[evlatests] RFI retraction

[Rick Perley]

    My note yesterday about the high RFI powers at C band should be 
disregarded.  I was looking at cross-power spectra, rather than 
autocorrelation spectra.  The former are relevant when comparing the RFI 
to external sources, the latter are relevant when assessing the effect 
on samplers. 
    When I look at the autocorrelation spectra, the C-band situation is 
much more benign, with the power added by the interference adding only a 
few percent over the receiver noise power (when looking at the NCP). 
    The S-band situation remains serious however -- Sirius and XM radio 
completely overwhelm the autocorrelation spectra, so no estimate of the 
added power can yet be made via the autocorrelation spectra.