Topband: Power line communication (PLC) - Trends in Holland

Brad Rehm Brad Rehm" <brehm@texas.net
Thu, 14 Feb 2002 10:25:12 -0600


"...the UK is really up-front in having proposed the so-called N-30
rule..."

"In the shortwave sprectrum the PLC-lines must not radiate a field
more than
about 50uV@50Ohm measured in a distance of 3m to the radiator....
(which is
over S-9  level!)"

"...but the original rule from the EU was a proposal which was more
than 20dB
higher tolerated spurious radiation over the entire spectrum from
1...30Mhz... in that case we can all close down !

Ulli,

Thanks for your observations.  I sensed from the reports I've seen
about the situation in the UK that the EU was willing to tolerate much
higher limits on spurious radiation.  And yes, 50µV at 3m is much too
high.  It's totally unacceptable from the points of view of a lot of
spectrum users.  I would guess that that level was proposed because of
the business opprotunities it affords.

I was also trying to say that we shouldn't despair yet.  Other
spectrum users are going to wade into the fight.  We've also got to
remember that hams have, since the early days of their hobby, been
technological innovators.  Like all the spectrum users, we're going to
have to find technical solutions to congestion, competition, and bad
neighbors.  If we have to operate with PLC noise in the background,
we'll have the advantage of knowing that it's not truly random noise.
There will be ways to deal with it.

Market forces may also affect the outcome here.  Several technologies
are competing to provide these services.  We won't necessary have only
one winner, but I suspect that the PLC has limitations in speed and
bandwidth that are going to put it near the back of the pack.  That
spells death for it in the long run.  PLC lets the power companies and
apartment owners play in the Internet game, but it's probably not
going to let them win.

In the U.S., for example, we're a long way from knowing if DSL is
going to survive in competition with fiber and microwave.  This, even
though it's installed base is much better at the moment than what
we're anticipating for PLC.

73,
Brad, KV5V