[TriLUG] Powerline - Ethernet over AC lines & Linux
Neil L. Little
nllittle at embarqmail.com
Fri Sep 21 23:25:06 EDT 2007
Yes I will allow that the idea of BPL does have its merits. However, at
this time except for the two examples
of BPL technlogies that have managed to operate within the part 95
incidental emitter limits (use of MV
residential lines and not HV feeders) none have proven the ability to
operate such a system without causing
an racket in services that use the radio bands in question.
One of these systems was Motorolla's Home Plug product that used MV
lines. Alas Motorolla set a side this
technology as it required far too intensive amount of maintenance and
was not an economically viable product in
Currently the only Power company using BPL that has never received any
complaints is in Cincinnati (Cinergy).
This system uses a MV powerline technology which has been proven not to
incure incidental radiation levels
in excess of part 95 limits.
Britain also tried out BPL (They use the term PLT) and finally
determined it was basically unworkable and thus
abandoned the technology. The EU has also written off PLT.
Just recently NATO published a report that cited:
A high probability that PLT would cause increased noise levels at
sensitive receiver sites given the projected
market penetration; and the percentages are highly influenced by
assumptions on transmitter EIRP (equivalent,
or effective, isotropic radiated power), PLT market penetration and duty
Now the city of Raleigh is implementing water meter reading using an RF
signal. Progress Energy is also using a similar
scheme and all are of course well within part 95 limits. I have never
encountered any interference problems with any
of the radio bands I am licensed for.
The issue with BPL in the US has been that Power Companies with obvious
interference issues from BPL have not
responded to the complaints. Because of certain political ideologies
involving the current administration and the
FCC's strange lack of appropriate response to demonstrative evidence
from independent and unimpeachable sources
have left a bad taste in the mouth of those having to deal with the
interference issues (yeah, I lifted that phrase from
another ARRL article).
Around these parts Progress Energy did have a BPL trial in the Raleigh
area. The interference resulting from that trial
severely impacted the services using those radio bands. The good thing
is that Progress Energy saw the error of their
ways and terminated their trial. Progress Energy currently have no plans
to implement a BPL system (Also right after
this trial Progress Energy sold off their ISP holdings).
Neil Little, WA4AZL
Ron Joffe wrote:
> On Friday 21 September 2007 21:39, Neil L. Little wrote:
>> Of course there is
>> more to the story but basically BPL is a bad idea.
> Sorry to be the dissenting view here, but it's not as much that BPL is a bad
> idea, but that there have been some bad implementations. If you were a rural
> farmer and wanted something faster then dial up, in many parts of the country
> you don't have much choice. If your local electric utility comes and offers
> you a choice, at what cost would you take it?
> Powerline carrier in itself works quite well, Many utility have (or are in the
> process of) implementing powerline carriers to read their electric meters.
> That's a situation where the technology is there, it does not interfere, and
> provides a very good solution. The situation comes when you try to increase
> the bandwidth to the point where the electric lines start radiating a
> significant amount, then you get nice radio spectrum interference.
> The power levels are a direct result of cost to benefit ratios. Some system
> utilize rather low power, and many repeaters to achieve a BPL solution which
> does not interfere. Repeaters are expensive to install and maintain. So there
> are clean solutions, but at a higher cost. Finally it comes down to what the
> farmer in the rural area is willing (and able) to bear to catch up to the
> rest of us.
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