[daip] elevation flagging in UVFLG

[Lynn D. Matthews]

I've tried out the new elevation flagging in UVFLG, but I can't seem to
get it to flag anything. I'm trying it on a compressed, multi-source VLBA
data set where I've verified that I have data in the elevation
ranges I'm trying to flag.  Perhaps I have some input set incorrectly? I
always get the message:

RGLINU> UVFLG1: Task UVFLG  (release of 31DEC07) begins
RGLINU> UVFLG1:
RGLINU> UVFLG1: Nothing was added to FG table   4
RGLINU> UVFLG1: Appears to have ended successfully

Sample inputs are as follows:

AIPS 1: UVFLG:  Task to Flag selected UV data on disk.
AIPS 1: Adverbs     Values                 Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: INNAME     'BG118K'                UV data (name).
AIPS 1: INCLASS    'FITLD'                 UV data (class).
AIPS 1: INSEQ         2                    UV data (seq. #).  0 => high
AIPS 1: INDISK        3                    Disk unit #.  0 => any
AIPS 1: INFILE     *all ' '                Text file name.
AIPS 1: SOURCES    '0458-020'              Sources selected/deselected
AIPS 1:            *rest ' '
AIPS 1: SUBARRAY      0                    Subarray number 0=>all.
AIPS 1: SELBAND      -1                    Bandwidth to flag (kHz)
AIPS 1: SELFREQ      -1                    Frequency to flag (MHz)
AIPS 1: FREQID       -1                    Freq. ID to flag. -1=>all.
AIPS 1:                                    0=> first Freq. ID.
AIPS 1: TIMERANG   *all 0                  Time: start day,hr,min,sec
AIPS 1:                                          stop day,hr,min,sec.
AIPS 1: BCHAN         0                    First frequency channel
AIPS 1: ECHAN         0                    Last channel 0=>all
AIPS 1: BIF           0                    First IF 0=>1
AIPS 1: EIF           0                    Last IF 0=>all
AIPS 1: ANTENNAS   *all 0                  Antennas
AIPS 1: BASELINE   *all 0                  Baselines with ANTENNAS
AIPS 1: STOKES     ' '                     Stokes' parameters
AIPS 1: FLAGVER      99                    Flag table version number
AIPS 1:                                       Used w single-source too
AIPS 1: APARM         0           0        Clip on ampl. and weight
AIPS 1:               0         -10        (single source data only)
AIPS 1:              10        *rest 0     1:lower limit of amplitude
AIPS 1:                                    2:upper limit of amplitude
AIPS 1:                                      0 => use defaults
AIPS 1:                                      sign is significant!
AIPS 1:                                    3:limit of weight
AIPS 1:                                    The data with ampl. outside
AIPS 1:                                    of a given range or  weight
AIPS 1:                                    less the given value are
AIPS 1:                                    flagged (unflagged)
AIPS 1:                                         Elevation flagging
AIPS 1:                                    4:elevation lower cutoff deg
AIPS 1:                                    5:elevation upper cutoff deg
AIPS 1:                                    6:Factor of suppression of
AIPS 1:                                      spurious fringes caused by
AIPS 1:                                      pulse cal when fringe
AIPS 1:                                      rate close to zero.
AIPS 1:                                      It must be >1
AIPS 1:                                      0 => do not flag due to
AIPS 1:                                        this reason
AIPS 1:                                    7:>0 => Print source, time,
AIPS 1:                                       baseline,  U,V of expected
AIPS 1:                                       zero fringe rate (U=0)
AIPS 1:                                      0 => do not print
AIPS 1:                                    APARM=0 => flagging(unflag.)
AIPS 1:                                    does not depend on APARM
AIPS 1: OPCODE     'FLAG'                  'FLAG','UFLG'
AIPS 1: REASON     'LOW EL'                Reason (24 char.)
AIPS 1: BDROP         0                    First vis. no. to flag
AIPS 1:                                      (not with flag tables)
AIPS 1: EDROP         0                    Last  vis. no. to flag
AIPS 1:                                      (not with flag tables)
AIPS 1: DOHIST        1                    > 0 -> add to history

Lynn Matthews