Radio Astron

Ceduna

Ceduna is responsible for the majority of the RadioAstron observations supported by UTas. The recordings are made using the DBBC and mark5C recorder. Please note that this must be taken into account when drudging the experiment VEX files.

drudging the VEX file

First download the VEX file. This is generally distributed via email (from ra_vex@asc.rssi.ru) and is also available from the ATNF FTP server (if another mainland LBA station is included) and from the RA FTP server(ftp://grt:K0&th%@webinet.asc.rssi.ru/schedule/grtsched/RAKS/rk16am) to /usr2/sched/.

You can then drudg the schedule with drudg rk16am.vex. Check that the equipment is set (with menu 11) to DBBC/Mark5b/None/None with 18 14 1 1. Then produce the procedure file with menu 12 and the snap file with menu 3.

You then need to append some extra procedures to the prc file, to enable system measurements, etc. There are three files for the different RA frequencies in /usr2/proc - append the relevant one to the procedure file with cat /usr2/proc/systempcdRA1668.prc >> /usr2/proc/rk16amcd.prc

Configuring the DBBC/Fila10G/Mark5C

With the correct receiver on axis, load the procedure file (with proc=rk16amcd) and then run sched_initi and setup01. These will set the Agilent frequency and set up the DBBC. Check the DBBC power levels with iread and bread. The iread results should have the measured power levels with ~500 units of the target. If this is not the case (and the attenuation is at one of the limits of either 0 or 63), please adjust the DAS attenuation using the folly. The bread readings for BBCs 1 and 5 should be ~16000, and the attenuation should not be at the limits (0,255).

Next, in a terminal as oper@pcfscd, run ./configure_fila10g.sh. This script sends commands to the fila10g to configure the channel selection and then runs a test recording. Check that the output line reports that the timestamps in the recorded data match (to within 0.01s). If not, please re-run ./configure_fila10g.sh until this works.

Fringe-checking with the LBA

Load the schedule
Issue a "halt" and "disk_record=off" to make sure the fringe recording does not interfere.
Make a fringetest recording with ./fringe_recorder.sh test 3 as oper@pcfscd. Wait ~5 seconds.
on mk5cd, check the time of the recorded file with m5time /mnt/cdvsi/fringtest/test.m5a Mark5B-256-4-2. Report the timestamp to then LBA chat.
Run "cont" to continue the schedule.

Verbose equivalent

Unfortunately, the fringe-check files produced by the LBA schedule do not work well with the Mark5C. Rather than running a fringe-check schedule, instead make sure you are tracking the correct source (use the source command). Edit the fringe_recorder.sh file (on pcfscd) to select the output destination - this is currently set to /mnt/cdvsi/fringtest. /mnt/cdvsi is the /exports/xraid/Ar_1/ drive on cdvsi, NFS mounted onto the Mark5cd recorder (mk5cd). Recording the data to cdvsi makes it easier for Chris Phillips RtFC scripts. Once a suitable location is selected, you can record some fringe test data with ./fringe_recorder.sh test 3 (on pcfscd). This will create a file called test.m5a, containing 3 seconds of data. You can get the time of the recordings (which is needed for the correlation) with the command m5time /mnt/cdvsi/vc317/test.m5a Mark5B-256-4-2 (you need to run this command on mk5cd, not pcfscd) and check the clock offset with the clkoff command.

Running the experiment/Checklist

Start the schedule with schedule=rk16amcd,#1 as usual. Check that the clkoff readings are sensible and that the system temperature is being measured in the preob. Also look for an onsource TRACKING response.

After the experiment

Stow the antenna if there are no further experiments planned. If Vela is up and L-band receiver is mounted, Jim P's observations could be restarted.

Hobart

Hobart now only uses the DBBC/Mark5B backend configuration to support RA observations. This does cause some extra complications in setting up the Field System, but does remove the need to BG3 cable swaps which otherwise cause major disruptions to the ongoing Vela monitoring.

drudging the VEX file

Changing the FS configuration

Generally, the FS is set up to use the mark4 rack, and mark5a recorder. To change the backend, please use the following command (as oper@hobart:

cd /usr2/control; cp equip.dbbc2.1gbps.ctl equip.ctl ; cp mk5ad.mk5ho.ctl mk5ad.ctl

Then terminate the Field system and restart. Test that the correct backend is loaded by running fmset in a hobart terminal - it should report the backend & recorder as DBBC and mark5b.

Configuring the DBBC/Mark5B

With the correct receiver on axis, load the procedure file (with proc=rk16amho) and then run sched_initi and setup02. These will set the Agilent frequency and set up the DBBC. Check the DBBC power levels with iread and bread. The iread results should have the measured power levels with ~500 units of the target. If this is not the case (and the attenuation is at one of the limits of either 0 or 63), please adjust the DAS attenuation using the remote backend (Palfreyman's Delight). The bread readings for BBCs 1 and 9 should be ~16000, and the attenuation should not be at the limits (0,255).

NB - For L-band, please make sure that the Quadrature Hybrid is IN, and that the input selection in the remote backend is LCP/RCP rather than the usual RCP/LCP

Fringe-checking with the LBA

Fringe checked schedules produced by the LBA scheduler should work automatically. The only extra step required is setting the output directory for the data extracted from the mark5 modules. When drudging the fringe check files, select menu 15 (data transfer override) and set the output directory using menu 10, e.g 10 /mnt/hovsi/vc317/ would use the /mnt/hovsi/vc317 directory on mk5ho. In the case, /mnt/hovsi is the /data/removable drive on hovsi, NFS mounted to mk5ho as this simplifies things for the RtFC script. You can check the timestamps of any exported data with m5time /mnt/hovsi/vc317/vc317a_ho_no0001.m5a Mark5B-256-4-2 (as oper@mk5ho).

Running the experiment/Checklist

After the experiment

Restore the default FS configuration with:

cd /usr2/control; cp equip.mk4.ctl equip.ctl ; cp mk5ad.mkv.ctl mk5ad.ctl

Terminate the FS, and then restart it. You should then restart Jim's Vela monitoring - instructions are here