GBT Commissioning and Operations Meeting 11 July 2003 AGENDA 1. Az Track Status -- Bob A. 2. Observing news -- Ron 3. Spectrometer status -- Rich 4. Spectral Baseline, Front-end, and IF work -- Roger 5. Software status -- Amy 6. Project scheduling -- John 7. Any other business Preliminary Reports 1. Az Track Status Update on Azimuth Track effort: * Initial review of pre and post data show a reduction of baseplate deflections by about half.  This is encouraging.  Peak to Peak wheel tilt is about 0.070 degrees.  This is also good.  The questions to be answered are: is this enough improvement,  and is it stable. * Expecting additional metallurgical info on wear plates this coming week. Telescope Operations: * Analyses of the grease in the azimuth wheel bearings has shown oxidation and wear particles.  Consultations with both bearing manufacturers and ExxonMobil have brought a recommendation to change from the grease used to an ultra high viscosity oil.  A trial conversion was made this week.  Oil requires a change in seal configuration, and we have had mixed success with that.  More effort will be needed to get to a point where we can say whether this is an improvement. * Preparations underway to support the Structural Inspection.  This will have significant impacts on other efforts as well as routine activities. -- RA 2. Observing news This report covers the last two weeks of observing. Most of the lost time during that period were from four sources, of which the last seems to be new and is the most troublesome. o DMA Spectrometer failures, which only last about ten minutes and which affected Doug Roberts and Deidre Hunter's observing. o RFI made Michael Nord's observing at 300 MHz somewhat challenging. o Winds o Spectral Processor failures which affected everyone who tried using the device. Most had only short failures but David Nice and Ingid Stairs lost 1 and 2.5 hours, respectively, to SP failures. Other news is: o I had a somewhat productive holography run last Wednesday. The good news is that the holography receiver, even on the strongest satellites, no longer seems to be in compression. Unfortunately, there's strong evidence that the current antenna trajectory algorithm isn't good enough for the holography experiment. And, we either have a hardware of software problem that didn't exist in May but which drops phase measurements for a second every few seconds. If time allows, I can present some of the holography data. o Sunday night, the C'Ville and GB students who will be participating in the single dish school in August had their 'hand' on' observing session. o Farhad Yussefzadeh et al's galactic center mapping project has produced some outstanding images of the Galactic Center. And Dave Thilker et al's have submitted an ApJ Letter on their HI map of the Andromeda Galaxy. Again, if time allows, I might have a little show-and-tell. -- RJM 3. Spectrometer status - Spigot: Kaplan has had success setting gains and offset in 16-bit mode. Some problems he had led to firware changes which are installed but not tested. The next step is to calibrate at 16-bits, set gains and offsets, and try to observe at 8, 4, and 2-bits. David will not be available the next few weeks. Another firmware upgrade was installed and tested; it has to do with improving the reliability of the communications with the spigot card. - High Speed Samplers: Work is on-going to improve the purity of the sampling clock and reduce the RFI from the samplers. A test procedure is in development. One unit, in addition to the initial prototype done last year, has been modified and tested. A few new problems were encountered and solved. - Work has continued on trying to solve the DMA error problem and to get the LTA microprocessors to operate at 32 MHz. - Minter encountered a failure on the spectrometer last weekend which resulted in a 100 MHz comb in the 800 MHz bandpass. My best guess is that it was cause by something analogous to the paddle-board problem. The sampler to backplane interface is tin/gold, just like the paddle-board to backplane interface. Merely unplugging the sampler and plugging it back in fixed the problem. This could be the start of something bad... -- Rich 4. Spectral Baseline, Front-end, and IF work No significant new baseline observations were made this week. Galen has ordered phase-stable coax cables for the Optical Receiver to Converter Module connections. He also is designing a package for a prototype LO2 buffer amp. The shop is well along on fabrication of the Ku-band waffle-iron thermal transition. PF2 was first installed this week for commissioning. Engineering checks show Tsys at about 24K at access elevation, and the stability seems reasonable. There is lots of RFI in the passband though. Spectrometer scans were taken and the results will be distributed in a separate document. Several software details need to be taken care of before the receiver is useful for astronomical observations. Fisher, Balser, and Norrod completed draft contributions to the planned baseline internal report. Rick has integrated the contributions and editing is underway. RDN 7/10/03 5. Software status We are ending week 5 of a 5-week development cycle, which was supposed to culminate in the release of M&Cv3.15 on 7/9/03. Release notes were distributed to the gbt e-mail list and are also available at http://tryllium.gb.nrao.edu/release. However, the release did not go as planned due to a variety of problems. Jay Lockman has graciously agreed to give the SDD the first two hours of his run on Tuesday, July 15 for the release of v3.15. In order to prevent further disaster and to make optimum use of our new release time, we will be using the equivalent of a full maintenance day (Monday and Tuesday) for testing of v3.15 with the antenna simulator prior to the new release date and time. The Plan of Record for the next development cycle will be available in the next few days from the Project Office web site. Activities for next cycle will include continued work on Data Export and Accessibility, the Ease of Use Initiative, PTCS activities, the Antenna Test Range software, and other continuing maintenance and enhancement activities. Also included next cycle is the creation of a maintenance plan; such a plan will include a formal release process that will be aimed at eliminating our continued release problems. The design review, held Monday 6/30, for the Antenna Test Range Phase went as planned. Michael Lacasse is currently working of Phase 1 of the Project Charter. A significant amount of time this week has been spent on operational support, particularly in support of the Active Surface power down procedure and the Prime Focus 2 receiver. --- AS 6. Project scheduling July 7th Planning Meeting Rm 241 10:00 A.M. 0) Observer comments No formal comments. We discussed recent problems with the Spectral Processor; these were unfortunate, but do not appear to be part of a new systemic problem. 1) This week's schedule Walkthrough will be brought one hour early on Wednesday to accomodate M&C moving telescope time request. 2) Next week's schedule No obvious problems at this time. 3) July Observing Schedule discussions Bob noted structual inspections will commence 7:30am July 21st. This will require the antenna to remain at access or other specific locations for almost all maintenance time. This will conflict with a hoped for 6 hour slot for the EMS trilateration experiment at the end of July (this was originally planned for 16th July, but has slipped). Richard will explore potential options for this with Carl. 4) August Observing Schedule discussions Kaplan has requested August 22,23,24; to be confirmed by Carl on his return. 5) GBT development process and program proposal review Need to get input from Brian Mason on his projects. Ford has put in information from Norrod on his projects. Karen's spectrometer project planning is gaining steam, but lacks finishing. An extremely productive Penn Array Progress Meeting was held last week, A Caltech Continuum Backend telecon was scheduled for Monday 7th 6) AOB Initial holography tests with repaired receiver appear much more successful. As well as the HVAC, it appears that the active surface electronics is generating RFI visible at 340MHz. In the near term, the solution will simply be to turn the electronics off, Operators have instructions as to how to do this. -- RMP 7. Any other business None. R. Prestage 2003 July 15