Astro wrote in message news:opshy5fcl1v1dc2q@athlon2600...
When you run high frequencies through any wires, you'll get radiation. I
suspect the frequencies used for BPL (mhz), combined with the waveforms
used, will lead to radiation at a variety of frequencies due to the
harmonics.

Not really. Depends on their efficiency as an antenna. Consider
coax. Cat-5 (UTP) is rendered a lousy antenna by the pairwise
twisting. Cogitate as follows:
Say a pair is carrying waveform, and length per full twist is l. l is
much shorter than wavelength on cable. A section of cable of length
l/2 propagates electromagnetic radiation to cancel that of adjacent
l/4-length sections.

Not to mention the very low-voltage (fractional volt) signal and hign
forward impedance.

HTH,
John

Sorry, of course you're correct, thanks for clarifying.

I should have said "any power wires", since power lines are not shielded
or run in twisted pairs. The HAM radio folks say that the emissions from
power wires containing BPL transmissions can be detected up to a mile away.


On 24 Nov 2004 13:39:04 -0800, John Barry wrote:

Astro wrote in message
news:opshy5fcl1v1dc2q@athlon2600...
When you run high frequencies through any wires, you'll get radiation. I
suspect the frequencies used for BPL (mhz), combined with the waveforms
used, will lead to radiation at a variety of frequencies due to the
harmonics.

Not really. Depends on their efficiency as an antenna. Consider
coax. Cat-5 (UTP) is rendered a lousy antenna by the pairwise
twisting. Cogitate as follows:
Say a pair is carrying waveform, and length per full twist is l. l is
much shorter than wavelength on cable. A section of cable of length
l/2 propagates electromagnetic radiation to cancel that of adjacent
l/4-length sections.

Not to mention the very low-voltage (fractional volt) signal and hign
forward impedance.

HTH,
John

berkshire bill posted for all of us....


"G. Morgan" wrote in message
...
On Mon, 22 Nov 2004 17:25:24 -0500 "MC"
used 21 lines of text to write in newsgroup: alt.home.repair

One day may have only one wire to plug up, will be power and high speed
network modulated over the same power wire also !

It's called BBoPL and it's here already. The HAM radio operators are
furious about the FCC approving it's use.


--
-Graham

Remove the 'snails' from my email

Why are HAM operators concerned over wired transmissions ?

Bill

Because the wire in the power line acts like an antenna and radiates
spurious signals over a very wide range of frequencies jamming them.
--
Tekkie

Why are HAM operators concerned over wired transmissions ?


You can read about it he
http://www.arrl.org/tis/info/HTML/plc/index.html

I knew of the deployment of signals, but didn't think through the impact or
it's seriousness.

Happy modeming,
Bill