GBT Commissioning and Operations Meeting 01 August 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 -- Nicole 6. Schedule -- Carl 7. Project scheduling -- John 8. Any other business Preliminary Reports 1. Az Track Status No major developments or milestones reached. Two splices were reshimmed this week. Dennis and Bob researched material properties and considerations for a new design. Lee has asked Simpson, Gumpertz, and Heger for an estimate for Phase 2 analysis based on criteria discussed last week. --- BA 2. Observing news A number of problems were encountered with the Heiles et al observations over the weekend, as reported under the "Project Scheduling" section. Most, if not all of these have now been addressed, and the last two nights have proceeded pretty smoothly. It seems like most of the Spectral Processor problems were a by-product of network congestion, in turn due to the removal of the PF1 and PF2 hardware. VLBI experiments ran very smoothly. Problems with missing sources were due to poor schedule construction, not because the GBT slew speeds were incorrect. Frank requested that extending the phase cals up to Q-band be added as a request for project work. --- RMP 3. Spectrometer status The spectrometer saw very little use this week. No problems were reported. Development Progress: Continue working on LTA 32 MHZ upgrading. After yesterdays meeting, made a little progress. It turns out that two Adder Xilinx chip on LTA board are slightly slower than some of others. I replaced these two chips on the LTA with others, It passed self test E, which is complete self test. I am going to talk with Ray about it. hopefully, make some change in Adder FPGA design could fix this problem. Time was spent characterizing the time it takes for the different microprocessors in the system to execute their reset routines. This will be needed in the code that implements the hardware reset. The pulsar spigot card's reset time was much longer than the rest. I have sent a request to Ray to explain the purpose of certain delays in the code. Work has begun on a software requirements document for the pulsar modes of the spectrometer. Some time has been spent reviewing the status of the pulsar spigot and planning some tests before the telescope runs in mid-August. Troubleshooting: Some time was spent on the "other" spectrometer (Spectral Processor) trying to get it to fail like it did last weekend. The two data acquisition cards in gemini were swapped to see if the problem would migrate from rack B to rack A. Instead, it ran error-free every day this week. The logs for this device contain much less information that those for the spectrometer. Should we consider upgrading these to make troubleshooting easier??? [Now believed to be primarily related to the network problems, RMP] Plans for next week: - Continue work on the LTA 32 MHz upgrade. In particular, we will try to gain an understanding of why some Xilinx chips work with the faster microprocessors and why some don't. We will probably put a few upgraded ones in the system to see how they do. - Finish characterizing the reset times of the system microprocessor and generate an MR to the software development group requesting that the spectrometer code be modified to take advantage of the new capability. - Continue working on software requirements for pulsar modes. --- RL & HC 4. Spectral Baseline, Front-end, and IF work One of a mixer for possible use in the Converter Module upconverter spot has been evaluated. Bench testing of the mixer this week showed that, compared with the mixer type currently used, the I-L and L-I isolation is much higher (better) at the lower half of 1-8 GHz, but lower (worse) at 6 and 8GHz. Testing with the network analyzer failed to detect any gain ripple sensitivity to the LO2 cable length with the new mixer type (definitely not the case with the older type) in the 1-2 GHz range. While this increased our confidence that we understand the effect, the poorer isolation at the upper frequency range means that changing the mixer is not a good solution. So, we will continue to pursue the option of using a LO2 buffer amp right at the mixer LO port. Drawings for a housing for a MMIC amplifier chip were completed and submitted to the shop this week. Because of shop load, it will be at least three weeks before work on the housing will start. The K-band upgrade proceeds. This week Mike did s-parameter measurements on the thermal transitions. Some small, broad, ripple features were seen near midband in the insertion loss of two of the transitions; one low band and one high band unit. Narrow features were seen above about 25.8GHz in both high band units, perhaps indicating a moding problem, although at this time we cannot be sure the features are not in test transitions to rectangular waveguide. These tests do add motivation to pursue better thermal gap designs. Construction of the 1cm receiver is ramping back up. Galen has essentially finished the dewar shell design, is proceeding with the cal logic circuits and other issues, and has Bill Bennett wiring the receiver card cage. Rohit and Galen are working to complete the channelization multiplexer design and construction started by visitor Brian Thomas. This receiver project also is loading up the machine shop. Four of the existing IF fiber modulators were pulled this week to be replaced with the new ripple compensated units. The feed defroster was also pulled down for an effort to improve it's effectiveness. And, the indoor antenna range is nearing operational status. Next week a training class in operation of the range software will be given by the vendor. --- RDN 5. Software status Single Dish Development IPT #45 - Friday, August 1, 2003 We are now ending week 5 of a 7 week development cycle, meaning the development cycle is two thirds of the way over. The next upcoming release of M&Cv3.16 is planned for immediately after the summer school, on or about 8/18/03. The Plan of Record for the current development cycle is available from the Project Office web site at http://tryllium.gb.nrao.edu/docs/POR/POR_July03.pdf. Activities for next cycle will include continued work on Data Export and Accessibility, the Ease of Use Initiative, PTCS activities, completion of the current phase for the Antenna Test Range software, and other continuing maintenance and enhancement activities including the addition of a new quicktest for the spectrometer. The Project Charter for DCR Improvements has been successfully completed, and will be awaiting review by the sponsor, after which Ray will be giving a presentation on the Charter results immediately following the summer school. Several small-scale DCR issues were solved in the process of compiling the Charter, and these will be fully tested prior to release in mid-August. The 5000 samples per scan limitation on the DCR has been resolved, tested internally, and is currently undergoing sponsor testing. The issue with the DCR starting one second late has been resolved in development and is awaiting further internal testing. The new spectrometer quicktest has been developed, internal tested, and now waiting to be sponsor tested. Throughout the summer the possibility of compiling a single SDFITS file for GBT data is being explored in depth. SDFITS files have already been constructed for several DCR and spectrometer data sets, and have received preliminary evaluation by astronomers. By the end of the development cycle the goal is to have a memo in place that discusses the specifications for these prototypes, so that this can be reviewed by a wider audience as we decide whether to make this a production capability. Work is underway, and we anticipate meeting the deadline. On Thursday, summer student Andy Cowan gave a presentation on the feasibility study that he performed this summer in this area. Dave Fleming will be responsible for leading the transition from the project's present state to production state over the next few cycles. -NMR 6. Schedule Last week ======= Observations for: GBT01A-007, GBT02C-013, GBT02C-009, GBT02C-034, GBT03B-015, BF073 Completed: GBT02C-034 August ===== Scheduled hours: Astronomy - 342 Maintenance - 193 Tests & Commissioning - 197 Un-assigned - 12 September ======== Scheduled hours: Astronomy - 217 [ backup 78] Maintenance - 147 [backup 48] Tests & Commissioning - 240 [backup 7] Un-assigned - 117 --- CB 7. Project scheduling July 28th Planning Meeting Minutes Rm 241 10:00 A.M. 0) Observer comments David Nice, GBT02C-060 Summary: :( "These observations better described as \"marginally productive\" rather than \"complete failure\". Observations were severely affected by broadband RFI (see RFI section below, and attachment a.ps). In fact, the RFI was sufficiently bad on the second day of observations that we gave up collecting low frequency data after a few hours." Karen O'Neil's report on 01A-7, 02C-10, 02C-13, 02C-9: Summary: :( and :) (1) Difficulties in setting up the GO tables + glish observing scripts to perform the desired observations (2) Spectral Processor errors - difficulty in dumping memory/clearing drawer B (3) Cleo/M&C failing to accurately reflect the state of the system (4) Problems with receiving adequate power through the C-Band receiver (5) Failures in running identical GO commands with the L-band receiver Friday and Saturday and the C-band receiver on Sunday. (6) Scan coordinator aborting scans but not stopping the observations (7) Timing on the optical drivers is off They did, however, collect good data when not wrestling with the system. 1) This week's schedule Maintenance days are cut short Wednesday and Thursday. PTCS temperature sensor installation. PTCS request for trilateration time (03:30-07:00 Thursday?) (2:00-0930 Sunday August 3rd?) 2) Next week's schedule No discussions 3) August Observing Schedule discussions PTCS requests 4 hrs on 8/8 and 8/16. Richard will attempt to trade some hours around with observers to get daytime test time. 4) September Observing Schedule discussions Added time for PTCS and Baseline tests to the schedule 5) GBT development planning Project Management 6 weeks review meeting set for Monday, August 4, 1:30-4:30) Strategic plan discussion 6) AOB --- JF 8. Any other business Kim Constantikes gave an update on the antenna temperature sensor project. All sensors (apart from two on the horizontal feed-arm, which will be postponed) are now installed and working. The data are available to observers now if they wish through the Archivist, but the full commissioning of the system for production use will take a couple of months. Kim showed some interesting early results from the first few days of operation. Richard Prestage 01 August 2003