[evlatests] ea02 summary

[Ken Sowinski]

Collimations have now been set for all bands, including Q band.
Performance is about what we expect at X and K bands and, maybe,
Q band as well.  However all is not well at L and C bands.

C band is clearly worse than all the other EVLA antennas, and
some VLA antennas.  At L band the fringe amplitude against a
good antenna is about half what we expect; about one-fourth
in power.  I have looked for culprits and have found none.
since the problem is much worse at L band I have looked for
causes there.  It is not optics or T_sys because the deflection
in total power going on and off 3C273 is the same as another
EVLA antenna.  Delay errors are of order a ns.  That only leaves
an LO coherency problem, but it is hard to see why L band is
affected more than C band; and why K and Q bands are unaffected.
Crossed hand power in L band is a small fraction of parallel
hand power so we do not have an OMT problem.

Any ideas?