John Smith I wrote in
:

Dave Oldridge wrote:
John Smith I wrote in
:

Dave Oldridge wrote:
John Smith I wrote in news:fa4i2a$jve$1
@news.albasani.net:

Dave Oldridge wrote:

...
You need a good book on digital error correction algorithms in
digital communications.

Unless you have constructed a real rf jammer (white noise really),
BPL will eat up any legitimate amateur communications you can
throw at it ... however, rumors do prevail, like the one about the
tin foil hat.
So how is it gonna eat up having its receiver saturated? I'm pretty
familiar with digital comms and, with the exception of some pretty
slow speed stuff designed for weak signal work, most of it is not
very good unless you have a really solid signal-to-noise ratio.
I'm just saying that if it's getting out to my antenna that loud,
then my kilowatt is gonna have a fair chance at saturating the
thing's receiver. And the more noise they make, the more I'm apt
to have to use the kilowatt to shout over them.

Of course in our current enforcement situation here, I'd probably
simply be told to stand down and have to go to great legal lengths
to appeal the ruling.

Digital is not analog, when adverse conditions have made an analog
signal totally unusable, a digital signal, most likely, may still be
achieving 100% error free data transfer--it is just the nature of
the beast.

Actually, I've found that, except for very slow data rate stuff,
digital signals require a BETTER signal-to-noise than analog to be
readable. And there is no partial readability with most of the
commercially-used digital modes. That is to say you either have
error-free transmission or none whatever.

The "intelligence" of the software controlling the data
transmission(s) is the single most important factor--as logic would
dictate. Even under almost total saturation (it would be virtually
impossible for 100% saturation, baring hooking the kw+ rig directly
to the power lines) of the BPL signal some type of heterodyne would
be occurring with the KW signal. Since digital is simply detecting
an ON/OFF signal, in conjunction with spacing/length of these, an
on/off signal is still detectable in this heterodyne--given the
software is aware and capable of reading this signal and switching
"modes" to do so, no harm is done to the data ... and without doubt,
new error correction methods will also develop as BPL grows and
hf-rf-terrorist-hams challenge this system ... LOL!

You cannot recover data with a modem whose input transistor is biased
off by rectified RF. I know this. I've tried it.

Digital is magnitudes more robust than analog, again owing to the
very nature of the beast and the simplicity of the on/off, pulse
width, timing nature of the signal.

The only real advantage digital has is its error-correction
algorithms. Those can do very good work when they actually have
enough data to work with. But once the data recovery by the the very
ANALOG device that is receiving the signals drops below their
threshold, then the recovery becomes terrible. Some modems are
better than others. My old Telebit 19.2K could suck 1200 baud
recovery out of a phone line you couldn't talk on. But give it a
couple of volts of RF in the mix and it would drop stone cold dead.
And BPL has the "disadvantage" of not being able to filter our
frequencies AND use them at the same time. At worst, I'd drive the
BPL machinery to other parts of the band from where I was working....



Obviously, we have NOT seen the same equip/software/algorithms and
successes ... dream on ...

Algorithms will only help you by slowing down and using redundancy or by
being frequency agile and thereby clearng off my frequency. And NO
equipment DESIGNED to be a sensitive receiver at the frequencies you want
to use will be immune to even stronger signals picked up by the open
ANTENNA that you're using for a "transmission cable."

Dream on.

Look, I don't want to tell you how to engineer. But you've obviously got
your mind made up and the facts and experience of others be damned.


--
Dave Oldridge+
ICQ 1800667