[evlatests] 3 dB tracking tests, June 2006

[Ken Sowinski]

I report here on VLA, as well as EVLA results, so the
distribution is, perhaps, broader than needed.

Two attempts were made to do tracking tests including EVLA
antennas with the VLA.  Neither was entirely successful,
but for different reasons.

1.  It was tried under reasonable weather considitions
during startup on June 22.  Good results were obtained
for VLA antennas, but the EVLA antennas were not properly
synchronized to the test sequence.

2.  I tried it again during SW time on June 27, paying
careful attention to synchronizing the two systems, but
this time though the weather was rotten.


Results.
>From the first observation I conclude that VLA antennas
have no serious problems.  Antenna 20 looked funny, but
it must have had an independent problem at that time.
There is a hint that some EVLA antennas do have 3 dB
tracking error in azimuth, but a confirming observation
is needed.

>From the second observation the only conclusion to be
drawn is that EVLA antennas are indistinguishable from
VLA antennas when the weather is not cooperating.


Future
We need to try this again sometime under more benign
conditions to be sure that the EVLA antennas are not
misbehaving.