telegraph
transmission.

Jim W6JVE