GBT Operations & Commissioning Meeting 03 September 2004 AGENDA 1. Az track, antenna Report -- Bob 2. Observing News -- Glen 3. Scheduling Status -- Carl 4. Frontends, IFs, and Spectral Baselines -- Roger 5. Spectrometer Status -- Rich 6. Software Status -- Amy 7. Project Planning Status -- John 8. Any other Business REPORTS 1. Az track, Antenna Report * We replaced plate 21 with one made from AISI 4340 material. So far, it is performing well. * We have received some results from SGH's runs of the wheel and patch loads, and they are under review and discussion with SGH. * No results yet on original plate metallurgy. Other news: * Only 4 azimuth bearings remain to be converted from grease to oil. * Twelve azimuth motor blower intakes remain to be modified. All of the elevation drives have been modified. -- RAA 2. Observing News Observing News, August 27 to September 2 Since last Thursday, we supported five observing proposals, in eleven observing sessions. We had 71 hours of Astronomy (79 if GG057 is counted as Astronomy), and 18 hours of X and PF2 Receiver Checkout. We had four 12 hour maintenance days. The Cassini/Huygens VLBI tests appears to have gone very smoothly using Mark 5 (disk based) recorders. The X band circular polarization purity seems good, showing 23 dB of isolation between polarizations (http://www.gb.nrao.edu/~glangsto/cassini) The X band polarization tests of Heiles and Robishaw also appear to have gone smoothly. The setup was well documented and their IDL scripts for real-time SP data display worked fine for 15 hours straight. Note that Robishaw and Heiles do not use the noise diode during observations so should not have significant problems due to the noise diode baseline ripple. Most observing setup seems to have gone smoothly. Very small amounts of lost time due to a variety of problems. "Sources not up" cost 1.25 hours; 15 minutes lost due to Spectral Processor hangs in "running". Five minutes lost due to Dynamic corrections software problems and Twenty minutes lost due to a spectrometer manager software hang/reboot. Ten minutes lost due to DCR and 10 to ACU manager software. -- GL 3. Scheduling Status Last Week ========= Observations for proposals GBT02A-021, GBT02A-046, GBT02A-003, GBT04B-037, GBT02A-028 Completed proposals GBT02A-021, GBT02A-046 Next Week ========= Observations scheduled for GBT03C-009 PI Jeremy Darling A Direct Measurement of Fine Structure "Constant" Evolution from OH and HI Absorption Lines GBT04A-030 PI Ingrid Stairs High-Precison Timing of Binary Pulsars at the GBT GBT04B-020 PI Liz Humphreys Search for Water Megamasers Through Gravitational Lenses BT075 PI Andrea Tarchi 3C403: Is the water maser in an FRII associated with an accretion disk or is due to a jet interaction? GBT04A-003 PI Steve Curran Highly Redshifted HI and OH Absorption in Red Quasars GBT04B-037 [B] PI Scott Ransom A Pilot 350MHz Survey for Fast Pulsars GBT02A-003 PI Jeremy Darling Do Hyperluminous IR Galaxies Produce OH Gigamasers? GBT02C-002 PI Christopher Carilli Redshifted HI 21cm Absorption towards Red Gravitational Lenses (J0134-0931, J1004+1229) GBT04B-029 PI Ingrid Stairs Timing New Binary and Millisecond Pulsars from the Parkes Multibeam Survey GBT04C-018 [B] PI Alberto Bolatto A Search for Cosmological HI Absorption Systems Toward Radio Selected Flat-Spectrum Sources GBT01A-029 [P] PI Steve Eales A First Investigation of the Origin of Galaxies with the GBT Scheduled hours [backup] ======================== Category/Month-> September October November December Astronomy ~ 351 [179] 328 [099] 425 [140] 404 [019] Maintenance ~ 210 91 [051] 21 [077] 28 [077] Test & Comm ~ 154 [053] 272 [020] 212 [026] 131 [006] Shutdown ~ 0 0 36 36 Un-assigned ~ 5 54 27 146 Proposal Checkouts ================== Awaiting checkout - 0 Active checkout - 19 On Hold - 5 Schedule - 69 Completed - 215 Current backlog [hours prior to 04B*] = 1165 Total time to discharge [hours] = 2930 * Includes projects that are on hold for trimester 04B -- RCB 4. Frontends, IFs, and Spectral Baselines Operational issues: PF2 was installed - no problems encountered. The defective filterbank in PF1 is being repaired. A ~20MHz ripple in the X-band receiver Tcal was identified and corrected. Baselines: No work this week. Q-band: Gary and Jonah are in the process of making detailed gain/noise measurements of the mixer. No results to report. Progress has been slowed due to PF and antenna range work. Ka Receiver: The dewar is reassembled and cooled, 15K stage is at 12.6K, the feed horns are at 63K and gradually getting colder. The warm section of the differencing assembly with the spectral down conversion mixers, LO multipliers and video amps for continuum will be attached to the receiver today or Friday, after which the phase and amplitude of the differencing assemblies for both beams will be balanced. Testing of stability, receiver temperature in the four continuum sub-bands and software will start on Tuesday. -- GW Other: The Penn Array RFI box drawings did not get sent out for review, because Jeff Cromer was needed on another job, and did not complete the details. -- R. Norrod 9/2/2004 5. Spectrometer Status Spectrometer Report 26 August - 2 September 2004 *****Operations***** It has been another quiet week for the spectrometer. There was no significant time lost due to either hardware or software. *****Development***** LTA replacement: Work on LTA PCB design is continuing. 40% finished. Spigot Mode Testing: Karen checked out a number of new modes for the spigot computer, including a few 2-bit modes and single-polarization 2-bit modes. The goal in getting these modes working is to eventually provide us with 2-bit separate-polarization modes and, eventually, cross-polarization modes. A few minor bugs were encountered with the modes, but those should be resolved w/i the week and the modes could then be released for use. Karen also checked out two issues reported by Scott Ransom during the last two weeks of spigot observations. The first issue is the reliability of the spigot2 computer in taking data while other non-disk-intensive processes were going on. The system appeared to work as always, once the disk dameons were turned off (a procedure which is now part of regular spigot operation), indicating that no new problems with the computer have appeared. Karen also checked out the reported high noise levels for some of the released spigot modes which Scott Ransom reported (e.g. with mode 56). While we do not yet have a definitive answer to this question, it appears as if the noise is coming from the 1.32ms pulsar of the spectrometer. However, at this point we are not sure exactly how much this pulse is in fact affecting the data, as it does not seem to always be present. A further look at the data is underway. Cross-Correlation Test Fixture: The filter board was received from the manufacturer. Incoming inspection revealed one problem: two critical line widths were off by a factor of two in one of the microstrip filters. We have not received much sympathy from the manufacturer. Simulations show that the filter should still work well enough for our purposes. The design of the combining and output module was started this week. Component selection is about 50 % complete. Spigot Timing: We are still trying to understand the timing delay of the spigot system. Last week I reported finding 1.25 msec of the missing delay. This week Ray looked at delays from the design point of view. He can account for a delay of approx. 1.5 * 1.3 msec from the spectrometer input to the spigot card input. Spigot true-200 MHz modes: Ray was successful in designing Xilinx personalities for these modes. Both the prompt and delayed outputs of the memory board look correct. Also reports of other Xilinx personalities having problems were erroneous; it turned out that the logic analyzer needed a better ground! *****Plans***** - Continue LTA replacement and Cross-Correlation Text Fixture development. - Test true 200 MHz modes using the spectrometer on Thursday and Friday. Ray will be here for this. -- Rich, Karen and Holly 6. Software Status Single Dish Development IPT #96 - Friday, September 3, 2004 This is week 3 of 6 in the sixth development cycle (C6) in 2004. The Plan of Record is available from the wiki at Software.PlanOfRecordC62004. The Software Review occurred on Monday, August 30. Those who missed the review are encouraged to visit Software.ReviewAgenda on the wiki. The wiki page contains all the presentations which were given. Overall, we believe that the review went very well and we received many useful comments from the reviewers. Development of Ka Band software, Spectrometer/Spigot fixes, and the porting of the rest of the receiver managers to Linux continued this week. The Ka Manager is now a synchronous manager which write FITS files. Melinda attended a meeting last week at Goddard to discuss/coordinate the software for the Penn Array. The changes to the Spectrometer data pipeline are currently being tested and look promising. Joe and Mark were able to run the Spectrometer with dump times of 400 ms and data was buffered properly and written to disk. They are still looking into the problems reported with aborting. In support of PTCS activities, Paul worked on Model 4A. Work continues to address monitoring issues found with sampler2log on wind. Operational support was light this week. -- AS 7. Project Planning Status The Project Coordination meeting was not held last Monday owing to the software review. Notes from last week's logs follow: NOTES ON LAST WEEK. NO MEETING WILL BE HELD!!! August 30, 2004 Planning Meeting Rm 137 10:45 A.M. [0] Observer comments & operator log items resulting in lost time: Observer's comments: Operator's log comments Significant failures the past 2 weeks stemmed from: Computing: Prospero failed Software: Spectral Processor hung in stopping, spurious messages from muacu Electronics: Spectrometer setup failures, X band receiver ripple? Telescope/Servo: Turret unresponsive to commands from OCT or M&C EL motor #3 making noise Other Problems from Observing Reports: None. [1] Resource calendar schedule conflicts and discussions [2] Observing Schedule discussions [3] GBT development planning [4] AOB 8. Any other Business