On Mon, 10 Jan 2005 23:30:42 GMT, "U Know Who"
wrote:


"itoldyouiamnotiamnotgeorge"
wrote in message ...
Dave Hall wrote in
:

He's right, Dave. You can receive more than one skip signal from the
same transmission, and their phasing can cause intermodulation
distortion in any RF stage of your receiver.

No dice Frank. The effect you have described is commonly referred to
as "multipath". The differences in phase angles of the received
signals can cause either an addition to or a subtraction from the
fundamental signal. But it does not cause it to splatter. A special
form of this is called "selective fading" which can cause different
parts of the signal to fade differently, which can distort the audio.
But this is not "splatter, and will not make the signal "bleed" more.
Heck the HF ham bands are almost always utilizing skywave propagation.
If what you say were true, then the ham bands would be virtually
unusable due to all the signals splattering across the band. With the
exception of a few bad apples running some illegal equipment, this is
normally not a problem.

All that's required is
enough non-linearity in just one stage and the signals will modulate
each other.

I have never seen this happen in any of the quality receivers I've
owned over the years.

Unless the signal is in motion (doppler effect) the frequency will
remain the same even if the phase shifts. Since all the multipath
signal frequencies are the same, there will be no mixing products
generated.

If that were the case, then any group of signals, local or skip, would
do the same thing. That's not something that you'd want in a good
receiver. But you can't pin the faults of a bad receiver design on
atmospheric phenomenon.

This is almost as hokey as saying that a certain antenna will make you
sound "louder".

Propagation, like antennas, are passive. It only radiates or
re-radiates a signal. It does not modify it . If a signal is clean,
then the propagation will propagate it as such.

The result is what appears to be splatter but is really a
fault of the receiver. Happens all the time with cheap shortwave
radios.

Ah! But why do you assume that I have a "cheap shortwave radio"?

What happens when you put a low noise GasFET preamp behind a bandpass
filter and then into a spectrum analyzer? Surely you know what
splatter looks like on a spectral display?

And DX doesn't have to be up to get a good signal -- I have
heard many clear DX signals from seemingly dead bands.

A clear, and stable DX condition will not distort a radio signal.

A station which is backswinging wildly, with fuzzy distorted audio,
and splattering 3 channels in each direction, is running illegally,
regardless of the fact that the FCC hasn't yet cited them for it.

Yeah. So what? But was I LOUD?

You were 10-8 and straight across my duck pluckin' end that's for
cotton picken real. ;-)

Dave
"Sandbagger"