On Wed, 28 Apr 2004 10:29:00 -0700, Marlon Schafer (509-982-2181)
wrote:
>Great points!
>
>So is there a way for the wisps and the Hams to help the BPL community build
>a better mousetrap?
Sure.
The better mousetrap is to use other parts of the spectrum where the
interference issues can be far more readily controlled. This is a big
part of why RF engineers think BPL is such a lousy idea -- there are
far better ways to do it (far less interference, far less complication,
more cost effective). When I travel out west, I see "last mile" systems
that are distributed via UHF from mountaintops. Subscribe costs are
equivalent to what I pay for cable modem service in my Chicago
residential neighborhood (where I have two cable systems and DSL as
competition). There are several proposals before the FCC re: sharing of
additional frequencies that are used for satellite uplinks.
Interference in these other parts of the spectrum is very easily
controlled by the use of directional antennas (like the dishes used for
Direct TV), and the radio waves are limited by line of sight (so no
interference halfway around the world).
If you study the NTIA report (see link from someone posted earlier
today), you will see that deployers of BPL systems will have to jump
through some serious hoops to avoid interference, and all of these
"hoops" cost lots of money (lots of engineering time, lots of
variability of system configuration, lots of attention to the details
of the installation and the maintenance of the power lines). And the
BPL proponents asked that Part 15 rules (the FCC rules that prevent
interference) to be relaxed. The NTIA report says these rules should
definitely not be relaxed, but should be made significantly more
stringent! In other words, they are essentially agreeing with the ARRL
positions without mentioning ARRL.
Jim Brown K9YC
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