[evlatests] EVLA Phase Stability

[Rick Perley]

    Antenna 24's phase slip, reported below, is no typo.  The phase 
changed by nearly 220 degrees over the 3 hour period.

    Rick

Ken Sowinski wrote:
> On Wed, 24 Jan 2007, Rick Perley wrote:
>
>>    Result #6.
>>
>> All EVLA antennas showed a strong phase drift with time, identical
>> between polarizations, but very different between IFs (which were at
>> 1465 and 1385 MHz for IFs 1 and 2, respectively).  The observed slopes
>> are, w.r.t VLA antenna 2 (at the center of the array):
>>
>>    Antenna            AC               BD
>> -----------------------------------------------
>>    13                   -10 deg/hr       +16
>>    14                   -27                     0
>>    16                   -33                    +3
>>    17                      0                   +27
>>    18                    -7                    +20
>>    23                    -10                  +20
>>    24                   -67                   -60
>>    26                   dead                -16
>> ----------------------------------------------------
>>
>> No VLA antennas showed anything like this -- which is clearly not a
>> baseline error.
>
> This is a clear example of Vivek's two-turn-a-day phase drift.
> What happened to antenna 24?  If that is not a typo and it is
> trying to tell us what is happening I cannot read the message.