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Old August 20th 07, 11:31 PM posted to rec.radio.amateur.antenna
Dave Oldridge Dave Oldridge is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 234
Default BPL strikes another win ...

John Smith I wrote in
:

Dave Oldridge wrote:

...
Lots of times. My CW error-correcting hardware is excellent, is
always on, and conveniently located in my head.

But you're missing my point. A modem is always an analog device.
And if it's listening on a frequency with a loud signal on it, then
it can be saturated by that signal. I've not seen many that could
copy the heterodyne. Mostly they just stop giving any recovery at
all.


There are very rugged modems. Most people just accept the modem which
was included with their computer. A cheap modem implemented, almost
totally, in software; these can exhibit poor performance.

You get what you pay for, and like I say, BPL is a developing
technology; or, in other words, problems must be found before they can
be fixed. Your KW+ signal will be a great aid, possibly, in that
direction ...

Having worked in the software/algorithm/data-compression aspects of
modems, I have experienced high levels of line noise on standard
modems which needed new techniques to solve ... Although I have seen
many instances where line noise is at such levels even speech is
horrible, and data xmission slows to a crawl, there are few instances
where it becomes absolute zero--baring the physical disconnection of
the line.

If you are inducing interference of a noticeable level in a persons
home/business that is noticeable, it will be more than just noticeable
on the BPL modem!


Not so. Most home and business equipment is not DESIGNED to receive
signals on frequencies where I operate (the single exception being some
cable systems that use the 2m band). Nor is it using wiring that is WIDE
OPEN to my signals. In fact the worst offenders are stereo systems with
parallel speaker leads that need only a bit twisted pair, bypassing and a
ferrite or two to eliminate all the pickup. Shielded wires may also need
toroids to eliminate magnetic pickup that goes right through the shields.

But sending an HF signal down an open power line is not just inviting
interference, it's BEGGING for it, since you've given the system a very
large antenna and put a sensitive receiver on the end of it.
DELIBERATELY. That's like designing a gun with a plugged barrel and then
firing it!

--
Dave Oldridge+
ICQ 1800667