[evlatests] EVLA phase jumps.

[Vivek Dhawan]

Went looking for time offsets, found nothing amiss. But found
this week's Horror Show, which is EVLA phase jumps.

All EVLA antennas jump at the same time. No VLA antenna does.

Jumps happen roughly 1/hour. Not every project is affected,
but many are.

The phase difference between IF 1 and 2  is mostly a multiple
of 60 degrees, though other values are seen.

I seem to recall something about a cable needing its length
adjusted when this happened. Jim, Rob or Barry might remember
what I'm on about? I also recall that was an antenna- specific
thing, this current malady affects all EVLA antennas.
Perhaps the L350 or something else connected to the timing is
jittery?

The last good project I can find is AM979, 2009 march 10,
UT 06:00-13:00. after that (Wednesday) was TSTMAINT, MAINT,
PN3DB, APEVLA(Rick), EMTST(Emmanuel), BASEL, POINT. The last
2 were definitely afflicted, and it appears to be still
going on now. So my guess it broke last Wednesday, that's
already a 120 hours of mangled data.