In a message dated 19/04/2005 06:14:54 GMT Standard Time,
G3SEK@ifwtech.co.uk writes:
But how many reports of the "Luxembourg effect" over the decades have
been due to cross-modulation in receivers? We skeptics need to know.
The Luxembourg Effect was first noted in the 1930s when Radio Luxembourg
started up with what was, for then, high power - I believe it was 250kW on
medium waves - i.e. the 550 - 1550kc/s (as it was then!) broadcast band. Cross
modulation from it onto other B/C signals was then well documented by many
observers, and of course, the first thoughts were that the problems were caused
by
receiver deficiences. Apparently one of the points that led to this being
discounted was that Luxembourg' signal would fade down but on another
co-located
receiver, the CM on another channel would get worse. As I remember reading
about it (I wasn't born until years later!), it happened during the
ionospheric tilting as darkness came on and the D layer ionisation changed.
Since IM and CM are both caused by non linearity, I've no doubt you can get
IM from the ionosphere. What I do doubt is that even at Rich's power levels,
it's noticeable, while I have severe doubts about his measurement technique.
73
Peter G3RZP
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|