Below is an example of a file for a VLBI observation that uses the phased VLA. For phasing, a source is used that can also be used as a VLBI phase or fringe fitting reference. All antennas are sent to the reference and VLBI data is taken on it. This is now the prefered style for phasing. Of course the VLAPSRC parameter could also have been used if non-recording scans with only the VLA on the calibrator had been desired.
Note that the main example in the Examples section has a single VLA antenna in it and serves as an example of that type of observing.
! Start file bw099.key. Example of a VLBI observation using the
! VLA as a phased array.
! Original file by J. Wrobel.
! Modified for the SCHED manual by C. Walker.
! VLAINTEG added Sep. 8, 2008 RCW.
!
! ==========================================================
! ================= Cover Information ====================
! ==========================================================
expt = 'bw099 1cm 15jan97 Wrobel'
expcode = 'bw099'
version = 1
piname = 'J.M. Wrobel'
address1 = 'NRAO, P.O. Box O'
address2 = 'Socorro, NM 87801'
address3 = 'USA'
phone = '+1-505-835-7392'
obsphone = 'VLA'
fax = '+1-505-835-7027'
email = 'jwrobel@nrao.edu (internet)'
obsmode = '128-4-2'
obstype = 'VLBA'
note1 = 'VLBA target : J1220+29=NGC4278=UGC07386 ***'
note2 = 'VLBA DR check/VLA phase ref: J1221+28 ***'
note3 = 'VLBA FF/manual pcal/bpass : J1229+02=3C273 ***'
note4 = 'VLBA amp check, VLA amp std: J1310+32, J1331+30=3C286 ***'
! ==========================================================
! ============== Correlator Information ==================
! ==========================================================
correl = 'socorro'
cornant = 11
corchan = 16
coravg = 2
corpol = 'on'
corwtfn = 'uniform'
corsrcs = 'NGC4278 from schedule, else standard'
cortape = 'dat'
corship1 = 'jwrobel at aoc'
! ==========================================================
! ==================== Source Catalog =====================
! ==========================================================
! Imbedded catalog for possible non-standard source.
srccat /
source='J1220+2916','J1220+29','B1217+295','NGC4278','UGC07386'
ra=12:20:06.8243 dec= 29:16:50.716 equinox='J2000' calcode='M'
remarks='From preliminary JVAS paper III' /
endcat /
! standard catalogs
! These are the defaults - included to show format.
srcfile = $SCHED/catalogs/sources.vlba
stafile = $SCHED/catalogs/stations.dat
! ==========================================================
! ==================== Setup Information ===================
! ==========================================================
! This shows how to specify a full VLA setup when doing
! a frequency set unlike any in freq.dat. This is fairly
! common when trying to span more than the 50 MHz of a
! single VLA IF. Start SCHED and specify FREQLIST=<f1>,<f2>
! for lists of possible inputs.
setinit = '1cmwide.set' /
nchan = 4
bits = 2
bbfilter = 8.0
freqref = 22228.49
freqoff = -200.00, -192.00, +200.00, +208.00
netside = U, U, U, U
pol = LCP
/
station = vla1, vla27
ifchan = C, C, D, D
firstlo = 21410.10, 21410.10, 21810.10, 21810.10
vlaband = VK vlafeab = 17.5 vlasyna = 3510.1 flukea = 100.0
vlabw = '0000' vlafecd = 17.5 vlasynb = 3910.1 flukeb = 200.0
fefilter = '0000'
/
endset /
! ==========================================================
! ======================== The Scans =====================
! ==========================================================
year = 1997
month = 1
day = 15
start = 06:45:00
autotape = 2
stations = vlba_sc, vlba_hn, vlba_nl, vlba_fd, vlba_la,
vla27,
vlba_pt, vlba_kp, vlba_ov, vlba_br, vlba_mk
! Adopt 14 passes per tape and 44m per thin tape pass.
! Note that this sample was set up before automatic tape allocation
! was used. Keeping track of passes is no longer necessary, and
! can occasionally be counterproductive.
! Use the setup specified above.
setup = '1cmwide.set'
! Point vla27 south to make wraps predictable. Assess phasing.
! Use vlamode 'VL' to phase IFs C and D, rather than the A and D
! normally used with mode 'VA'.
source = 'J0725-00' gap = 00:00 dur = 12:00 vlamode 'VL' norecord /
! Swing vla27 to ngc4278's phase ref source.
source = 'J1221+28' gap = 00:00 dur = 05:00 vlamode 'VL' norecord /
! Do passes 1-4. This is a sequence of calibrator/source pairs.
group 2 repeat 16
source = 'J1221+28' gap = 00:00 dur = 03:00 vlamode 'VL' record /
source = 'NGC4278' gap = 00:00 dur = 08:00 vlamode 'VX' record /
! Start pass 5. Get VLBI fringe finder and VLA flux calibrator.
comment = '**** Start 1st calibration sequence.'
! vla27 mode VA is ok for J1310+32 but not for 3C273.
! vla27 mode VX for 3C286 to hold phases constant.
source = 'J1224+03' gap = 00:00 dur = 04:00 vlamode 'VL' norecord /
source = '3C273' gap = 00:00 dur = 05:30 vlamode 'VX' record /
source = 'J1310+32' gap = 01:00 dur = 05:30 vlamode 'VL' record /
source = '3C286' gap = 00:00 dur = 04:00 vlamode 'VX' norecord /
comment = '**** End 1st calibration sequence.'
! Swing vla27 to ngc4278's phase ref source.
source = 'J1221+28' gap = 00:00 dur = 03:00 vlamode 'VL' norecord /
! As a demonstration, change the on-line integration time to 3 sec.
! This might allow faster phasing.
vlainteg = 3
! Finish pass 5.
group 2 repeat 3
source = 'J1221+28' gap = 00:00 dur = 03:00 vlamode 'VL' record /
source = 'NGC4278' gap = 00:00 dur = 08:00 vlamode 'VX' record /
! Do passes 6-9.
group 2 repeat 16
source = 'J1221+28' gap = 00:00 dur = 03:00 vlamode 'VL' record /
source = 'NGC4278' gap = 00:00 dur = 08:00 vlamode 'VX' record /
! Start pass 10.
comment = '**** Start 2nd calibration sequence.'
source = 'J1224+03' gap = 00:00 dur = 04:00 vlamode 'VL' norecord /
source = '3C273' gap = 00:00 dur = 05:30 vlamode 'VX' record /
source = 'J1310+32' gap = 01:00 dur = 05:30 vlamode 'VL' record /
source = '3C286' gap = 00:00 dur = 04:00 vlamode 'VX' norecord /
comment = '**** End 2nd calibration sequence.'
! Swing vla27 to ngc4278's phase ref source.
source = 'J1221+28' gap = 00:00 dur = 03:00 vlamode 'VL' norecord /
! Finish pass 10.
group 2 repeat 3
source = 'J1221+28' gap = 00:00 dur = 03:00 vlamode 'VL' record /
source = 'NGC4278' gap = 00:00 dur = 08:00 vlamode 'VX' record /
! Do passes 11-14.
group 2 repeat 16
source = 'J1221+28' gap = 00:00 dur = 03:00 vlamode 'VL' record /
source = 'NGC4278' gap = 00:00 dur = 08:00 vlamode 'VX' record /
! end bw099.key