[evlatests] Oscillatory Gain in ea09

[Rick Perley]

     A very fast gain variation is present in ea09, on the LCP side 
only, in one IF only, apparently in all frequency bands.

     The period is very short -- 0.5 seconds -- which likely explains 
why it has not been seen before.  (The ACU tests have revealed it).

     The behavior has been present for some weeks, at least.

     The IF channel is appears in is not the same at all bands.  From my 
four-band tests of yesterday, I see it in:

     *  IF 'D' at C, X, and Ku bands
     *  IF 'B' at L band.

     I attach a plot to illustrate the problem.   The data are from C 
band.  The four panels show the normalized *voltage* gain for ea09, at 
A, C, B, D IFs (from top to bottom).  The oscillatory behavior is quite 
obvious.   The amplitude is about 10%.  There is no phase effect.  The 
sample time is 0.1 seconds.
     No other antenna/IF does this.

     Certainly a 'digital-thingy'.  Can somebody diagnose and correct?


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