[evlatests] RFI in C-band

[rperley at nrao.edu]

I forgot to note in the previous email the observed state of RFI within
C-band.

The bottom two subbands (covering 3952 through 4208 MHz) were filled with
RFI, visible on all baselines.  The nature of the amplitudes and phases
clearly indicates multiple origins -- as expected if the sources are
satellite downlinks.  I doubt these two subbands are of any use to
astronomy without some sophisticated removal techniques.

The pair of local RFI (telecommunication links) that I reported on
yesterday are present.

Surprisingly (given the reports from others), I could see no strong
interference between 7 and 8 GHz.

The entire 1024 MHz-wide bandwidth in X-band looks clear of RFI.