[Amps] 10dB and propagation

[Bill Fuqua]

         In the late sixties and early seventies an EE  professor of mine 
was doing research into plasma physics studying the effects of ionization 
on radio propagation. The study had to do with studying the nonlinearity of 
plasmas which causes a high degree of signal scrambling (intermodulation, 
cross-modulation and harmonic generation) when the plasma density is high 
(such as you would have after a nuclear atmospheric blast). There were 
concerns about communication and radar operations in such 
environments.  There was just only so much he could do in the plasma 
physics lab inside the long glass tubes with water cooled magnets around 
them and KW RF generators.
        He propose that the university allow him to build a large 
transmitter  and antenna system (cloud warmer) to produce ionization of the 
upper atmosphere and then probe it with other radio signals to characterize 
the non-linearity of the signal path.
The altitude of the zone of plasma that would be produced was related to 
the frequency of the high power signal. This was related to mean distance 
between the atoms in that region. Also, the probe frequencies were not 
chosen as those that would be most refracted or reflected which is related 
to the electron density (plasma resonance).  The idea was not to optimize 
the return signal but to determine what would happen to signals that tried 
to pass thru the plasma (some very small amount would be returned).
         The department chairman pulled the funds so that he could have the 
front office remodeled and others got to do this work.

73
Bill wa4lav




At 06:45 PM 2/7/2005 +0000, David G4FTC wrote:
>W2DTC wrote:
>
>
>>Did you ever notice that when the Navy or Air Force wants to buy a new 
>>ship or airplane, that there are congressional meetings and many hurdles 
>>to overcome to get the funding?  Does it then strike anyone as odd that 
>>the military would get funding for a Statement of Work that required 360 
>>ten thousand watt transmitters and 180 large antennas that would radiate 
>>a signal that is tens of thousands of times less than the Sun's natural 
>>electromagnetic radiation?
>
>
>See my previous posting.
>
>HAARP was orginally conceived to generate ELF signals - if I recall 
>correctly for communications with
>submarines while submerged.
>
>Prior to HAARP there was a project to install an ELF antenna across the 
>state of Wisconsin (project Sangine) - but public outcry put pay to that.
>HAARP and the other Ionospheric heaters work by acting upon the polar 
>electrojet and it only requires a relatively small amount of power (but in 
>the MW range) to effectively modulate the electrojet.
>
>Compared to the cost of an aircraft carrier or aircraft - HAARP is cheap! 
>Probably paid for out of petty cash.
>
>Regards
>
>David G4FTC
>
>
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