GBT Operations and Commissioning Meeting 10 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 Az Track * SGH has a 3D model of a wheel on a wear plate running. It has been running for 6 days on a 3.8GHz processor, and they expect it to finish this weekend. Results of the modifications done to the 2D model looked encouraging - showing the deformation effect we expected in the rolling direction. Encouraging, but we aren't through yet. * We received a report on the metallurgical tests late Thursday afternoon, and we are still reviewing those results. * The method used to machine the 4340 plates did not leave enough of a coupon for tensile or charpy testing. We will be able to check the hardness vs. depth and chemistry, though. Plate 21 of the 4340 material continues to do well. -- RAA 2. Observing News Observing News, September 3 to September 9 Since last Thursday, we supported thirteen observing proposals, in nineteen observing sessions. We had 94 hours of Astronomy. PF1 Receiver Checkout took 3 hours and PTCS ran for 19 hours. We had three 12 hour maintenance days. Most setups took less than 1 hour. Most observing setups seems to have gone smoothly. Nagging problems with a few bad lags in a few integrations of spectrometer have made data reduction more difficult. Wes and Jeff are looking into RFI reported by Jeremy Darling. Improvements in config_tool resulted in some new confusion for observers switching between spectra and pointing modes, but work-around is well understood. PTCS reported some sub-reflector servo problems, which appear to have been fixed. Small amounts of time lost due to miscellaneous problems. Some antenna azimuth break faults caused small loses of time until, Monday, when the fault would not clear. Tim and Bob came in to checkout the problem. Computer network problems caused 1:22 minutes of lost pulsar observations. GL 3. Scheduling Status Last Week ========= Observations for proposals GBT03C-009, GBT04A-030, GBT04B-020, BT075 , GBT04A-003, GBT04B-037, GBT02A-069, GBT02A-003, GBT02C-002, GBT04B-039, GBT04B-029, GBT04C-018 Completed proposals GBT03C-009, GBT04B-020, GBT02A-003, GBT02C-002, GBT04B-039 Next Week ========= Observations scheduled for GBT04B-021 [P] PI Thomas Troland The 13 GHz SO Zeeman effect in an outflow region GBT04A-045 PI Mallory Roberts Timing of Three Binary Pulsars Discovered in a Survey of Mid-Latitude EGRET Error Boxes GBT04B-022 [B] PI Thomas Troland The magnetic field in a compact high velocity cloud GBT02A-044 [P] PI Richard Barvainis A Search for CO from the Epoch of Reionization GBT04C-012 [B] PI Jennifer Donovan Deep Searches for Young Pulsars in ``Shell'' Supernova Remnants GBT04B-036 [B] PI Paul Demorest Precision Timing of Binary and Millisecond Pulsa GBT04B-037 [B] PI Scott Ransom A Pilot 350MHz Survey for Fast Pulsars 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 ~ 347 [152] 332 [264] 425 [140] 404 [019 Maintenance ~ 210 91 [051] 21 [077] 28 [077 Test & Comm ~ 158 [044] 275 [048] 212 [026] 131 [006 Shutdown ~ 0 0 36 36 Un-assigned ~ 5 46 27 146 Proposal Checkouts ================== Awaiting checkout - 0 Active checkout - 19 On Hold - 5 Schedule - 66 Completed - 219 Current backlog [hours prior to 04B*] = 1137 Total time to discharge [hours] = 2864 * Includes projects that are on hold for trimester 04B -- RCB 4. Frontends, IFs, and Spectral Baselines Operational issues: No unusual problems this week. Baselines: System test time was not available, so I have begun drafting an addendum to EDIR 312 describing the progress over the past year. And, we have begun looking at using Multi-Chip Module (MCM) technology for future receiver construction. Q-band: Testing continues. It appears fairly certain that mixer image noise is a significant contributor to the receiver output noise power ripple. We are looking at various possibilities to address this effect. Ka Receiver: Testing of the receiver stability and software got underway this week and went well. Adjustment of gain and phase balance and noise temperature measurements will start soon. RF testing of the mmConverter modules is progressing independently, and is about 80% done. Other: R. Norrod 9/9/2004 5. Spectrometer Status Spectrometer Report 2 September - 9 September 2004 *****Operations***** There were a few complaints about 1024 lag long pulses in the autocorrelation function (acf). Also there were complaints about longer steps in the acf. This is simply a known problem revisited. Chen concluded in July that these steps were due to problems writing to disk. Subsequently, Ford requested a software update that should fix the problem. The interim work-around is to filter out bad integrations. There was some user-provided software to do this. *****Development***** LTA replacement: Work on LTA PCB design is continuing. 50% finished. Spigot Mode Testing: Karen ran a number of tests with the spigot this week to look for RFI found by Ransom at 5.55 & 11.1 MHz (possibly from the reference signals)and at 1.31 ms (possibly from the spectrometer). The tests were done by hooking up the artificial pulsar as a noise source straight to the spectrometer and taking data in 6 different modes using the maser and then with the rubidium standard. The data from these tests is still being analyzed, and hopefully an update will be available Friday morning. However, the preliminary results suggests that (1) the 1.31ms signal is consistently seen in the 4-bit spigot modes but not in any other mode (2) the 5.55MHz and 11.1 MHz RFI was not seen when just getting the signal from the noise source connected to the spectrometer. Further tests need to be run next week using the upstairs noise source and the full IF path. Additionally, further data reduction was done on the data taken last week to both explore the RFI issues in old modes and determine whether or not a number of new modes (including 2-bit modes) can be released for use. This matter was discussed with Ray during his time in Green Bank. He has some ideas about where this might come from and will look into further. Cross-Correlation Test Fixture: The filter board was received from the manufacturer last week. Incoming inspection revealed one problem: two critical line widths were off by a factor of two in one of the microstrip filters. Tests with a network analyzer showed filter shapes that were about as expected for the line widths actually manufactured. The shop attempted to trim the offending line to the correct width but was unsuccessful. The design of the combining and output module continued. Component selection is complete, and all required components are either here or on order. Spigot true-200 MHz modes: Tests were conducted Thursday and will continue through Friday. Two modes, 81 and 82 passed engineering check-out. Problems were found with mode 83. *****Plans***** - Continue LTA replacement and Cross-Correlation Text Fixture development. - Follow up on 1.31 ms "interference". - -- Rich, Karen and Holly 6. Software Status Single Dish Development IPT #97 - Friday, September 10, 2004 This is week 4 of 6 in the sixth development cycle (C6) in 2004. The Plan of Record is available from the wiki at Software.PlanOfRecordC62004. Work on the Data Handling project continued this week. Jim, Bob, and Paul spent most of their week working on IDL development for the GBT. Documentation is available on the wiki at Data.IDLMain. The IDL code generated to date has been placed under revision control and current work focuses on finding a memory leak exposed during the manipulation of large FITS files. Development of Ka Band software, Spectrometer/Spigot fixes, and the porting of the rest of the receiver managers to Linux continued this week. The Tcal measurements for the Ka Band receiver were added to the Measurements database this week by Galen. Observing API work also continued this week. We are busily working toward our beta release date of September 17. We plan on having a technical seminar on the Observing API sometime around the release date. Stay tuned for details. The changes to the Spectrometer data pipeline were sponsor tested this week. There are still a few system issues remaining, (i.e. NFS write performance), but the pipeline has taken care of the coupling issues between NFS and data acquisition. This task is on schedule for release at the end of the cycle. With regard to the Spectrometer Stop/Abort issues, a fix has been implemented and tested. However, there is still one additional abort case needs to be handled. In support of Spigot Ease of Use, the new gbtstatus daemon/text file generator and console screen client are operational. Simply type 'gbtstatus' at a Linux prompt to take a peek at the beta product. Work continues on creating Observing API scripts to support Spigot observations. Operational support this week included assistance in ongoing subreflector investigations. -- AS 7. Project Planning Status September 7, 2004 Planning Meeting Minutes Rm 137 10:00 A.M. [0] Observer comments & operator log items resulting in lost time: Observer's comments: Operator's log comments Significant failures the past week stemmed from: Computing: None Software: Dynamic corrections, Spectrometer manager, Transporter on Wind, DCR, Antenna Manager, Spectrometer bad lags, IF Rack filter changed spontaneously Electronics: OD 2 has lack of power, CM5 John mentioned that there needs to be notification of some sort that goes to the electronics division when a fault like these happen, so that they can be repaired. Without going through the operators log every morning, we have no way of knowing that a fault happened. John suggested that the operators email to gbelectronics when an electronics item breaks. John and Bob Anderson will discuss it. Telescope/Servo: Subreflector drive, AZ brake switch Subreflector drive problem is that the subreflector cannot follow the precise trajectory needed for doing focus scans at speed. Investigations are underway. There does not appear to be a mechanical or electrical problem. A logic analyser was hooked up to the as brake fault system to try and trap the faulty switch. Other Problems from Observing Reports: None. [1] Resource calendar schedule conflicts and discussions None. [2] Observing Schedule discussions PF2 scheduled for BU after rcvr off? Pete and Carl will coordinate the PF2 removal based on the weather and the observing. October 2nd and 3rd there will be a network interruption due to work in CV. More details will follow closer to the outage. [3] GBT development planning EoR interferometer work Support from the shop for building more nodes is not an undue burden. 300-800 MHz feed requested Carl reiterated that a dual-frequency feed for PF1 is important to relieve scheduling bottlenecks for pulsar monitoring programs. NRL amplifier work Electronics will provide technician time, but no engineering effort for building some amplifiers for NRL under contract. No engineering effort is available to help with EVLA receiver designs [4] AOB None -- JF 8. Any other Business