[evlatests] ea08 pointing

[Ken Sowinski]

ea08 behaved very badly in the pointing run this weekend.  It seems
to be a recent develpment; short pointing runs to fix moved antennas
last week did not clearly show ea08 as very bad.

The trouble is all in the elevation axis.  It looks like there
are random large offsets in the pointing determination.  Unrelated
to azimuth, time, elevation, direction of elevation motion, or anything
else I have been able to think of.  'Large' means +/- 0.5 arc-min.

Among the possibilities are

1.  It just wasn't happy that day and will look fine if we do it
     again.

2.  Something loose at the subreflector; but not an error in the
     rotation zero point or setting.

3.  Periodic el encoder error.  This should be easy to check when the
     snow abates.

4.  Something unrelated to pointing which affects correlated amplitude
     in a way to make it look like an elevation pointing error.  Unlikley,
     but listed for completeness.

I write this mainly in the hope of triggering a memory of something
done to ea08 recently that could have bearing on this.