Airy R. Bean wrote:

Even so, would not the modulation characteristic be known, and therefore
a noise blanker developable, very much the way that Radio Hams do things?



I'm not sure that it would possible Gareth to the extent needed.
The problem is that local noise depends on the activity of local PLC
modems, each of which is going to produce an additive but independent QRM.
You wouldn't know beforehand when data was going to be requested or sent.
It just sounds like random data bursts spread over a wide spectrum.
Yes, some suppression might be possible by taking a wide bandwidth and
somehow using cancellation. But getting 40dB or more of rejection I
think would be very difficult.

The galling thing about PLC/BPL is that the vested interests (i.e. the
power companies) seem to think that they can ignore all other spectrum
users. Yet the bandwidth they're offering will soon be insufficient
to meet the broadband demands. At least with ADSL line bandwidth can be
shared among a small number of subscribers. Greater bandwidth can be
achieved by reducing that contention ratio. But I wonder how many houses
are served by the same power substation on average. IMO, PLC/BPL is
the wrong technology too late. Even ADSL is going to struggle to meet
the bandwidth for on-demand video streaming.

As a final irony, now that the ITU has dropped mandatory CW, CW with
its much lower bandwidth offers the best chance in the presence of
such wide spectrum noise. Looks like my pursuit of CW as a mode was
worth it after all ;-)

David, M0DHO