AIPS HELP file for SNREF in 31DEC22
As of Tue Jun 6 3:57:00 2023
SNREF: Task to choose best reference for R-L phase difference
INNAME UV data (name).
INCLASS UV data (class).
INSEQ 0.0 9999.0 UV data (seq. #). 0 => high
INDISK 0.0 9.0 Disk unit #. 0 => any
INEXT Input 'SN','CL'
INVERS Input table file version no.
SELBAND Bandwidth to plot (kHz)
SELFREQ Frequency to plot (MHz)
FREQID Freq. ID to plot, -1=>all
SUBARRAY -1.0 Limit to subarray; <=0 -> 1
DOKEEP -1.0 1.0 > 0 => keep all "temporary"
Use: Tries re-referencing an SN or CL table to see which reference
antenna minimizes the R-L phase scatter. The task loops over
all possible reference antennas copying the requested SN or CL
table to a new version and re-referencing it. This
re-referenced table is then read and the normalized gains in L
are subracted from those in R and averaged in real and
imaginary parts separately. The two rmses for each IF are
added in quadrature and saved. After all possible reference
antennas have been evaluated, the rmses are examined. The
antenna with the lowest rms (averaged in quadrature over all
IFs) is reported as are the lowest antennas in each IF. The
rmses are then shown in detail.
The output file will have 1 new SN or CL table if DOKEEP is
false. If DOKEEP is true, it will have one for each of the
possible reference antennas for your examination (with e.g.
INNAME.....UV file name (name). Standard defaults.
INCLASS....UV file name (class). Standard defaults.
INSEQ......UV file name (seq. #). 0 => highest.
INDISK.....Disk unit #. 0 => any.
INEXT......'SN', or 'CL' table to be analyzed.
INVERS.....Version number of table to analyze, 0=>highest no.
SELBAND....Bandwidth of data to be selected. If more than one IF is
present SELBAND is the width of the first IF required.
Units = kHz.
SELFREQ....Frequency of data to be selected. If more than one IF is
present SELFREQ is the frequency of the first IF required.
Units = MHz.
FREQID.....Frequency identifier to select (you may determine which is
applicable from the OPTYPE='SCAN' listing produced by
LISTR). If either SELBAND or SELFREQ are set, their values
overide that of FREQID. However, setting SELBAND and
SELFREQ may result in an ambiguity. In that case, the task
will request that you use FREQID. -1 => all, 0 => first
SUBARRAY...Limit display to specific subarray. <= 0 -> 1.
DOKEEP.....> 0 => keep all temporary SN/CL tables, else keep only
the selected one.