VEGAS Team Meeting

Agenda:

1. Summarize the current status of the INTEGRAT / LO blanking / mixed mode work
2. Frequency switching issue (reported today)
3. Progress on the “missing channels” problem
4. ADC calibration (summary of "ripple test success" email thread)
5. Gather, and prioritize maintenance time requests. Maintenance days will be Tuesday and Thursday (all day)
6. Status of shared-risk astronomical observations: https://safe.nrao.edu/wiki/bin/view/CICADA/CICADAGreenBankSpectrometerAstronomicalObservations
7. Status of other “current issues”: https://safe.nrao.edu/wiki/bin/view/CICADA/CICADAGreenBankSpectrometerCurrentIssues

Meeting notes:

1. Summarize the current status of the INTEGRAT / LO blanking / mixed mode work
   • Installed - tests do not show any occurrences of the problem additional tests Thursday
   • LO-blanking of 3ms set for all modes - covers longest amount of blanking
2. Frequency switching issue (reported today)
   • Data taken as part of Thursday tests above
   • Looking at data manually in GBTIDL it looked okay, the issue is the "mirror images" on either side. Seen when data is processed, but not a real signal
   • Maybe a test tone injected into the system would confirm this problem - Tuesday?
   • Some channels had negative values, almost like Mode 4 issue - Joe to investigate.
3. Progress on the “missing channels” problem
   • try and do some tests when Jayanth is available.
     • [Issue] There have been a lot of code changes since Jayanth has last seem code - how will this be efficient?
   • Found in older data, then fixed, and now back again. Need dates from data collection to reconcile against other system changes
     • Amanda to send Joe a listing of Science data to date for analysis
   • Joe to run same scripts on last Thursday's Mode #4 data to see if problem occurs (32k channels common aspect?)
   • Could this be a timing issue?
4. [Resolved and Decided] ADC calibration (summary of "ripple test success" email thread)
   • Paul's proposal is still the baseline - confirmed by the three items in Anish's email
     1. Implement Paul's MMCM suggestion and let us get some experience in how `bad' things are.
        • Documented in MR: https://safe.nrao.edu/wiki/bin/view/GB/Software/ModificationRequest1Q3
          • M&C portion of MR may be ready for deployment by next week
     2. Improve the reliability of MMCM calibration (as Jack suggested).
     3. Implement MMCM calibration each time bof is reloaded.
5. Weekly testing schedule
   • Tuesday (all day)
     • 8:30am - 11:00am [Priority 1] Test time to confirm 'Frequency Switching' problem (consult w/Anish for the kind of data he would want) - Brandt/Kepley
     • 1:30pm - 4:30pm [Priority 2] Test time for a series of Mode #4 data collection for the composite view of the different parameters used. Many short scans more useful than few long scans (60 sec w/multiple integrations per scan). - Kepley
   • Thursday (likely afternoon) * Subreflector testing Thursday 2:00 – 4:00pm - Prestage. (Doesn't prevent VEGAS testing, but we’ll need to coordinate with any VEGAS testing)
     • Missing channels testing w/Jayanth (if not Tuesday
6. Status of shared-risk astronomical observations: https://safe.nrao.edu/wiki/bin/view/CICADA/CICADAGreenBankSpectrometerAstronomicalObservations
7. Status of other “current issues”: https://safe.nrao.edu/wiki/bin/view/CICADA/CICADAGreenBankSpectrometerCurrentIssues

Other

1. Please make sure to properly code your timesheets for the current time period and going forward.
   • Software engineers should be using a GBT ops software CM&E account - Account 893252
   • Electronic engineers should be using a GBT ops electronics CM&E account - Account 432510
   • Commissioning activities should be getting charged to hardware support and testing - Account 432510
   • Scientists assisting with shared-risk commissioning should be charging an observer support account
     • 432540 for the most part. Accounts 142020 (GB-based staff) and 142010 (CV-based staff) for when you are helping with overarching observing support (not problem solving, VEGAS specific)