[TriLUG] OT: electricity and networks (a network question, really)

[Greg Brown]

I was checking out a neato article on slashdot about the nocat guys 
setting up a wireless network using ethernet over power cable to a 
small ether-over-power to 802.11 bridge.  This looked very interesting. 
  The article is here:

http://www.oreillynet.com/pub/h/352

And the ether-over-power to 802.11 bridge is here:
http://www.speedstream.com/products_powerline.html
(the Speed Stream 802.11 bridge)

Ether over power seems to be limited to 14 meg/sec, which is okay if 
all you are doing is 802.11b which is 11 meg anyway.  Now, the question 
is related to propagation of the ether signal over the power cables.  
I'm NOT a EE, nor someone with much of any experience with power other 
than as a two-year-old I learned that if you chew on a metal key then 
plug it in, you get a funky burn on your arm that never goes away.

Now, my question is how far does the ether signal travel over the power 
cable?  If this type of thing works as claimed then the ether signal 
must hit the main breaker panel in the house (it has to if it's going 
from one circuit to another) and if it hits that panel does it 
propagate out via the main power circuit to the house then possibly to 
the neighbors houses?  I would imagine that the signal is fairly 
limited in distance but if you've got a 200 amp circuit coming into the 
house that copper has to be of fairly large gauge which would allow the 
signal to travel farther (kind of like 10-base-5 vs 10-base-2 (or 
10-b-t for that matter)).  And if you can blast 14 meg over 15 amp 
wires how far can you shoot a signal down a 200 amp wire?

Any thoughts here?  Could it actually be possible to hack a neighbor 
(or at least sniff) over the power lines in the 'hood?

I'm sure this is providing someone with a good laugh, but like I said, 
I'm not EE.

Greg