Re: another major BPL deployment

[w1rfi@xxxxxxxx]

Dave Houston wrote:

> http://money.cnn.com/services/tickerheadlines/prn/200512190100PR_NEWS_USPR_____NYM051.htm
> http://www.currenttechnologies.com/about/
>
> To preclude further horse corpse desecration by ill-informed hams...
>
> "On April 21, 2005 Ed Hare, W1RFI, Head of the ARRL Labs conducted tests in
> the Hyde Park area of Cincinnati. He conducted these tests on the BPL system
> installed by Current Technologies for Cinergy. ... Ed found that the BPL
> emisions were at least 20 dB below the FCC limits of Part 15 devices across
> the board. He also found that the amateur frequencies have been notched and
> interference from BPL is at least 60 dB below FCC Part 15 rules in all of
> the amateur bands with the exception of 60 meters which was very recently
> added as an amateur band. Ed also noted that there were many other devices
> in the test area which interfered far more severely with the amateur bands
> than the BPL."

The quote you offer came from:

http://www.danielwoodie.com/aboutbpl.htm

I would think that folks may prefer seeing it in its entire context.

The quote isn't exactly correct.  My trip to Cincinnati was a one-day
session in which I met with the local amateurs there and we did some
limited testing.  In the spots we measured, and based on my driving
around, the system there was operating at a level that appeared to be
below the FCC limits.  The design of the BPL manufacturer, Current
Technologies, does indeed notch the ham bands, but nowhere near -60 dB
-- the modems used typically get 25 to 30 dB of notching. From what I
have learned about the Current Technologies systems, the emissions
would more typically be just about at the FCC limits in many
installations. It is likely that a combination of the distances between
my portable test setup and the premise wiring carrying BPL and the
variations in the nature of the premise wiring explain most of the
differences.

In general, at this location, the system was not causing harmful
interference to the Amateur Bands.  The reception of international
shortwave broadcast, governement WWV time signals and similar uses was
degraded appreciably, and as I drove around the general area, there
were areas near active modems where the noise levels were pretty high
outside the notched spectrum. As a separate issue, yes, as in all
areas, there were also areas where other devices were causing noise
levels strong enough to be intereference.  It was my opinion that the
combination of notching and the intermittent nature of BPL operation
there would generally protect mobile operation. This would leave some
potential for interfence to fixed Amateur stations, but with a low
enough incidence of occurrence that it would be practical to deal with
it on a case-by-case basis.

If the point is that in parts of this system that are operating at a
lower level than permitted and that use notching for the ham bands do
not have major interference issues, I would tend to agree. In fact,
this type of deployment formed part of the basis for ARRL's Petition
for Rulemaking to the FCC, asking that the rules be changed to reflect
the more successful BPL installations:

http://www.arrl.org/news/stories/2005/10/18/101/

It is significant that one of the BPL manufacturers that has set out to
avoid major interference problems is among the more successful.  Not
all BPL manufacturers have set out to avoid interference by
specifically protecting spectrum, and those manufacturers that have not
have not enjoyed commercial deployments as large as Cincinnati nor the
pending deployment in Dallas. Others have been embroiled in
interference problems and the associated complaints and costs
associated with them.

So summarizing the concerns of Amateur Radio as "further horse corpse
desecration by ill-informed hams" is not a fair characterization at
all.  In those cases where there has been significant interference, the
characaterization is inaccurate and in cases where Amateur Radio has
recognized improvements in the EMC performance of some designs, the
characterization is a downright mispresentation.

A good summary of this difference can be seen in an editorial written
by ARRL's CEO, Dave Sumner:

http://www.arrl.org/news/features/2005/08/01/1/

Amateur operators are not opposed to BPL -- why should they be? They
are strongly opposed to BPL that pollutes Amateur spectrum, and causes
local harmful interference. Those BPL operators that are willing to
address it when it occurs can expect cooperation and help. Those that
"resolve" it by claiming it doesn't exist can expect firm opposition.

For background in BPL and its impact on spectrum users, see:

http://www.arrl.org/bpl

Ed Hare, W1RFI
ARRL Laboratory Manager
225 Main St
Newington, CT 06013
Tel: 860-594-0318
Internet: W1RFI@xxxxxxxx
Web: http://www.arrl.org/tis
Member: ASC C63 EMC Committee
   Chairman: Subcommittee 5, Immunity
   Chairman: Ad hoc BPL Working Group
Member: IEEE, Standards Association, Electromagnetic Compatibility
Society
Member: IEEE SCC-28 RF Safety
Member: IEEE EMC Society Standards Development Committee
   Chairman, BPL Study Project
Member: Society of Automotive Engineers EMC/EMR Committee
Board of Directors: QRP Amateur Radio Club International