VEGAS Tests 2013 Aug 10


  • Run VEGAS with the L-band receiver, and demonstrate to Galen that the converter rack settings need to be 0dB / 35 dB
  • Run MODE2 at 8ms with the new HPCs (vegas-hpc1 and vegas-hpc2) using Lbandmode2pul and demonstrate no UT jumps
  • Run MODE2 with IF Noise Source and Lbandmode2pul - use setValues to switch IF bandwidth (filt_bw) to 950 MHz and check passband rolls off at 950 MHz.
  • Run MODE2 with L-band receiver and LO1B test tone. Check frequency switches between bins correctly

Observing details

  • Come in at 12:45 - set up CLEO, rc_vegas_system, vegasdm
  • Session number is 24
  • 13:00 - Melinda makes some software changes (not sure what)
  • 13:45 - Anish wants to test the frequencies in GBTIDL - runs scans 1-6
  • Scan 1-4 are in Session 24, 5 & 6 in Session 25 - Switch to Session 26
  • Scan 8 - Lbandmode1pul on 3C286 - 30 sec scan. Astrid balances to ~ -21dBm, and vegasdm agrees with this
  • Scan 9 - manually switch to noise source in IFRack - balance and observe "3C286" again
  • Scan 10 - need to also set noise source filter to "broadband" using DeviceExplorer
    • now have signal across the whole bandpass
  • Scan 11 - use DeviceExplorer to change filter_bw to 950 - seems correct
  • Scan 12 - use DeviceExplorer to change filter_bw to 1150 - seems correct
  • 15:15 - switch back to Anish and Mode2 tests again. Session is changed back to 25
  • Anish tests MODE2 and 3 - no data
  • 15:40 - switch to Amanda Kepley - all seems to work ok after Melinda debugs a configuration problem.
    • Data is in TGBT13B_502_02
  • 16:55 - all done

Issues and Notes

  • Melinda's frequency fix is only temporary, not permanent
  • vegasdm - tries to connect to all banks, even though only BankA and BankB are active
  • gbtidl-test can do a summary on Bank B, but doesn't seem to be able to get any data (e.g. scans 1-4) Perhaps BankB was in exitting?
  • why in gbtidl does it show nIF = 1 when there are two polarizations?
  • sdfits-test won't fill mode2 data This is important - probably because there is no data in the file!
  • scans 5-7 didn't write any data, but no error messages - maybe integration time was too short?
  • VEGAS filter_bw stayed at 1150 - even after Anish re-configured. problem with config_tool?
  • Scan (SIMPLE, Track) not handled by the Spectral Line plugin. Should it be?
  • MODE2 is not taking any data this is a serious problem
  • MODE3 is not taking any data this is a serious problem
  • What is the correct balance, -20dBm or -25dBm ?
Topic revision: r2 - 2013-08-10, RichardPrestage
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