Tied Array S2 VLBI Setup
- Schedule file requirements:
- Set averaging as high as reasonable to reduce the size of the RPFITS
file.
- SINGLE FREQUENCY OBSERVING:
- Set Frequency 1 to the centre of the observing band.
- Set Bandwidth 1 to the required bandwidth ( 4, 8, 16 MHz ).
- Available Correlator configuration files:
4 MHz 8 MHz 16 MHz ----- ----- ------ TDA_4_32 TDA_8_32 TDA_16_32 TDA_4_64 TDA_8_512 TDA_16_256 TDA_4_1024
- TWO FREQUENCY OBSERVING:
- Only one frequency channel is currently available with the tied array.
- Set averaging as high as reasonable to reduce the size of the RPFITS
file.
- On NOEL:: Run CAIN and start CAOBS
$ cain E xpert mode C hange cycle time cycle time = 10 sec ! Check cycle starts on 00, 10, 20, 30, 40 or 50 seconds.
On CACOR typeCACOR> settime
$ caobs CAOBS> corr closef ! start new RPFITS file CAOBS> systime ! Resynchronize clock on NOEL:: CAOBS> set file ... CAOBS> set rise 200 CAOBS> set ref ca03 CAOBS> track 1 -- wait until tracking a source -- ! ( set bypass ?? )
To turn the test tone on and off:CAOBS> set ttoff CAOBS> set ref ca06 ! Make CA06 the reference antenna CAOBS> set ref ca03 ! to stop fringes. CAOBS> set ttoff
- On ATRIA:: Start CATIE
A$ catie
-
The default setup for frequency 1 of the tied array is:
- Antennas: 12345 (ant=..)
- Chan A (RCP) Function = xx-yy (fu=..)
- Chan B (LCP) Function = xx+yy (fu=..)
- Reference = 24 (ref=..)
- Chan A (RCP) Function = xx-yy (fu=..)
- Antennas: 12345 (ant=..)
- Run CACAL
- Use interactive mode
- Calibrate delays, phases and amplitudes
- Use 90 degree option in CACAL
- If there is a lot of interference as at 1613 MHz, use a 32 channel correlator configuration, a strong source, and set CA06 as reference antenna in CACAL.
- Antenna setup (CA06)
Fobs BW F(if) -->DC F(fluke)* (dBm) F(S&D) Sideband* ---- -- ----- ----- -------- ---- ------ -------- 1191 4 70 1193 595.55 @ -17 58 LSB 1201 8 92 1205 600.55 @ -17 36 LSB 1477 16 88 1475 738.55 @ -24 40 LSB 1613 16 88 1621 810.55 @ -27 40 LSB 6669 4 70 6667 84.55 @ +0 58 USB 8420 16 88 8428 960.05 @ -10 40 LSB 12180 4 70 12182 204.975 @ +3.1 58 LSB * Test tone at F(obs) + 100 KHz.
- S2 setup:
S2> log clear S2> time ( eg. time 180-22:00:00 ) ! Phone (0) 1194 --> and hit return after the third pip.orS2> time s-3 ! to adjust the clock by -3 seconds.
Test recorders:! load 8 tapes S2> bat ber.tst ! 30 min bit error rate test. S2> bat inter.tst ! Move tapes down one recorder and measure ! error rate when played back on a different ! recorder. S2> form diag off ! ? S2> scplo mode refclk ! ?Set mode:S2> mode 32x4-2 ! 16(MHz) x 4(lines) - 2(bits) 16x4-2 ! 8(MHz) x 4(lines) - 2(bits) 8x4-2 ! 4(MHz) x 4(lines) - 2(bits) ! Note: lines = bits x polarizations S2> tapeid ATNF nnnn ! or ATNF nnnn-l,m S2> user info 1 TIED ARRAY S2> user info 2 V068 S2> user info 3 8420MHz-16MHz - load tapes - ! 2 for 4 MHz, 8 for 16 MHz. S2> rewind S2> record S2> uic dcbias n 10 s ! Check data statistics ! n=0, n=2 ==> 50% (sign bit, chan 0&1) ! n=1, n=3 ==> 34% (mag. bit, chan 0&1) ! ! ( If not recording, use "feedthru" mode ! S2> uic feedthru on) - On NOEL:: Start observing
CAOBS> start
- On NOEL:: Start VLBI_WATCH.
If VLBI_WATCH is already running, stop it and rename the log file:N$ stop vlbi_watch N$ sd at:[observer.vlblog] N$ rename vlbi_watch.log vlbi_watch_93134.log ! e.g. for a log file ! started on day 134 ! of 1993. > First copy the appropiate tcal file to TCAL.DAT > > $ sd at$calibration > $ copy tcal_4850.dat tcal.dat ! e.g. for 4850 MHz observation. > > then start VLBI_WATCH: > $ sd at:[observer.vlblog] $ vlbi_watch ! output file is VLBI_WATCH.LOG. - Change tapes
S2> stop S2> eject --- change tapes --- S2> tapeid ATNF nnnn S2> rewind S2> record
Note: You may need to close the RPFITS file during a tape change so that it does not exceed 500000 blocks.CAOBS> stop CAOBS> corr closef CAOBS> start
Resynchronize the clock on NOEL:: about once a day:On CACOR type
CACOR> settime
On CAOBS typeCAOBS> systime
Other S2 Commands
DESK2> telnet
TELNET> connect cas2 ! or cas2a
S2> status reset
S2> log display fullscreen
S2> log clear
S2> exit ! ==>
S2> shell ! ==>
S2> <ctrl> L ! redraw screen
Recording with an S2 command file: Example with 4 MHz bandwidth (2 tapes)
insert tapes
s2> group 0
S2> rewind
s2> group 1
S2> rewind
s2> group 2
S2> rewind
s2> group 3
S2> rewind
s2> group 0
s2> tapeid ATNF 0137-0,1
S2> batch edit v057.bat
i ! enter insert mode
sleep 182-05:00:00 ! wait till start
record
sleep 182-09:00:00 ! wait till next tape change
stop
eject
group 1
tapeid ATNF 0137-2,3
record
sleep 182-13:00:00 ! wait till next tape change
--- etc ---
or
stop
eject
wait stop ! wait till new tapes are loaded
rewind
wait stop
record
<esc> ! return to command mode or use
! arrow keys
x ! delete character
dd ! delete line
ZZ ! save file and exit
S2> batch verify v057.bat ! verify
S2> batch v057.bat ! execute
or <ctrl> C ! to exit from batch mode
To TELNET to S2:
L$ telnet
TELNET> connect cas2
S2> -- etc --
S2> shell
-> logout
TELNET> exit
To extract log file:
L$ telnet
TELNET> log-file v057.log
TELNET> connect cas2
S2> log display fullscreen
S2> shell
-> logout
TELNET> exit
To Finish Up and Exit from a VLBI Observation
- On CAOBS:
CAOBS> stop CAOBS> corr closef CAOBS> set rise 0 - Close S2 windiw
S2> shell -> logout TELNET> exit
- On NOEL::
Stop VLBI_WATCH and rename the log file:$ stop vlbi_watch $ sd at:[observer.vlblog] $ rename vlbi_watch.log vlbi_watch_93134.log ! e.g. for a log file ! started on day 134 of ! 1993. $ sd usr$0:[vlbi.sh93-50] ! for experiment SH93-50 $ copy at:[observer.vlblog]vlbi_watch_93134.log []
Original: Russell Gough (18-SEP-1995)
Modified: Nuria McKay (9-OCT-1995)