From UTAS Radio Astronomy Group

Main: Recording Configuration DBBC Amp Mark 5 B

1 dbbc2.bit 612.99 4
1 dbbc2.bit 652.99 4
1 dbbc2.bit 752.99 4
1 dbbc2.bit 912.99 4
1 dbbc2.bit 632.89 4
1 dbbc2.bit 752.89 4
1 dbbc2.bit 812.89 4
1 dbbc2.bit 832.89 4
1 dbbc2.bit 325.99 4
1 dbbc2.bit 345.99 4
1 dbbc2.bit 365.99 4
1 dbbc2.bit 395.99 4
1 dbbc2.bit 445.99 4
1 dbbc2.bit 465.99 4
1 dbbc2.bit 319.99 4
1 dbbc2.bit 319.99 4

The 1 at the start says to use the core at the relevant address (1–16), the second line is the Xilinx config file to use (again, there is only one of these available and it is not user-configurable).

The third number is the frequency of the band edge for that module. If the upper band is selected for recording, then the number is the lower band edge. The planned connection for IVS observations is to use RCP only, with X-band into modules A and B, with S-band in C & D. This replicates the Ho setup with VCs 1–8 at X-band and 9–14 at S-band. The file shown is an adaptation of an R1 experiment (R1415 I think). The frequencies for X-band have been increased by 480 MHz (relative to Hobart’s VC frequencies) which S-band has been increased by 120 MHz. Cores 15 and 16 have “dummy” values as they are not used at Hobart.

The last number is the bandwidth of the recorded channel.


Which reports the current setup. Note that the commands into DBBC Control are very laggy - it will take up to 1 second for the commnd to be recognised. When you change settings and then check that it has worked, allow at least 2 seconds between the commands.

The output of the dbbcifa command should be of the form dbbcifa/1,36,agc,1,35347 where the first number is the filter (where 1 = 512–1024 MHz, 2 = 0–512 MHz, 3=1024–1536 MHz (Currently N/A) and 4 = 1536–2048 MHz (also N/A)), the second number (36 in this example) is the current attenuator setting (which ranges between 0 and 63 where 0 is +16 dB and 63 is −16 dB. If the reading is > 50 or < 10, consider changing the settings on the IF unit first.), agc indicates that the active gain control is enabled, the fourth number is also the filter (Maybe…), and the fifth is the current 1s averaged total power for the filter. This last value should be . You need to turn off the AGC and replace it with a single value. If the reported value was acceptable, then use in the following command


Wait 2 seconds and then check the levels with dbbcifa again. The 16 bit power level should be ~32000 ±8000. If this is ok, then repeat the procedure for dbbcifb, replacing the attenuator setting with the appropriate level but still using filter 1.

For dbbcifc and dbbcifd, these are the S-band channels and should use filter two. The initial reading will use filter 1 and report gains set to 0 and power levels at zero. Set the band correctly using dbbcifc=2,32,2 and dbbcifd=2,32,2. Wait 2 seconds and then check that the power levels are acceptable. If not, adjust the settings and/or the IF attenuator levels.


This should conclude the set up for the DBBC. Next is the Mark5B which is mercifully simpler and less prone to mysterious faults.

dimino -m0 &

In the second, run tstdimino OR use the field system to send the following commands. Into the tstdimino/fs, send the commands

Then check the synchronisation has worked with


This last command will return a string which should have the correct date and time, with syncerr_eq_0 and FHG_off. Next, set the mode on the recorder and then you can start the recording.


The :1 at the end of the line indicates how the data should be reduced. The default recording mode is 16 channels, at 16 MHz (32 Ms/s), and 2 bits per sample for a 1024 Mbps data rate. For IVS experiments recording 16 channels, the reduction value should be set to 16/bw (i.e, for an experiment using a 4 MHz bandwidth, the mode should be set to mode=ext:0xffffffff:4.

At this point, you are set to record with the tstdimino command record=on. The fs equivalents of these tstdimino commands should be something like mk5=clock_set=32:ext going from Hobart.

For IVS schedules using the 12m, there is no support for the Mark5B recorder in fs 9.9.2. When this is upgraded to 9.10, less kludging should be necessary. For now, the skd file is drudg’d with the rack set to none and the recorder as Mark5A. The procedure file is then loaded into the field system and edited (using pfmed from another terminal). The procedures to edit are setupsx (or its equivalent), preob and systemp.

In setupsx, edit the section to read


Some of these entries are probably superfluous or incorrect (especially tpicd).

preob should be edited to read


systemp should read

This last procedure is a link to a kludged bash script to make an estimate of the system temperature using the noise cal and 0.5 dB attenuators of the RF box together with some of the unused samplers in rack 1. The measured Tsys values are currently injected into the log as comments but a better solution would be to write an ANTAB file during the experiment.

Retrieved from
Page last modified on February 15, 2010, at 05:58 AM