[evlatests] P-band status (as of yesterday morning)

[Rick Perley]

    From the Tuesday morning test, I find:

    1) No fringes from ea01, ea19, or ea21.  (First two have no 
receiver, last one is in the barn). 

    2) Polarization reversed on:  ea03, ea09, ea14, and ea26.   (Can 
somebody please address this -- although we can fix this in software, 
it's a nuisance!). 

    3) Zero-mean PDif (which means that the values obtained have an 
average of 0 counts, but with a normal dispersion) on ea10, ea13, ea25 
and ea27. 

    4) Variable, or unsteady PDif is found on:  ea02, ea12. 

    5) Significant 'PDif Compression' (meaning, the PDif values on Cyg A 
are notably lower than on other target sources)  on ea17 and ea18.  
(This is very good -- the compression, at least at the lower power level 
setting that I used for this test, appears to be significantly less at 
P-band than at the other bands).   I'll generate a table later to show 
the compression distribution

    I ran this test in a 16 subband mode, each with 16 MHz BW.  The 
quality of the data (both the visibilities and the switched power) is 
very good.   There is enough 'clear space' within each subband to enable 
reasonable calibration.  I attach a .png file which shows the 
cleanliness of the data.  The horizontal axis is frequency, the vertical 
is time (from bottom to top).  This was taken on baseline 02-18 (N06 -- 
E18 -- about 2.5 km length).  The left edge frequency is 236.0 MHz, the 
right edge is 492 MHz.  The center is thus at 364.0 MHz.  This spectrum 
is typical -- although the very short baselines show the expected 
degraded response in the 'RFI-strong' zones.  These are raw data -- no 
calibration of any kind.  The brighter horizontal bars are the 
visibilities from Cygnus A.  The two darker ones are from 3C295 and 
3C48, respectively. 

   
   
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