[evlatests] Question about SY tables

[bcotton at nrao.edu]

Rick,

   The format of the SysPower.xml table makes it easy to lose entries
but if the antennas are labeled correctly, the AIPS table should be
correctly labeled.  The way to check for sure is to look at the 
SysPower.xml for the affected antenna and spectral window.  This is a
(HUGE) text file that you can look at in a text editor with zillions
of entries like: 
<row>
    <antennaId>Antenna_10</antennaId>
    <spectralWindowId>SpectralWindow_0</spectralWindowId>
    <timeInterval>4791441374499999744 1000000512</timeInterval>
    <feedId>0</feedId>
    <numReceptor>2</numReceptor>
    <switchedPowerDifference>1 2 -1.617337 0.554469</switchedPowerDifference>
    <switchedPowerSum>1 2 115.65394 114.87765</switchedPowerSum>
    <requantizerGain>1 2 512.0 512.0</requantizerGain>
</row>

Times are mjd in nanoseconds.  Note, Antenna and spectral window Ids
are NOT antenna or IF numbers and you have to look them up in the
Antenna.xml (antenna number is the integer value of the second two
characters in name) and SpectralWindow.xml (the relationship between
spectral window and AIPS 'IF" is complex) tables.

-Bill



Rick Perley writes:
 >     While editing the SY tables for the 'flux densities' data for 
 > L-band, I noted subband 4 (1180 -- 1244 MHz) has very nice switched 
 > power data.  This is unexpected, as the SPFLG plots for this subband 
 > show the presence of very strong interference -- the GPS L2 signal is 
 > centered at 1227 MHz, and should (must!) wreck havoc with switched power. 
 > 
 >     So:  The Question:  How sure are we that the SY table entries 
 > originate from the identified subband?  That is -- how sure are we that 
 > the data I'm looking at (in AIPS) which is listed for subband 4 really 
 > is from that subband? 
 > 
 >