[evlatests] More on Aug 25 2005 tests

[Mark Claussen]

For the data taken on August 25, I sent around a message
with sensitivity numbers, compared to the VLA for antenna
14 at X and C bands.  I have now completed the analysis
of sensitivity for An 16 as well, using spectral channels
which exclude the birdies.  By the way, I also took a look
at the autocorrelation spectra; the birdies in An 16 are
very strong in IF A and D, and ring all the way across the 
band.  There are similar birdies in IF B and C, and also
in all four IFs in An 14, but they are much weaker than
those in 16A and 16D.  It is not surprising that such a 
strong signal in An 16 (A and D) shows up in the 
cross-correlation spectra as well.  The birdies are there
at all bands and at all times in the data that I looked 
at. The other interesting thing is that the birdies are at
a constant baseband frequency when observing at different
RF bands. 

I also completed an analysis of the L-band data, essentially
ignoring the closure errors due to the source structure
of 3C273.  I thus report in my updated sensitivity table
below only the ratio of the phase rms's, since the amplitudes
after calibration are not particularly constant for differing
baselines.  I include here the entire table, repeating what
I already posted on Friday.  Again, the numbers listed here
are the ratio of the rms amplitudes and phases from An 16
or An 14 to an average of some VLA antennas.  An entry close
to 1.0 means that the EVLA antenna has a similar sensitivity
than a VLA antenna; numbers larger than 1.0 means the 
sensitivity of the EVLA antenna is worse than the VLA, and
a number less than 1.0 means the EVLA antenna has a better
sensitivity than the VLA.  (I've also quoted fewer significant
figures to better show the confidence in these numbers.)


                             X Band
         IF A          IF B          IF C         IF D

An 14 
Amp       1.0           1.3           1.5          1.3
Phase     1.3           1.3           2.2          1.3

An 16    
Amp       2.2           2.0           1.7          1.8
Phase     2.7           2.0           1.9          2.3
----------------------------------------------------------


                             C Band

An 14
Amp       1.0           1.1           2.8          0.9 
Phase     1.0           0.9           2.8          0.9

An 16
Amp       2.0           1.6           1.7          1.8 
Phase     2.1           1.5           1.5          1.6 
----------------------------------------------------------


                             L Band

An 14   
Phase     2.3           2.4           2.2          2.4 

An 16
Phase     1.6           1.0           1.0          1.1 
----------------------------------------------------------
         IF A          IF B          IF C         IF D


Mark