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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? -----BEGIN PGP SIGNATURE----- Version: PGP for Personal Privacy 5.0 Charset: noconv iQA/AwUBNDuntfzOjjBJiFUeEQLX+wCfZu20gO0gc2SahIGPm0+QRKjIDV0AoIhk 81RJqpql8IIKwZXOapVCZthK =8Una -----END PGP SIGNATURE-----