GBT Operations and Commissioning Meeting 2 April 2004 AGENDA 1. Az Track and Telescope Status -- Bob 2. Observing News -- Ron 3. Scheduling Status -- Carl 4. Frontends, IFs, and Spectral Baselines -- Roger 5. Spectrometer Status -- Rich 6. Software Status -- Mark (for Amy & Nicole) 7. Project Planning Status -- John 8. Any other Business PRELIMINARY REPORTS 1. Az Track and Telescope Status We have received more results from SG&H and are working through them. The replacement plate for splice 45 is in Gadsden. Should be ready for pickup 4/16/04. -- RAA 2. Observing News Over the last two weeks we supported 19 different observing proposals in 30 observing sessions. Projects included two radar observing sessions and 3 VLBI sessions. Eight additional sessions were devoted to program checkouts. The time devoted to tests over the last two weeks was slightly higher than normal, mostly in preparation for the recent release of version 4.2 of M&C. About 280 hours were scheduled for observing, program checkouts or other observing support activities. Approximate lost time during this 280 hours can be categorized as follows: o Subreflector hardware/Telescope Az/El drives: 9 hrs o Dynamic Corrections: may be as high as 7.5 hrs o Snow or (mostly) winds: 5 hrs o Config_tool/Grail: 3.25 hrs o Full Disks, other computing: 2.3 hrs o GFM: 1.75 hrs o Spectrometer/Spectral Processor: 1.5 hrs o M&C Version changes: 1 hr o Converter Rack/new Linux computers: 1 hr o Other Software(GO/IARDS/Active Surface/Ant. Manager/Accessor/DCMON, ...): 2.5 hrs Thus, about 12% of the time set aside for observing was lost. One project, 2A63, which was on the schedule for two sessions of 8 hours each, was completely thwarted by telescope problems. In a typical week, the average amount of time for setting up an observation is about 30 minutes. Probably because of our rash of problems, over the last two weeks setup time averaged to about 45 minutes. Just a reminder that this week we have started using the new method of scheduling support scientist in time blocks instead of scheduling by proposal. -- RJM 3. Scheduling Status Last 2 Weeks ============= Observations for proposals BS131 , GBT04A-041, GBT02A-063, BB178 , GBT02A-031, GBT04A-045, GBT02C-052, GBT02C-030, GBT04A-002, GBT04A-025, GBT03A-002, GBT03B-013, GBT02A-046, GBT04A-026, GBT02A-069, GBT04A-016, GBT02C-012, GBT03B-015, GBT03A-016, GBT03B-019 Completed proposals BS131, BB178, GBT02A-031, GBT02C-052, GBT02C-030, GBT04A-002, GBT03A-002, GBT04A-016 Next Week ========= Observations scheduled for GBT03C-009 [B] PI Jeremy Darling A Direct Measurement of Fine Structure "Constant" Evolution from OH and HI Absorption Lines BW070 PI Craig Walker High Sensitivity Observations of the M84 Jet Base GBT04A-041 PI Jean-Luc Margot The interiors of Mercury and Venus from their spin dynamics GBT02A-063 [P] PI Mark Claussen Water Maser Monitoring of Low and Intermediate Mass Young Stellar Objects GBT04A-003 [B] PI Steve Curran Highly Redshifted HI and OH Absorption in Red Quasars GBT04A-025 PI Harvey Liszt Physical Properties of Halo HI Clouds GBT03A-014 [B] PI Jay Lockman Halo HI Clouds: Distribution and Properties GBT03B-013 [B] PI Min Yun An Unbiased HI Survey of the Coma Cluster and Beyond GBT02C-012 [P] PI Mike Hollis A Search for the First Nucleic Acid Base Biomarker: Interstellar Pyrimidine GBT02A-025 [P] PI Mike Hollis A Search for the Next Interstellar Aldehyde Sugar: Glyceraldehyde GBT03B-015 [B] PI Scott Ransom Timing the Pulsars in the Globular Cluster M30 GBT03A-016 [B] PI Ingrid Stairs The Physics of a Massive Pulsar System GBT02A-028 [P] PI James Braatz Exploring the Radio Spectrum of Orion A and W51 April ===== Scheduled hours [backup] Astronomy ~ 460 [179] Maintenance ~ 8 [141] Tests & Comm ~ 230 [43] Un-assigned ~ 22 May === Scheduled hours [backup] Astronomy ~ 359 [46] Maintenance ~ 88 [61] Tests & Comm ~ 138 [8] Shutdown ~ 26 Un-assigned ~ 133 Proposal Checkouts ================== Awaiting checkout - 0 Active checkout - 19 On Hold - 7 Schedule - 45 Completed - 160 Current backlog [hours] = 2239 -- RCB 4. Frontends, IFs, and Spectral Baselines Baselines: Outfitting of a dewar for baseline testing of Q-band components was completed and initial tests done in the Equipment Room with the Spectrometer. This will continue on maintenance days as the resource schedule allows. The current arrangement consists of a cryogenic LNA with input terminated by a cold waveguide load, the cold mixer, and a room temperature IF amp. We are trying to isolate the causes of rapid spectral changes seen on the GBT. Ka-band and mmConverter: Gain and phase balance between the magic-T's have been adjusted, and preparations for switched noise testing with a lock-in amp is underway. Several tests of the prototype detector amp have been completed, and a test fixture is being completed to allow resolution of some impedance matching issues. Once these are resolved, we should be ready to integrate a detector amp into the receiver. Three more detector amps need to be built for the April telescope tests. M&C receiver manager testing with the hardware occurred this week, and went well, but there may be a few issues to be resolved. A satisfactory 26-40GHz room-temperature amplifier was built using a MMIC chip. The major component development still to be demonstrated is the LO multiplier needed for spectral line tests. Testing of the prototype mmConverter was successfully completed, and construction of the first production unit is underway. There is one issue with a synthesizer sub-harmonic that will require addition of a filter not originally planned. Fab parts for packaging the units are coming out of the shop. For adequate LO drive level we are using commercial MMIC amp chips packaged here in Green Bank. To get proper gain distribution we require both a "two-chip" amp and a "one-chip" amp. First articles of both types have now been designed and built successfully. Other: Three or four engineer-days have been spent looking into the 300kHz spurs seen in spectrometer low-speed sampler data. We believe the source has been isolated to the PCB level, and search for a solution is underway. Cryo maintenance was completed on the C-band system. Thermal cals were done on the K-band receiver at spot frequencies, and the results generally agreed with the Tcal database values. Definition of wiring and M&C manager changes needed for X-band receiver polarization switch addition was developed and documented. -- RDN 4/1/2004 5. Spectrometer Status *****Operation***** Spectrometer operation has been quite smooth in the past few weeks. Some enhancements to software have greatly reduced the occurrence of serial and DMA Interrupt errors. Recovery from DMA Interupt errors usually takes only starting a new scan. *****Development***** These two weeks have been working on LTA schematic design, include build some components that not in the library. The design of the noise source for the Cross-Correlation Test Fixture was completed. Work has started on the regulator board and filters required for this unit. With some input from Ray, the test procedure for the spigot cards in the system was completed and tested. Some work has been done by Ray and Rich towards getting "true" 200 MHz spigot modes. Modifications to the firmware in the Correlator Control Card are complete and have been bench tested. New personalities for the memory boards have been bench tested, but they don't appear to be working correctly as of now. *****Plans***** Continue development of LTA replacement, Cross-Correlation Test Fixture and 200 MHz spigot modes. -- Rich and Holly 6. Software Status Single Dish Development IPT #75 - Friday, April 2, 2004 Today ends week 1 of 6 in development cycle C3 in 2004. The Plan of Record is available from the wiki at Software.PlanOfRecordC32004. M&C v4.2 was released on Wednesday, March 31. Release notes for this version can be found on the wiki at Software.ReleaseNotes_4_2. Release documentation for our latest release and other previous cycles can be found at Software.SoftwareReportCentral on the wiki. Just a reminder that because of the port of the Analog Filter Rack and the Converter Rack, gbteio1 and gbteio2 are no more. Last week (week 6 of cycle C2 in 2004), was spent mainly on testing - both regression and integration. Three staff members were away at conferences. This week, we hosted and presented a series of talks for our colleagues from other NRAO sites. These talks were part of an e2e architecture meeting, which was productive and generated many useful comments and suggestions. A schedule for the meeting can be found on the wiki at Software.SoftwareSpecialTopicMar04 along with a few of the presentations. Coding has started on the CCB Manager. This project spans two development cycles - C2 and C3. The work this cycle continues from the groundwork laid last cycle. Ka Band support work continues this cycle. IF path routing is complete and the receiver setup is almost complete. We will have a staff member available throughout Ka band testing to address and resolve (if possible) any issues that may be found. PTCS work this week involved delivering a glish client to Dana Balser for testing. This client will be used to compare refraction algorithms. -- AS 7. Project Planning Status March 29, 2004 Planning Meeting Minutes Rm 137 10:45 A.M. [0] Observer comments & operator log items to discuss Operator's log comments Significant failures this week stemmed from: Computing: Disks filled up on GBT partitions (~1.5 hrs lost) Chris has added this partition to that that is automatically checked. Software: GFM, Grail, Go , IF Manager, wrong versions, Converter rack, Scylla CPU suckage, dcmon sucking up all of victor's CPU Electronics: Spectrometer -- Data Interrupt Failure, setup failures, hung in stopping A considerable amount of effort was put on the data interrupt failure problem this last week, and the problem was identified. Work is underway to fix it. C band receiver cryogenics -- First cooldown failed, second one succeeded. Telescope/Servo: Elevation motor #3 Subreflector actuator limit switch wiring (7 hrs) Observing Summaries F. Ghigo: VLBI Project BB178 Succesful. High winds during ~2 hrs. T. Minter: K. O'Neil: Project: 4A-16, J. Donovan, F. Camilo PF800, Spigot & BCPM Problem summary: (1) Scylla Xsun process (run by root) slowly took over all CPU for no apparent reason Obs. Summary: The project had a rough start, but once up and running (about 6:00 pm) things went very smoothly, and both the spigot and bcpm worked great. G. Langston: Project : GBT04A-045, Mallory Roberts (remotely) BCPM Observations Obs Summary: Observations were successful. Problem Summary: Go did not work to start the BCPM manager [1] Resource calendar schedule conflicts and discussions No conflicts as of today. [2] Observing Schedule discussions There is a serious shortage of low frequency proposals in the backlog. Several items were identified that might help matters, including fixing the spectrometer data interrupt failure bug and the 300 KHz spurs in the IF system. We will be working through this over the next couple of weeks. The electrical shutdown in CV may cause us internet connectivity problems. Carl will make sure that the computing staffs from the 2 sites can have a plan together so that our connectivity is maintained, either via generators or via re-routing our traffic through the AOC. We need to make sure that this is tested beforehand. [3] GBT development planning Need to fix the Control library problem that causes the data interrupt failures. [4] AOB It was mentioned that there needs to be better communication between operations and the SDD on changes to the system. Several suggestions were made, with the bottom line being that the SDD should send out detailed emails to gbtlocal when any changes are made in the system. These mails should allow the operations staff and observing friends to know what action, if any, they need to take. -- JMF 8. Any other Business