[evlatests] Dec. 14 stress test results

[Emmanuel Momjian]

Day of observation: 61169 (Dec. 14, 2007)
Observation time-range: 19:30:00 to 20:25:51 LST
Observe file located at www.aoc.nrao.edu/~emomjian/observe/Stress14Dec.obs
Operator's log located at 
www.aoc.nrao.edu/~emomjian/observe/2007-12-14_2108_Test_Momjian.txt

The run includes both continuum (dump time 0.4 s) and spectral-line 
(dump time 10 s) scans.

Results:

1) Today's run shows that the end of the last scan is good.

2) The first (bad) record of each scan that follows a band change is 
still in the UV data (the data were loaded with on-line flagging applied 
(FILLM cparm=0 2048 0)). Examples:

Q-band scan ends at 0/21:20:30 IAT, and an L-band scan follows and shows 
(extracted from LISTR for demo purposes):

Baselines       2 3 2 5 2 6 2 7 2 8 2 9 210 212
   0/21:20:31     2  10 127  17   8  31  11  31
   0/21:20:47   145 153 151 159 166 159 151 147
   0/21:20:48   147 147 154 157 160 157 156 155

again, Q-band scan ends at 0/21:31:10 IAT, and an L-band scan follows 
and shows:

Baselines       2 3 2 5 2 6 2 7 2 8 2 9 210 211
   0/21:31:11     3   2 119   5  12  35   7   4
   0/21:31:28   144 161 159 157 157 156 160
   0/21:31:28   143 152 156 164 164 161 158 131

This behavior was also seen in the K, Q, C, and P-band continuum scans 
that followed scans from other bands. The X-band continuum scans did not 
show this, as the first X-band scan was also the first scan of the run, 
and other X-band scans were coming after an X-band pointing scan.

3) Global VLA-EVLA phase jumps are seen in all bands after the P-band scans.

4) The IF C phenomenon seen in VLA 2 (reported in the stress test of 
Dec. 9, and circulated in my email dated Dec. 12) has not been seen this 
time.

5) P-Band: (percentages below are given with respect to optimal values 
seen in most other antennas)

-EVLA 13: fringes are at 50% in IFs A, C, and D, and very weak in IF B.
-EVLA 16: no fringes in IFs C and D, weak fringes in IFs A and B (at 40% 
and 20%, respectively)
         Tsys in IF D jumps up and down between 20 K and 3500 K.
-EVLA 18: no fringes in all IFs. Tsys jumps to several 1000 K (up to 
25000 K) in all IFs.
-EVLA 19: Weak fringes is IF A, moderate in IF B (at 35%). IFs C and D 
are OK.
-EVLA 23: weak or no fringes in IF C. Other IFs are OK.
-EVLA 25: IFs A & C are at 80%, IF B has weak fringes (Tsys of 380 K), 
IF D is ok.
-EVLA 26: IFs A, C, B didn't fringe (Tsys of 1000 K or higher). IF D 
shows weak fringes (at 20%)

6) X-band: VLA 20: phase jump after the P-band observation (this is a VLA to VLA phase jump, as the reference antenna for calibration was VLA 9).