[evlatests] stress test results of Dec. 9

[Emmanuel Momjian]

The following are the results of the Dec. 9 stress test.


VLA 2: X and K bands, IF C only: the correlator coefficient values show 
a phenomenon that has a cycle time of 30 seconds: half of the cycle has 
good values, and the other half has values that go up and down by +/- 10 
to 15% with respect to the good values seen in the first half. A similar 
behavior is also seen in C-band with a shorter cycle time (about 20 
sec). The source observed in C band is different from the source 
observed in X and K bands. Nothing unusual is seen in the phases when 
the above is occurring.


Specific Bands:

K-band:
  -EVLA 26: IFs B & D have poor sensitivity compared to IFs A & C. IF B 
is worse by a factor of 1.5 and IF D is worse by a factor of 2.3 with 
respect to IFs A & C. However, the system temperature values are similar 
in all four IFs.

X-band:
   - VLA 5 and 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).

C-band:
  -EVLA 17, 21, 23, 24: short shallow drops in amplitude.
  -EVLA 26: has no fringes in IFs A, B, and D, and hardly any in IF C 
(signal to noise is so low that solutions were impossible to get).
  -EVLA 18: IF A has significantly low correlator coefficients (by a 
factor of 10). Its Tsys is 3000 K compared to IFs C & D that have 35-40K.
  -EVLA 18: IF B has significantly low correlator coefficients (by a 
factor of 42). Its Tsys is 1.5 K only compared to IFs C & D that have 
35-40K.

L-band:
  -EVLA 11, 17, 24, and 25: short shallow drops in amplitude.
  -EVLA 17: IF A has higher Tsys values compared to other IFs by a 
factor of 1.5.
  -EVLA 21: IFs A and B have higher Tsys values (factor of 2 compared to 
IFs C and D).
  -EVLA 26: IF C lots of drops in the correlator coefficient values, 
Tsys shows variations between 30 and 140 K.
            IF B Tsys shows variations between 30 and 200 K.
            IF D has correlator coefficient values lower than those in 
IF A by a factor of 2, but Tsys is the same and stable around 33.5 K in 
both these IFs.

P-band:
  -VLA 7: weak or no fringes in all IFs.
  -EVLA 13: weak fringes (the correlator coefficients are at about 50%) 
in all IFs.
  -EVLA 18: No fringes in all IFs, and Tsys values are several 1000 K 
(between 4000 and 25000 K).
  -EVLA 25: weak or no fringes most of the time in all IFs.
  -EVLA 26: no fringes in IFs B & D only.