[Amps] article in Nature, modified Aurora via HF

G3rzp@aol.com G3rzp at aol.com
Tue Apr 19 03:56:37 EDT 2005


 
In a message dated 19/04/2005 06:14:54 GMT Standard Time,  
G3SEK at 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



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