GBT Operations & Commissioning Meeting 16 July 2004 AGENDA 1. Az track, antenna Report -- Bob 2. Observing News -- Ron 3. Frontends, IFs, and Spectral Baselines -- Roger 4. Spectrometer Status -- Rich 5. Software Status -- Nicole 6. Project Planning Status -- Phil (for John) 7. Any other Business REPORTS 1. Az track, antenna Report We received the results of the metallurgy tests of trial plate 45 just before the July 4 holiday: * All of the mechanical properties were consistent with good commercial grade AISI 4140. * Metallographic examination did not reveal any defects where Ultrasonic examination indicated. * A heat affected zone, caused by high heat input after quenching and tempering, was identified at the top surface, and extending a 1/2" into the plate. The material was subsequently softer below the surface. The existence of a heat affected zone was suspected to be caused by the use of flame straightening equipment to meet flatness specifications. Gadsden Tool investigated and confirmed this. The first batch of 10 plates had 4 plates that were very badly bowed during the quenching and tempering steps. Subsequent attention to detail eliminated recurrence on following orders. 3 of the 4 that were badly bowed were likely used to make plate 45 and the two small transition plates. The location of the 4th plate is to be determined. The new trial plate 45 was examined Monday by UT and found to be without defect. The remains of the original trial plate 45 were re-examined, and a flaw in technique was found that caused the erroneous indications. The plate is defect free. Other news: * The elevation shaft repairs were also checked by UT and found free of defects. * Work continues on changing the seals and oil in the azimuth bearings. This work will continue into October. * Work also continues on the motor blower intakes. The sheet metal has been all cut to shape and is being assembled and installed. * The structural inspection continues, with the use of the long manlift now. No significant defects have been found this week. -- RAA 2. Observing News Over the last week we supported six observing projects in twelve observing sessions, not including two sessions in which the Charlottesville summer students used the GBT. We had three sessions of API software tests. In all, we had ~95 hours scheduled for astronomy and ~15 for tests. Lost time this week was again under 5%. The main trouble this week was with the servo software (three hours lost) -- Joe implemented a patch which seems to have fixed the problem. Difficulties with the Spigot cost observers almost two hours. The network was also down for 30 minutes but we didn't suffer any lost time since the problem were concurrent with other difficulties. And, 30 minutes were lost to the Spectral Processor. I anticipate next week will be about the same since the number and difficulty of the projects are about the same as this week's projects. -- RJM 3. Frontends, IFs, and Spectral Baselines Operational issues: No new operational issues this week. Baselines: The demo 4-way power splitter we evaluated in OR1 unfortunately performed similar to the units currently in the system. The insertion delay of both splitter designs change rapidly with temperature near the operating temperature. This is probably associated with teflon's material phase transition near 20C. I have been able to make a simple analytical model of the power splitter interaction with reflections at its input and output ports which shows qualitatively how change in insertion delay changes the gain ripple, and have observed the effect on a simple hardware mockup with the VNA. I am now considering mitigation by running the splitter at an elevated temperature with a secondary temperature control loop. Q-band: Work continues on the Q-band receiver. Gary and Jonah have located a low-level instability (oscillation) related to interaction between the cooled mixers and the IF amplifiers. This problem is being investigated. Ka-band/mmConverter: Wiring of the five mmConverter modules and the power supply/LO chassis is completed. The only bit of hardware now missing is the MCB digital interface. The receiver is going back together. X-band: The X-band receiver is in the lab. A polarization switch will be installed, and the RF and LO filters changed to accomodate special observations at 11.1 GHz. The required mods to the RF plate have been scoped out, and cardcage wiring changes are underway. R. Norrod 7/16/2004 4. Spectrometer Status 5. Software Status Single Dish Development IPT #89 - Friday, July 16, 2004 This is week 3 of 6 in the fifth development cycle (C5) in 2004. The Plan of Record is available from the wiki at Software.PlanOfRecordC52004. Post-beta Observing API tests continued this week. The development group has written an observing script for Dana, which is being used for PTCS tests and doubling as a test vehicle for the Observing API. Details on the Observing API, including its usage, can be found on the wiki at Data.ObservingAPIBeta. Contact Amy Shelton if you would like an overview of the documentation and the Observing API or have any questions. Jim is nearly complete with the first data reduction case description, for total power position switched single beam data. The first case represents an important achievement; later cases will go much more quickly once the design and general idea are laid out. The first draft of the compendium of cases should be available at the end of C5. Bob and Dave have also continued discussing the design for the first release of IDL modules. In other news, work has continued on MRs for PTCS this week in advance of development. Circular emulation for PF1 was backwards, and this has been fixed, but the fix uncovered another issue with PF1 which is being resolved. In order to create a FITS file for the Ka band receiver, the receivers must be ported, so effort has gone into scoping this out and development is targeted for the week of August 9th. Operational Support: + None significant. -- NMR 6. Project Planning Status July 12, 2004 Planning Meeting Minutes Rm 137 10:45 A.M. [0] Observer comments & operator log items resulting in lost time: Operator's log comments Significant failures this week stemmed from: Computing: Prospero crash Chris Clark reports that a tape drive malfunction caused this crash. The tape drives have been removed from Prospero for the time being. Software: Spectral Processor, BCPM, antenna control problems Amy reports that Joe has patched the antenna control software to fix the problems that plagued us over the weekend. Electronics: S band refrigerator Phil suggested that we should be developing a preventive maintenance schedule for changing out refrigerators before they fail in an inopportune moment. RFI @ L band The RFI reported at L band is the DME, Bedford Radar, and other well-known sources. The observers were using an 800 MHz bandpass, which admits all these troublesome frequencies. The dynamic range of the system is not sufficient to prevent saturation of the IF with this much RFI in the band. Telescope/Servo: Supposed servo problems were software. Other Problems from Observing Reports: Jay Lockman: 04B_001 Optical drivers not properly configured SP integration time not set correctly from GO Both known problems. T. Minter: 4B-035, 4B-005 Config tool segfault [1] Resource calendar schedule conflicts and discussions Az bearing seal PM vs inspections. Harry Morton is in charge of both items, so we assume he can negotiate with himself on it. [2] Observing Schedule discussions PTCS time Tuesday Amy and Dana will do tests from 7 P.M. to 11:00. Then, program 4B5 will run from 11 to 7:00 A.M. Tuesday. Spigot data offload time There is concern that the spigot data offload during maintenance will affect the ability of Electronics to do testing and debugging of the spigot modes, since the machine is tied up. [3] GBT development planning Spigot software development discussion It was agreed that when Scott Ransom comes on board, he will be asked to outline a plan in conjunction with Karen O'neil and SDD. It was further agreed that there is no spare software resources that can be brought to bear on this right now. Ron suggested building a GUI to run the scripts in the proper sequence, and that would allow the users to be insulated a bit from the complexities of setup. Jay provided many comments and suggestions on the GBT software suite. Frank, as Project Scientist for the ease of use program, will examine Jay's comments and suggestions and evaluate whether or not the current plan covers them, and if not, whether to modify the plan. It seemed to us that much of the desires were in the plan, but we think Frank should make the final determination. Spectrometer bad lags fixes Amy will check the availability of SDD resources to work on the 2 patches suggested by John in last week's email exchange. It is unclear if the parallel reading patch is really ready or not. Joe will be consulted on that. [4] AOB None. -- JMF 7. Any other Business