> pretty big storm front about half way between us at the time. I just
> can't
> explain the delay in the signal. It was about half a morse character (or
> less) at 25-30 wpm. That would make the delay about half a second.
> Maybe
> my ears were off and the delay was say 100 mSec. That would make the
> distance 186000*.1 = 18,600 miles. That is very close to the
> circumference
> of the earth. WOW! ..
I only know a little it about this, but one thing that jumps out is assuming
the velocity of propagation through the ionosphere and atmosphere is unity,
or the speed of light. If we assume radio waves travel as if in vacuum, the
time delay seems unexplainable.
EM waves propagating through water or through a plasma (or even air) are
certainly slowed. The amount of slowing depends on the permittivity and
magnetic inductive capacity of the media.
Also, there are other modes through a plasma (the ionosphere is a plasma)
than the normal EM wave propagation we expect. Slow-wave propagation through
a plasma is pretty well known when working with plasmas, and I expect it
occurs in the ionosphere also.
I think there is a collision mode also, where the wave propagates very
slowly via collisions between ions. Don't quote me on this though. :-)
There is another effect that causes long delayed echoes. I knew a kid in
high school who used to record and play back, at very low power into a dummy
load, transmissions by his neighbor. He would be in his basement working on
a project, walk over to his radio and push a button on his reel to reel tape
recorder, and play back a delayed copy of his neighbor's transmissions.
Somehow he had the reel to reel rigged to make a delay, probably an
additional playback head downstream of the record head.
The neighbor was so loud the kid could receive his neighbor over top of his
own transmitter (because he transmitted into a dummy load and received on an
outdoor antenna). His neighbor would go on and on at club meetings about the
echoes he heard, and how his signal must have been bouncing off the moon and
how sometimes it had a strange frequency shift to it.
I always wonder, 45 years later, if that person has grown up and is still
active....but with a voice fancy recorder system.
73 Tom
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