[Amps] 10dB and propagation

["David G4FTC" <g4ftc@hotmail.com>]

> I don't believe there is ANY transmitter on earth (amateur or pro)
> that could influence the ionosphere by causing a non-linear behavior
> in that.

No one seems to have mentioned the Luxembourg Effect.  This resulted in 
Radio Luxembourg?s signal appearing on other nearby signals through 
ionospheric cross-modulation.

In the past there have been a number of well publicised experiments using 
ionospheric heaters in an attempt to partially control (or more correctly 
modify) the characteristics of the ionosphere. Some of these experiments may 
still be on-going.

The power emitted by these ionospheric heaters is QRO in terms of man-made 
radiated power but is only a fraction of the energy which the ionosphere 
receives from the Sun. The key seems to be using the right frequency from 
the right location ? and most ionospheric heaters seem to exploit the 
properties of that part of the ionosphere which contains the polar 
electrojet (E layer?), which under the correct conditions, can be apparently 
controlled/modified with relatively small amounts of incident energy.

In 1996 the BBC made a ?Horizon? programme called ?Masters of the 
Ionosphere? which outlines the history of man?s attempts to control the 
properties of the ionosphere, sometimes with quite amazing results. For 
anyone interested in some of the more unusual aspects of radio propagation, 
this programme is highly recommended. Transcripts of the script are 
available for download from a number of Internet sites ? a google search on 
?Masters of the Ionosphere? will give locations, but the video really is 
worthwhile viewing as it contains many graphics which really help to 
illustrate the underlying principles involved.


David G4FTC


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