Propagation... why do I miss some signals?
It's easy to 'mix' theories, here... one reason I posted these was to provoke discussion!  I'm not sure anyone knows Exactly what happens here... but my limited research and background has led to these thoughts... let me fumble my way through them... Sad
Assume Vertically polarized EM signal, wave (planar) explanation:
[Image: RFwave.jpg]
One cannot exist without the other. They are in phase, one supports and produces the other. An EM wave can be produced either with a changing Voltage Signal, or a changing Current. Whichever, it will cause the creation of it's "partner".  The H signal plane (magnetic field) energy, exists at right angles to the E plane (energy field)

An antenna must be of construction type,  physical length, and mount orientation to receive the the specific field 'plane'.
EM travels inside the Earth Ionosphere wave guide, as surface (subsurface also if ELF), space, or skywaves. and in a vacuum propagate at the speed of light. They are created by man, or by nature.

The impulses we are interested in are produced by nature, through sudden changes in the electrical charge environment of the atmosphere, (charge, discharge, steady state) caused by build up or decrease in charges, such as protons, electrons, ions, what-have-you.  A discharge, cascade, etc. can be triggered, for example, by a cosmic wave, change in earth''s magnetic field... jet plane, meteor,.... etc....or exceeding the 'voltage breakdown' potential of the 'envelope' that contains the charge.

The H field loops  detect the magnetic portion of this 'EM impulse' wave.  If strong enough, it will also detect some of the E wave components.  for our purposes, we use a long wire constructed in a loop.... if it were a true wavelength long, for an impulse with energy centered at 15 kHz  would be about 20,000 meters in length (20 Km or 12.4 Mi).... Our loops don't have to be that long, because of some  funky characteristics of EM signals, and fancy mathematics... heh...

An E probe of 150mm length would be fantastic for detecting the Vertical E field signal in the 2 GHz band... but iis much too 'short' for an E 'wave field' at 3-300 Khz... unless the field was very intense... It is virtually immune to H(magnetic) influences since it is NOT a coil. ... sure, it will 'feel' E 'plane' 2GHz RF, but our systems cut off at around 300 KHz..

Instead, the probe surface area mimics the CHARGE content, and changes in the environment around itself at any given instant.  In effect, a 'capacitor' plate.    this charge  in the virtual capacitor between the probe and earth is impedance matched to the receiver's amplifier chain. The Common plate for the virtual EA capacitor, and the E probe capacitor is Earth.

This charge field is NOT an EM wave field.  It will produce an EM field of whatever polarity and strength is proportional to that total charge, and its strength,   depending on the amount and speed of the content change. It is the progenitor of, not an artifact of, the EM impulse wave.

A person might say that the EM impulse we detect with a loop is therefore initialized  by the atmospheric content changes of the required intensity, at that location and in that environment, and its E plane partner rides along with it.

The E probe monitors and reflects that atmosphere content instantaneously as it is 'felt' at the probe. Whereas an EM receiver must 'wait' until the change is strong enough to create a 'wave front'. ... so the E probe signal in theory should be just a tiny bit 'faster' on a display device for example, and considerably 'faster' depending on the number of reflections the EM might make from a distant impulse.

If you should take a passive CB or similar vertical antenna, disconnect it from the receiver, and connect a volt meter across the connector, you can watch the 'field' value change as a storm cloud passes overhead.

Note that the EA capacitor charge content DOES NOT reflect off the Earth Ionosphere Wave guide, as an EM wave does.  It is felt WITHIN that capacitor formed by Earth Atmosphere in it's entirety, as fast as the 'charges' can propagate. Since it doesn't reflect, it has a 'shorter' path to a more distant receiver. And theoretically could be detected by all... no "skip"....  Unfortunately, this can't occur in our reality...the actual propagation is affected,  e.g.  more intense local field changes near any specific receiver obscure, variable changes in the air dielectric, etc....

So, if the above is some 'rough' thinking, as a 'starting point'..... we can evolve a real hypothesis that explains everything,  publish a paper, win a Nobel Prize, and become rich and famous...
Have at it....

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RE: Propagation... why do I miss some signals? - by cutty - 2018-10-22, 13:27

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