[evlatests] C band gain instabilities

[Michael Rupen]

In a run early this morning (11mar10) at C band, ea06-D moved back and
forth between two amplitude gains separated by about 10%.  Jumps occur in the
middle of and between scans, and take a few seconds to get from one state
to the other.

ea26-D moved down in amplitude by about 4% over a few seconds in the middle
of one scan.

All other antennas/IFs look much more stable, including ea03.

All antennas looked stable in phase over ~30 minutes, but the weather was
not great.

            -- Michael