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Medusa VLBI

Medusa is a GPU cluster used for backend processing of the Parkes UWL receiver. The UWL receiver has digitizers dedicated to the receiver in the focus cabin. There are also digitizers in the tower connected to the “legacy” downconversion system. The tower/legacy digitizers are limited to 1 GHz bandwidth (the bandwidth of the legacy system).

Experiment Setup

  • Run <exper.vex> on Marfield Unix systems, and copy to joffrey LBA area as pksobs (looks for antenna 'Md“, can be changed with -antenna XX option
  • On joffrey run:
cd lba/medusa

This starts the vlbiControl pyqt5 gui. To load an experiment click on File→Load Experiment then select the XML file for this experiment.

Start the experiment by clicking the Start button. This will configure and start Medusa and start the Flexbuf recorder running. It will NOT control the antenna or any of the IF setup.

VLBI Observing with Legacy Receivers

Proper notes to be added

  • Create Medusa config, if required (e.g. no config exists for this Rx/LO setup): {-freq <FREQ> | -DAS <FREQ> }

Copy output to medusa-srv0:/home/uwb/linux_64/share/medusa_configs. The passed frequency is the centre of the observing band. If the band is inverted, pass the -i option

  • Change Medusa config file (stop and restart needed)
  • Configure Switch Matrix appropriately
    • smrun MED64N if using LBA DAS or smrun MED900N if “1 GHz” bandwidth

Note that Medusa can be run in parallel with the LBA DAS, but in this case the Parkes downconversion will be configured to 64 MHz bandwidth per IF. This limits the total bandwidth available to Medusa to 64 MHz. If more bandwidth is required, the LBA DAS cannot be used.

lbaops/medusa.txt · Last modified: 2022/10/17 15:48 by chrisphillips