[GreenKeys] Copper Wire?

[Paul Wills]

I don't have the specific date but I believe that copper telephone wire was
not used until Thomas Dolittle developed a hard drawn copper wire that had
the necessary tensile strength.

A search on Dolittle and "hard drawn" should turn up a date.

I would guess that this was in the 1880's or 90's.  Certainly, transmission
characteristics of wire for telephone service were much more important than
for telegraph as there were not yet any ways to amplify voice signals.

PDW

----- Original Message -----
From: <jhhaynes at earthlink.net>
To: "Brooke Clarke" <brooke at pacific.net>
Cc: <greenkeys at mailman.qth.net>
Sent: Thursday, August 30, 2007 9:29 PM
Subject: Re: [GreenKeys] Copper Wire?


> I've read that for early telegraph circuits they didn't use copper,
> because aside from the cost it was of poor quality and had very low
> tensile strength.  Hence they used iron.  Wonder when they started
> refining copper electrolytically.
>
> Bell wire in my childhood, say late 1940s, was bare copper wire about
> 18ga wrapped with a spiral red and white waxed cotton thread.  Used
> for hooking up doorbells, but a lot of radio projects and such told
> you to use bellwire, because you could get it at any hardware store
> and it was fairly cheap.
>
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