[evlatests] NexRad!

[Rick Perley]

    Dan Merteley has suggested that the pulsed signal I reported on is 
from NEXRAD -- the NWS' Doppler weather radar system.  The odds are good 
he's right ...

    Checking Wikipedia, I see there is a system which runs with 4.5 
minute period -- presumably the 'minute' should be 'second'.   And, by 
looking more carefully at the spectral data, I found the signal in the 
autocorrelation spectra.  It is not wideband (my error), but is at:  
2740.5 MHz.  I can also see a weaker pulsation in subband 7:  2810 MHz.  
And there may be a third one, in subband 6, near 2700 MHz.
    As it turns out, there are three NEXRAD systems in NM (Holloman, 
Cannon, and Kirtland). 
    None of these pulsed signals can be seen in the visibilities, so 
there is zero threat to the visibility data.  And, with a period of 4.5 
seconds, only one if four of the SY table values are in error.  It's 
easy to purge these in SNEDT.