[evlatests] '8797 Birdie'

[Rick Perley]

    A number of tests have been done to elucidate the nature of this 
birdie.  It's defnitely a weird one!

    All test are in spectral line.  I give below the *center* frequency, 
full BW, and apparently
frequency of the birdie. 

A)  8790/25 MHz.  The birdie appears at 8797.5 MHz

B)  8793/12.5 MHz.      The birdie is very weak, and appears at 8797.5
      8795/12.5 MHz        The birdie is very strong, at 8797.5.
      8803/12.5 MHz       The birdie is of moderate strength, but at 
8795 MHz. 
       All other frequencies attempted in this run (from 8790, 8793, 
8796, 8806, 8809, and 8812 MHz) showed
no birdies at all. 

C)  8790/6, 8795/6, 8800/6, and 8805/6:  No birdie is seen in any of 
these combinations. 

    Obviously, the 'real' signal is not at any of the frequencies 
listed.  So, where is it, and how is it
getting in?