[Amps] 10dB and propagation
David G4FTC
g4ftc at hotmail.com
Mon Feb 7 12:29:29 EST 2005
>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 Luxembourgs 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 mans 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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