[evlatests] L-Band Phase Stability and Polarization

[Vivek Dhawan]

The RTP meters recorded 7.5 x10^-3 turns/hr during Rick's run.
At 1536MHz, this is only 16 deg/hr of phase change, assuming
the IF return fiber (not monitored) behaves like the monitored
LO fiber. The rate is therefore much more than we usually see.
I retract my earlier comment to Rick.

Conclusion: he done broke it again.

Rick Perley wrote:

> 
>     All EVLA antennas have a very strong phase gradient w.r.t the VLA 
> antennas of about -85 degrees per hour.  The opposite polarizations are 
> identical.  I cannot determine the difference between IF pairs, as only 
> one was observed.
>     The EVLA antennas' phase drift w.r.t an EVLA antenna is much 
> reduced, but still very evident.  When referenced to EVLA antenna 14, 
> the residual phase drift is approximately proportional to both frequency 
> and distance from antenna 14. 
> 
>     Vivek believes the drifts are largely due to RT phase not being 
> applied, and is independently trying to confirm this. 
>