[evlatests] Some Unusual RFI at X-band

[Rick Perley]

     A 2-hour observation of a northern source taken two days ago has 
revealed a most unusual array of RFI.  In the observation of the 
calibrator J1800+7828 -- and this source only -- exactlu seven RFI 
'lines' were seen.  The seven lines are equally spaced -- exactly 60 MHz 
separation -- and all of them are clearly resolved -- a width of 8 MHz.  
The frequency of the lowest line is 9518 MHz.

     These lines are seen equally in both polarizations, and were seen 
equally on all baselines connecting to two antennas (I haven't checked 
them all -- that's a lot of baselines ...). Presuming all antennas are 
affected, this suggests the RFI is external in origin.  The lines are 
not terribly strong -- probably tens to hundreds of Jy.

     Any idea of the origin?

     Rick