[evlatests] More on S-band birdies ...

[Rick Perley]

    In looking at the autocorrelation spectra, we find the peculiar RFI 
at S-band is more peculiar than previous reported:

    The separation between the birdies is 128 MHz, not 256MHz.  They are 
all 'centered' at 3200 MHz.  Different antennas show different RFI 
lines, but all of them are n*128 MHz away from 3200 MHz. 

    In this experiment, subband 6 contains 3200 MHz in channel 577.  
(Because the subband separation is 128 MHz, all birdies are in channel 
577 of the relevant subbands). 

    Antenna 8 shows them strongly in subbands 4, 6 and 8, and weakly in 
subband 7
    Antenna 9 has a very strong signal in subband 5, and none in any other!
    Antenna 15 shows them weakly in subband 6 and 8.
    Antenna 24 has it only in subband 6.
    Antenna 27 shows them weakly in subbands 6 and 8.
    Antenna 28 shows it strongly in subbands 4 and 8. 

    An explanation is wanting ...