[RFI] Broadband over Power Line (BPL) radio interference

Dave Bernstein aa6yq at ambersoft.com
Thu Jul 15 14:50:07 EDT 2004

Attacking BPL on the primary grounds that it causes severe radio
interference to hams, CBers, and SWLs is a bad idea. Why? Because too
much of the audience will wonder why we should hold back the advance of
broadband internet access so that a small group of retro hobbyists can
continue to communicate via the ionospheric refraction of HF signals.

Consider the following hypothetical situation: A research group develops
a medical instrument that destroys every cancer cell without damage to
normal cells. As a side effect, this instrument generates enormous RFI
in the 3.5 mhz to 28 mhz range; the instrument's effectiveness depends
on the use of precisely this frequency range. Would we take the position
that this  device cannot be deployed because it would prevent amateur
operations within, say, a 50 mile radius of any hospital? I think not.
We'd be unhappy, but none of us would deny the world a cancer cure to
preserve HF amateur radio.

The above situation is hypothetical -- no such instrument exists -- but
illustrates that there are advances for which even we hams would accept
the demise of our hobby. Cheap rural broadband access isn't a cure for
cancer, but there are a lot of people with little knowledge of or
sympathy for amateur radio. To them, our anti-BPL arguments look way too
much like old fogies holding back the wheels of progress. Though their
execution was rather clumsy, we've already seen the UPLC painting this

Fortunately, there's a more effective way to attack BPL -- its economics
are terrible. There are two reasons for this:

1. its not "plug and play" -- transformers must be bridged, or
pole-mounted WiFi transceivers must be installed to provide connectivity
to subscribers; the resultant labor costs and time-to-revenue delays are

2. it generates electromagnetic interference to a range of critical
public safety and aviation services, the mitigation of which can
introduce unpredictable delays in deployment (and thus revenue) as well
as signficant (and not yet bounded) costs

Even more fortunately, there's a better alternative to BPL -- WiMAX. The
advantages of WiMAX have already been enumerated on this reflector, so I
won't repeat them here. However, I will note the lack of engagement with
our most effective allies in this fight: the companies driving the WiMAX
consortium. Intel is building its strategy around WiMAX. There are
another 100 companies -- AT&T, BT, Covad, France Telecom, Fujitsu,
Motorola, Proxim, Qwest, Siemens, Tata -- serious companies committed to
driving WiMAX down the same ubiquity curve we've enjoyed with WiFi; see
http://www.wimaxforum.org/home .

As an example, what would be the impact of the WiMAX Forum and ARRL
jointly announcing that amateur radio operators will make tower space
available to WiMAX operators at no charge? I'd certainly forgo the
monthly rental fees to help preserve HF amateur radio.


        Dave, AA6YQ
        (not affiliated with any telecom company)

-----Original Message-----
From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
Behalf Of Rick Karlquist
Sent: Thursday, July 15, 2004 13:19
To: larry at dailynewsgroup.com
Cc: rfi at contesting.com
Subject: [RFI] Broadband over Power Line (BPL) radio interference

To:  Larry Magid
     Palo Alto Daily News

In your recent glowing report (Palo Alto Daily News, July 15) about BPL
in Menlo Park, you completely omitted the fact that BPL causes severe
radio interference to radio frequencies up to 80 MHz.  These frequencies
are used by amateur radio, citizen's band (CB) radio, shortwave
broadcasting, the CHP, and TV channels 2 through 5, as well as many
other radio users such as ships and airplanes.  BPL has been tried in
other countries such as Austria and Japan and has been abandoned because
of radio interference problems.  The BPL signals that are supposedly
transported on the power lines actually radiate using the lines as
unintentional antennas. Shortwave radio signals travel very long
distances, so the interference is not confined to the immediate vicinity
of the BPL system.

The BPL enthusiasts have tried to duck this issue by alternately
claiming that BPL doesn't cause interference (it most definitely does),
or they have fixes for the interference (yet to be demonstrated), or
that it's OK for them to interfere because shortwave radio is
federal law, it is illegal for an unlicensed technology such as BPL to
cause harmful interference to licensed radio services.  Michael Powell
and others at the FCC are in denial about this and refuse to enforce
FCC's regulations that are an inconvenience to Powell's broadband

Richard Karlquist
Cupertino, CA

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