[evlatests] TBRISK Dec 15 UT 2225 to 2303

[Walter Brisken]

Yesterday I ran a simple continuum test file that switched between two 
sources and three bands in the following order to see when phases did not 
return to their correct value.  Except for the 5 minute first scan all 
scans were just under 2 minutes long.  Integration times were 3 seconds.

First the peculiarities of the data:
1.	L-band IF B was dead on antenna 16.  All other bands/IFs worked.
2.	Antenna 14 IF C had poor amplitude stability at C and X band
3.	(Really weird!) VLA baseline 4-28, all IFs at X-band only were very 
noisy (but shows some sign of coherence), but 4-16 and 14-28 looked fine.
4.	Antenna 14, IFs B and D showed (both LL pols) showed no fringes 
for first scan, very weak fringes on second scan, and normal strength on 
subsequent scans.  IFs A and C were OK.

Table of scans

0137+331  CC
0136+478  CC
0137+331  CC 
0136+478  CC 
0137+331  CC 
0137+331  LL
0137+331  XX
0137+331  CC 
0136+478  CC 
0137+331  LL
0136+478  LL
0137+331  LL
0137+331  XX
0136+478  XX
0137+331  CC
0137+331  XX

At every band change phases on EVLA IFs got phase jumps.

Plots are available in /home/parallax/evla/tests/20051215 -- the 6 
postscript files are VPLOT outputs.  Red is for IF A / C for RR / LL 
respectively and Blue is for IF B / D for RR / LL.  No calibration has 
been done.