Jim Nye wrote:

On Tue, 19 Aug 2003 14:02:48 GMT, Doug Smith W9WI wrote:

Jim Nye wrote:

Unfortunately, the technically unsophisticated do not recognize the
difference between coherent and non-coherent noise, and this makes it
easy for the ARRL to spread its FUD. But the fact is that, if BPL
signals are heard at all, they are coherent (have a predictable phase
and amplitude) and therefore can be completely removed at the
receiver. This can be done in many ways, most of which amount to
nulling the BPL signals by introducing an identical signal which is
180 degrees out of phase with the original. As a matter of fact, most
current HF transceivers have what they call a "noise reduction" option
already built into them which uses the nulling method to accomplish
its goal.

?? I'm not aware of ANY HF transceivers that contain nulling-type noise
reduction circuitry. (and as an active contester with 30 years in ham
radio, I'm aware of pretty much every transceiver available)

Many transceivers do include a "noise blanker". This works by detecting


The Icom 746PRO contains such a circuit, which is separate from its
noise blanker function. Basically, the 746 samples slightly out of
band signals in order to determine the probable phase and amplitude
of coherent interference, and then it subtracts them from the in-band
signals. I believe that several of the Yaesu FT series transceivers
can do the same thing.

In any case, that's not the primary point of the post. The point is
that the ARRL has conveniently neglected the coherency property of BPL
leakage signals.



If the signal has predictable phase and amplitude, then it conveys no
information whatsoever. Otherwise I'd want an internet experience that
could predict what I want to download an do it for me. If it really
worked it could predict the content and create it on my machine. My
internet connection would be truly virtual.

Wow!

I don't think so.


craigm