Hi Chris

73 Eddie G3ZJO

On 07/04/2011 17:45, Chris Trayner wrote:

On 7 Apr 2011, at 17:24, qrss wrote:

  Considering they
originate from a 50Hz source they are strongest at lower frequencies,
rarely climbing above 6kHz but peaks sometimes get to 8.971kHz not much
higher..

Yes, but they disappear between 8970.03 Hz and 9876.57 Hz - that's a very small 
band for anything to knock them out. It's 0.00105 of an octave. If something is 
acting like a low-pass filter, at 6dB/octave/order, it'd have to be something 
like a 500th order filter to drop the signal by 3dB.

I agree, it does look strange.


73,
Chris G4OKW

-----------------------
Dr Chris Trayner
School of Electronic&  Electrical Engineering,
The University of Leeds,
Leeds LS2 9JT, United Kingdom
Tel: +44 113 34 32053
Fax: +44 113 34 32032





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