[evlatests] P-Band Status, 1 August

[Rick Perley]

    I checked P-band, in continuum, yesterday.  The usual 416 ms dump 
time, on a strong source.

    Nine EVLA antennas are now working at P-band.  Antennas 13 and 16 
are the non-functional ones. 

    Noted Problems with EVLA antennas:

    1) Antenna 11 fringes on all IFs, but is weak by a factor of a few. 

    2) Antenna 17, IF#2, is flagged as bad, but in fact provides good 
data. 

    Problems with VLA antennas:

    1) Antenna 4 is dead in RCP.  Curiously, this fact is known in IF 
'B', but not in IF 'A'. 
    2) Antenna 4 is very unstable in LCP (and not flagged). 
    3) There are large phase excusions (offsets) in 3 B and 3D.   These 
offsets are identical in the two polarizations.
    4) The phases in 12A and 12C are slowly wandering (not ionosphere!) 
by large values (tens to hundreds of degrees).  This problem is seen at 
L-band also. 

    Initial flagging is good, but I note there is a remarkable range of 
time taken for the various antennas to settle down from the previous 
observation (taken at L-band).  Some antennas were 'ready to go' within 
20 seconds, others took up to 40 seconds.  Not a big deal, but other 
band changes are much more uniform in the time taken. 

    There were two records -- unflagged -- at the beginning of this scan 
which 'belonged' to the previous observation.  The data were just noise, 
and were separated from the good data by 20 seconds or more -- (so were 
easy to find and remove), but nevertheless, point to some confusion as 
to ownership.