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GBT Operations & Commissioning Meeting

25 August 2006

AGENDA

• Az Track, Antennae Report -- Bob
• Observing News -- Toney
• Scheduling Status -- Carl
• Microwave Electronics Status -- Roger
  • Operations
  • Development
• Digital Electronics Status -- Randy
  • Operations, Problem Summary
  • Development
  • Plans
• Software Status -- Amy
• Pulsar Related -- Scott
• MIT/LL 43m Project -- Glen
• Commissioning Plans -- Toney
• Any other Business

Az Track, Antennae Report -- Bob

• • Azimuth track project
    • We performed another survey Monday night. It is apparent from the data that the downward influence of the wheels extends only two plates on either side. We will be able to install the sections with a flat profile, at the existing elevation.
    • The data from the hysteresis experiment is still under evaluation, but isn't conclusive.
    • Harry obtained good data for determining the center of rotation of one corner, and it is still under evaluation.
    • I visited the company that made a set of splice plates, is making the spring plates for the 43m, and will make the bolts for the track. This is the same company that changed out the azimuth bearings on several wheels during commissioning. Very capable company. I will be discussing other work with them in the future months.

• • Structural Inspection
    • The team found a significant failure in a columnar member under the actuator room. The column is flexing the surface of the orthogonal beam above it. This whole area has suffered from a lack of attention during design in the 1990's. Art modelled it last year as part of his analysis of the walkway, and could quickly tell us that loading in this member is small, very much within the strength of the column. The orthogonal beam should have stiffeners installed inside it. While he needs a few days to make a complete design, we will be able to do an initial fix next week that will be in line with the final fix. It will require that the telescope be tilted to 40 degrees during the welding. This isn't something that we can allow to wait until next year, or even a month.
    • A second weld under the receiver room has defects from the original welding in it. This area will be repaired also before winter, but the failure above has priority.
    • A rust hole was found in a thin-walled member of the backup structure. This will be repaired also, but has third priority.

• • More info and pictures at 10 am.

Observing News -- Toney

• Subreflector (2 instances) 4.70 hours
• GASP internal clock : 1.07 hrs
• Observer not using astrid : 0.82 hrs
• Computing (3 instances, Scan Coordinator, Message Mux and Accessor) : 0.48 hrs
• Astrid (2 instances) 0.24 hrs
• No-lost-time problems : Active Surface.

Scheduling Status -- Carl

Microwave Electronics Status -- Roger

Operations

Other than fairly routine cryogenics maintenance, no problems this week.

Development

Q-band Receiver: All the system mixers were bench tested and found satisfactory for use. We now have in hand enough LNA's from CDL to complete assembly. However, the gain flatness of some of the new amps is not as good as expected, so gain equalization is being investigated. An IF amp designed for the Optical Driver modules is being evaluated for use in the receiver - it has potential advantages over the commercial amps used previously.

Ka Receiver: MMIC problems corrected, amps tests came out well. 300K assembly nearly complete, needing a few K connector and .141 coax assemblies. Card cage tests going well, no problems yet. Receiver should be assembled Friday the 25th to start cooling.

C-band: The new cryostat and heat shields are at Alexandria Metal Finishers. Component testing for the electronics redesign continues; some components have been ordered.

IF Improvements: The remaining buffered power divider assemblies are about 30% completed.

Penn Array: In the outdoor test building for cooldown and testing.

Digital Electronics Status -- Randy

Operations, Problem Summary

Development

Plans

Software Status -- Amy

This ends the first full week of 6 in the sixth development cycle of 2006 which can be viewed at PlanOfRecordC62006. We are scheduled to release on September 29.

We have been very busy with Penn Array support this week. Our testbed computer, spider, has been found to be much faster than Penn's machine. So spider is being prepared to go into the telescope in lieu of the Penn machine. To support this, we added a GPIB card and driver to run the housekeeping/cryo equipment. From a software point of view, things look good!

MelindaMello will be attending Virtual Observatory (VO) school in September.

Operational support was very light.

Modification Requests:

• MRs ready for release:
  • Allow Saving of Invalid Scheduling Blocks (ModificationRequest4C805)
• MRs ready for sponsor testing:
  • Implement Spectrometer Bad Lags Fix (ModificationRequest15C306)
• MRs under development:
  • Implement Linux Quadrant Detector Manager (ModificationRequest9C306)
  • Add Zpectrometer Control Interface to LO1Manager (ModificationRequest3C506)
  • Modifications to Ka Manager (ModificationRequest1C506)
• MRs under CCC review:
  • LO1 Test Tone Control via RPC for Zpectrometer (ModificationRequest3C506)
• MRs being written:
  • Integration of the Zpectrometer into SDFITS and GBTIDL (ModificationRequest4C406)
  • Incorporate OOF Holography Zernike models into Active Surface (ModificationRequest1C406)
  • GBTIDL Autoflagger (ModificationRequest2C506)
  • Zpectrometer config tool changes (ModificationRequest1C606)
  • Ka config tool changes (ModificationRequest4C606)
  • Modify SDFITS to correctly show Spectrometer cross-polarization data (ModificationRequest2C606?)

Pulsar Related -- Scott

MIT/LL 43m Project -- Glen

Normal spacecraft tracking this week. Request for quote received from MIT/LL. We are working on changes to the statement of work for 2007.

Commissioning Plans -- Toney

Commissioning Summary & Milestones: Sept 1 - Dec 31:

• Every month : Pointing -- 1 night/month except in November, A/B weather, dynamically scheduled.
  • Aug pointing completed, data reduced, all looks OK.
• Aug 28 : C-Band off telescope, Penn Array on telescope in its place.
  • Delayed until Aug 30 due to slower than expected cool-down time, should not affect early Sept commissioning.
• Sept 4 - Oct 27 : Penn Array commissioning -- 1 night/week, A-weather, dynamically scheduled. 8 nights max.
• Sept : Ka and Q-band lab tests
• Week of Oct 2 - week of Oct 12 : Penn Array backup daytime engineering time : 4 day-times max.
• Week of Oct. 9 : Ka-band placed on telescope
• Oct 16 - Nov 13: Ka-band spectral-line commissioning -- 1 night/week, A-weather, dynamically scheduled. 3 nights max.
• Oct 16 - Nov 13: CCB quick checkout (2-3 hours), time permitting.
• Week of Oct. 23 : Q-band on telescope
• Week of Oct. 30 (earlier if it's practical and if the astronomy schedule has no conflicts): Ku-band down, X-band moved to where Ku was, Zpectrometer on telescope where X was
• Week of Nov. 6 : Penn Array down, C-band up in its place.
• Nov 6 - Dec 14 : Q-band commissioning -- 1 night/week, A-weather, dynamically scheduled. 3 nights max.
• Nov 13 - Dec 1 : Ka-band CCB continuum commissioning and Ka-band Zpectrometer testing -- Sharing four dynamically scheduled, daytime/evening sessions (~noon to ~midnight) for A/B weather. Zpectrometer will have up to ~ 25 hrs, CCB the remaining ~ 15 hrs.
• After Dec. 1 : Ka-band observations can commence, preference given to low-risk continuum projects.
• Week of Dec. 4 : Zpectrometer down, Ku-band up where Zpec was.
• Dec. 11 - Dec. 21 : PTCS OOF Tests -- A-weather, dynamically scheduled, 2 nights max.
• After Dec. 15 : Q-band observations can commence.

Any other Business

-- RichardPrestage - 16 Aug 2006