Why do you assert that government users are not concerned? They are very
concerned, do studies, publish papers, and hold conferences. However, public
safety and defense concerns are not usually for public consumption. My
government contacts who conduct field studies tell me that even NATO is
concerned, the problem being that the aggregate transmitting power on miles of
radiating lines is enough to be detectable after ionospheric bounce. We're
talking very large distances.
By any measure, BPL/PLC in the HF band is dung. BPL was conceived by
businessmen who don't know coax from garden hose, implemented politically on
the business side and by engineers they pay but don't listen to on the
technical side. Among other critical services in the HF band there are long
distance aircraft and maritime communications, research telemetry, and all
sorts of other things that depend on reliable reception of weak signals.
These are scattered all through the HF band, and notching the hams is
politically expedient but no protection for these other users. Believe me,
the FCC is in the loop on this, but Michael Powell rammed approval down the
throats of staff. He's a lawyer, and science be damned.
Now shut up about the hams. They have sound science behind them and the
technical problems cannot be finessed away. You do understand, I hope, that
notching means in-band energy reduction, but not elimination. It helps but is
not a panacea by any stretch of the imagination. And yes, the hams are well
regarded for their ability to provide emergency communications. The amateur
service is predicated on such capability along with advancement of the
technical art, and not simply as an indulgence for hobbyists.
Orin Laney
On Tue, 18 May 2010 15:59:43 -0500 Mark Gandler <[email protected]>
writes:
Unfortunately, hams complaining about anything and everything related
to BPL,
even small home Ethernet adapters, which are notched, signals are lower power
and they get significantly reduced power beyond any circuit breaker. And those
products are easier targets, as there are more of them around, they are on
store shelves and fall under EMC Directive.
and why are the majority of the complaints come from UK? BPL has much
higher
sales in Germany and France.
As well we are not getting any complaints from any government
operations.
If hams will be the only ones with communication devices left during the
disaster, please make sure to post your addresses, so we can all flock to it,
I am not joking.
________________________________
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To: [email protected]; -
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