S2 VLBI Setup

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.

$ caobs
  CAOBS> corr closef                  ! start new RPFITS file
  CAOBS> set file ...
  CAOBS> set rise 200
  CAOBS> set ref ca06
  CAOBS> set lo_track_off             ! no LO tracking
  CAOBS> track 1

Wait until tracking a source -- ! ( set bypass ?? )

  CAOBS> dis auto
  CAOBS> set atten ca06 nnnn

Antenna setup:

RCP ==> A    LCP ==> B

Fobs   BW    F(if)   -->DC  F(fluke)*  (dBm)   F(S&D)  Sideband* 
----   --    -----   -----  --------   ----    ------  --------  
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.
  
$ caobs_param
  S et
  G lobal
    Conversion chain [1,2]? 1
  P hase
    eg. 6 B 20            ! increment phase of B1 by 20 deg.
  CR
  CR
  CR

S2 setup:

S2> log clear
S2> time ( eg. time 180-22:00:00 )            ! Phone (0) 1194
    --> and hit return after the third pip.

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 CULGOORA
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:

$ 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.

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:

CAOBS> stop                        ! Note: You may need to close the 
CAOBS> start                       !   RPFITS file during a tape change 
CAOBS> set tton                    !   so that it does not exceed 500000 
                                   !   blocks.
S2> stop
S2> eject

change tapes

S2> tapeid ATNF nnnn
S2> rewind
S2> record

CAOBS> set ttoff

Resynchronize the clock on NOEL:: about once per day:

In CACOR type

CACOR> settime

On CAOBS type

CAOBS> systime

Other S2 Commands

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 ---

rewind
wait stop
record
<esc>                         ! <esc> back to command mode
x                             ! delete
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 logfile

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> enab auto
CAOBS> set rise 0
CAOBS> set lo_track_on
CAOBS> set ref ca03

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  ! Eg. 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 (2-JUL-1995)
Modified: Nuria McKay (9-OCT-1995)