From: Ian Sparkes <ian.sparkes@t-online.de>
Date: Wed, 8 Oct 1997 23:51:39 +0800
To: cypherpunks@toad.com
Subject: Re: Internet Via Electric Lines?
In-Reply-To: <199710081351.GAA15055@toad.com>
Message-ID: <3.0.2.32.19971008173309.006c5a34@q9f47.dmst02.telekom.de>
MIME-Version: 1.0
Content-Type: text/plain



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>> I heard on the ABC hourly news that some genius had figured out a 
way
>> to use electrical power lines for data transmission...

FM
>The FM signal has difficulty going through transformers (there are 
>lots of transformers, with the final step-down usually occuring at 
>a pole-top near your house).

This has been widely used as a (very) local area network - you can 
find a number of Hobby-style projects in electronics magazines dating 
years back.

The transformers, which are designed for 50/60Hz, should look like 
brick walls to any carrier frequency that can cope with a meaningful 
bandwidth. This probably explains why it is local. Additionally, I 
have heard that the power companies tend to get uppity about even the 
local variant - apparently it impacts their supply monitoring.
 

Optical
>[...] Putting a few optical
>fibers into a power line is cheap, easy, and widely done.

But much cheaper and easier is using the signalling gulleys that run 
along the side of the railways - no High Tension precautions, no 
scaling pylons. This, incidently is the reason that a number of 
telecomms consortia (in europe, at least) include a railway element - 
they provide the long-haul backbone.

[...]
>Also, employees have to be trained to splice optical fibers and
>install routing equipment, and millions of miles of power lines and
>hundreds of millions of junctions need to be replaced or reworked.

And that's the 'cheap & easy' mentioned above?



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