TGBT15A_915_71 - VPM Raw Mode Testing


  • Test VPM Raw mode by looking at bright pulsar B1937+21


  • Start around 1:15pm
  • Select L-band to be in focus
  • Telescope still undergoing maintenance
  • As noted by Justin, the CLEO VEGAS display has to be restarted after a version change. This is unusual behavior, and could easily catch people out, as most of it looks like it is working.
  • Through device explorer, set next scan number, and source name to be Test_B1937.
  • Attempt to validate the script. Get an error that the data rate is too high. Increase the tint by a factor of 16.
  • Try to run, but get a warning that numchan and nchan are not equal, and an error that subband is not 1.
  • Edit the script to fix this, now seems to execute ok.
  • Still no control of telescope - but it may be moving manually.
  • Scan 1 - VPMRawModeTest_B1937
    • IF Manager gives a warning that VEGAS J9 through J16 has no IF signal.
  • Scan 2 - repeat
  • Scan 3/4 - try one invocation of CheckMode1_rmp, to see if it recovers from being in Pulsar Mode.
    • Runs with no errors, but GBTIDL will not display it! Maybe because we were still at X-band? Switch to L-band.
  • Scans 5/6 - now looks all ok (lots of RFI).
  • Antenna is now enabled.
  • Scan 7 - VPMRawModeTest_B1937
    • All eight banks are in subsystem_select, but only Bank A should be.
    • input power level on VEGAS CLEO screen is blue (normal) for Bank A, but orange for the others. I have never seen this before.
    • The power levels into the other banks are still reasonable.
    • sw_period is 6.82666 e-07, but VEGAS does not display the "e-07", so it looks like 6.8 seconds.
  • Repeat - scans 8 and 9
  • Stop after scan 9 and switch to pointing for a while

-- RichardPrestage - 2016-11-10
Topic revision: r2 - 2016-11-14, RichardPrestage
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