Digital Electronics Status 19 Jan 2006 – 26 Jan 2006

***Operations, Problem summary***

No significant problems this week.

***Development***

Cal-Tech Continuum Backend (CCB):

Work continues on the CCB backends. Daughter cards are being tested. The test procedure for the daughter cards is being refined during this testing exercise. Construction of the second and third Master Cards is nearly complete. Documentation is also being upgraded.

Long Term Accumulator

Work continues at about a 20%FTE level. Detailed timing is being studied on one of the spare LTAs to try to understand why it gets occasional errors.

***Plans***

- Continue CCB construction. - Continue LTA troubleshooting.

Operations:

• The refrigerator on L-Band jammed on Sunday night. The receiver was warmed up, the refrigerator was replaced, and the receiver recooled.
• PF1 was reinstalled on the GBT on January 30. PF2 was removed from the GBT.

Projects:

• Ka Receiver
  • The next generation phase switch driver prototype has been constructed, modified and a design finalized. Switching times of less than 100 nSec and settling times of about 600 nSec are being seen, well within the 1 uSec CCB spec. A switching circuit adapted for constant current draw from a UMd/Andy Harris circuit is being used.
• Zpectrometer
  • Components for signal couplers were completed by the shop, two couplers have been assembled and await further machining before testing can be performed, if tests are successful four more couplers will be assembled, machined, and all six couplers will be sent to CV for plating.
• Converter Module Power Samplers
  • CMs 4, 8, 11 and 15 were checked in the system and it appears the design will need about 20 dB of gain for power readings to be in a usable part of the samplers' range at power levels typically seen by observers desiring the expanded range samplers. The prototypes installed do have readings that change with power levels, but on a scale of small fractions of a volt instead of volts. Gain can be accomplished through simple, inexpensive MMIC amplifiers.
• Q band improvements
  • Work continues on the test dewar design

• Any computing items
  • RHEL 4 problems with RPC/NFS
    • Chris believes that these are solved. Testing is ongoing
  • Spigot RAID maintenance issues
    • We should try to move to RHEL on this machine. Chris says that the file systems needed are available, but not standard.
• Review of minutes from last meeting
• Review MR's for this cycle
  • None
• Review new list of CurrentObservingReports? requests (not including Astrid requests) and operator log items
  • Numerous Astrid problems
    • scan coordinator comms
      • Possibly caused by message mux problem and PF1 manager turned on while PF1 is not on the telescope
    • coord mode to antenna
      • Unknown problem
    • other usual lockups
      • Some work was done on this last week, and it should be improved
  • Turret problems
    • These are thought to be mechanical in nature, and work was done this week to improve them.
  • Weather shutdowns
  • L band failure
    • Another fault on L band. I have asked Cryo to propose a solution to these infant failures.
  • AZ motor faults
    • intermittent fault, goes away if you just pick up and go on.
  • Low K band power levels at IF rack
    • This is due to using a very narrow band IF filter on a wide bandwidth receiver. Ron will coordinate a study by the science staff on what to do about the problem.
• Other business
  • Discussed future of CCC meetings. Talked about splitting off the fault discussions for the Friday meetings, and leaving the planning and approval parts for occasional meetings. We'll not change anything right now.

Had a talk this week with Chris about upgrading spigot/spigot2 to a new kernel with XFS filesystem and Linux Kernel 2.6 safe EDT drivers. He thinks it is a good idea in general. So now we just have to find time to do it and then take a large amount of data to make sure it is stable and doesn't cause TICK errors.

Not much else "exciting" happened this week given proposal deadlines.

Note: I'll likely miss the meeting tomorrow morning as I will be at the UVa Grad Student seminar which is taking place all day and/or running my Ter5 observations....

We had a pretty good, productive week. We supported 18 projects in 26 observing sessions, including 2 radar and 1 VLBA run. We had extra maintenance this week (24 hrs) plus 4.5 hrs of program checkouts, 2 hrs for receiver checkouts, and 5 hrs for software tests.

Average setup time was 16 minutes. Over the last few weeks, I have been looking for patterns in what projects need the most setup time. Except for user experience, so far I'm not seeing any patterns. The range in setup times seems so far to be happenstance.

Lost time was good -- about 6 hrs or 4% of the time scheduled for everything but software tests. More than half of this was due to the weather. The major causes of lost time are:

• Low temperatures : 2.4 hrs
• User error in an Astrid script : 1.1 hrs
• L-Band cryogenics : 0.7 hrs
• Spectrometer : 0.7 hrs
• PF1 manager left on : 0.6 hrs
• All others : 0.5 hrs

Lost time from Astrid was 0.2 hrs -- typically it's been consistently about 2 hrs per week. Maybe this is a statistical fluke. But I think not since this was a slightly heavy week with wide ranging projects.

Last Week
=========

Observations for proposals
   GBT06A-062, GBT05A-041, GBT04C-050, 
   GBT06A-044, GBT06A-056, GBT04C-031, 
   GBT05C-010, GBT05B-034, GBT05C-056, 
   GBT05C-057, GBT04B-014, GBT05C-015, 
   GBT04A-038, GBT06A-009, BB191     , 
   GBT05C-019

Completed proposals
   GBT05C-056, GBT05C-057, GBT05C-015, 
   BB191, GBT05C-012

Next Week
=========
Observations scheduled for **
  GBT06A-062 [F  ] Jean-Luc Margot
       Venus spin dynamics                               
  GBT05A-041 [F B] Paul Demorest
       Precision Timing of Binary and Millisecond Pulsars
  GBT06A-066 [F B] David Nidever
       HI Mapping of the Extended Magellanic Stream      
  GBT05C-042 [F  ] Scott Ransom
       Timing the Binary and Millisecond Pulsars in      
       NGC6440 and NGC6441                               
  GBT05A-011 [F  ] Scott Ransom
       Timing of the Binary and Millisecond Pulsars in   
       Terzan5                                           
  GBT06A-001 [F B] Vincent Fish
       SiH: The Hiding Hydride                           
  GBT05C-065 [ P ] Jim Braatz
       Measuring the Extragalactic Distance Scale: A     
       Target of Opportunity                             
  GBT04C-031 [ P ] Paul Kondratko
       Monitoring of Five NGC4258-like Water Megamasers  
       Discovered with the GBT and the DSN               
  GBT05C-010 [F B] Yi-nan Chin
       A Search for Interstellar Benzonitrile (C6H5CN)   
       -- A Key Tracer of Benzene                        
  GBT06A-014 [ P ] Andrea Tarchi
       H2O vs Continuum in the Megamaser 3C403:          
       Reverberation Mapping of the Nucleus              
  GBT06A-027 [  B] Karen Masters
       Mapping Matter in the Nearby Universe with 2MASS  
  GBT04A-038 [ P ] Brian Mason
       GBT Observations of Radio Sources in CBI          
       Intrinsic Anisotropy Fields                       
  GBT04A-027 [ P ] Brian Mason
       Determining the High Frequency Properties of mJy  
       radio sources                                     
  GBT06A-009 [ P ] Jim Condon
       H_0 and Dark Energy                               
  GBT05C-018 [  B] Tim Robishaw
       OH Megamasers in ULIRGs: The Mega-Obvious Place   
       to Look for Zeeman Splitting!                     
  GBT01A-005 [ P ] Barry Turner
       A High-resolution Spectral Survey Of Tmc-1 At     
       Q-band                                            
  GBT05C-019 [  B] Tim Robishaw
       The Galactic Arachnid in the Ursa Major Loop      
** Scheduled as F-ixed, P-rimary, B-ackup

Contact Information for 02/16/2006 - 03/02/2006
=======================================
Proposal   PI                 Bands Email [NRAO contact]    
---------- ------------------ ----- --------------------
GBT06A-051 Marcel Agueros     8     agueros@astro.washington.edu [Scott Ransom]
GBT06A-062 Jean-Luc Margot    X     jlm@astro.cornell.edu [Frank Ghigo]
GBT06A-042 Raghvendra Sahai   K     raghvendra.sahai@jpl.nasa.gov [Ron Maddalena]
GBT06A-043 Larry Morgan       L     lmorgan@nrao.edu [Larry Morgan]
GBT05B-042 Michael Kramer     L8    mkramer@jb.man.ac.uk [Scott Ransom]
GBT06A-066 David Nidever      L     dnidever@virginia.edu [Jay Lockman]
GBT05B-032 Steve Thorsett     L     thorsett@ucolick.org [Scott Ransom]
GBT05C-020 Tony Remijan       K     aremijan@pop900.gsfc.nasa.gov [Phil Jewell]
GBT06A-001 Vincent Fish       C     vfish@nrao.edu [Toney Minter]
GBT05C-065 Jim Braatz         K     jbraatz@nrao.edu [Jim Braatz]
GBT06A-046 Glen Langston      U     glangsto@nrao.edu [Glen Langston]
GBT06A-013 Jim Braatz         U     jbraatz@nrao.edu [Jim Braatz]
GBT05B-023 Adrienne Juett     SC    ajuett@virginia.edu [Scott Ransom]
GBT05C-022 Jim Braatz         K     jbraatz@nrao.edu [Jim Braatz]
GBT05B-034 Ingrid Stairs      L     istairs@astro.ubc.ca [Scott Ransom]
GBT06A-003 Chris Clemens      L     clemens@physics.unc.edu [Scott Ransom]
GM062      M. Orienti         L     orienti@ira.inaf.it []
GBT06A-004 William Reach      K     reach@ipac.caltech.edu [Toney Minter]
GBT05C-023 Fernando Camilo    8     fernando@astro.columbia.edu [Scott Ransom]
GBT06A-027 Karen Masters      L     kmasters@cfa.harvard.edu [Karen O'Neil]
GBT06A-049 Tony Readhead      B     acr@astro.caltech.edu [Brian Mason]
GM060      J. McKean          C     mckean@physics.ucdavis.edu []
GBT06A-028 Jack Hewitt        C     j-hewitt@northwestern.edu [Ron Maddalena]
GBT05C-026 Tom Devlin         XQ    devlin@physics.rutgers.edu [Brian Mason]
GBT04A-038 Brian Mason        B     bmason@nrao.edu [Brian Mason]
GBT04A-006 Joel Bregman       Q     jbregman@umich.edu [Frank Ghigo]
GBT06A-009 Jim Condon         K     jcondon@nrao.edu [Jim Braatz]
GBT05C-029 Trinh Thuan        L     txt@bluecompact.astro.Virginia.EDU [Karen O'Neil]
GBT01A-005 Barry Turner       Q     bturner@nrao.edu [Frank Ghigo]
GBT05C-019 Tim Robishaw       L     robishaw@astro.berkeley.edu [Toney Minter]
GBT06A-060 Andrew West        L     awest@astro.berkeley.edu [Karen O'Neil]

Scheduled hours [backup]
========================
Category/Month-> February  March     April     May       
    Astronomy ~  540 [322] 604 [398] 542 [492] 477 [326] 
  Maintenance ~   25 [043]  23 [077]  16 [102]  20 [068] 
  Test & Comm ~  107 [039] 103 [041] 147 [046] 144 [039] 
  Un-assigned ~    1        15        17       103       

Proposal Checkouts
==================
Awaiting checkout - 0
  Active checkout - 1
          On Hold - 23
         Schedule - 73
        Completed - 448


Current backlog [hours prior to 06A*] = 1102
   [2001:11(1), 2002:60(1), 2003:19(1), 2004:203(12), 2005:681(35), 2006:128(3)]
Total time to discharge [hours] = 3360
* Includes projects that are on hold for trimester 06A

Software Status -- Nicole

Software Status -- Amy

Today ends Week 5 of 6 in the first development cycle of 2006 which can be viewed at PlanOfRecordC12006. Our expected release date is February 15. However, that date may be pushed back a week or two depending on the results of integration/regression testing in order to ensure that we release a stable system.

Pre-integration testing of our upcoming release went well this week. The primary focus of the testing was to ensure a smooth transition to RHE4 and to ensure no behavioral changes had been introduced while moving to a new C++ compiler and updated Python version/Python modules. Integration testing begins next week.

We have more good news - the 15 second delay issue with RHE4 has been resolved via a joint venture with the Computing Division. The fix was to switch the NFS transport mechanism from TCP to UDP.

Due to heavy operational support and release preparation, the following MRs will not be completed this cycle:

• Quality Checks on Ka Band Receiver FITS Files
• Add Support for CCB to GFM

The sponsors for the MRs above have been notified and we will recommend rescheduling them for next cycle at the next cycle planning meeting.

Operational support items for this week included:

• Assisted Tim Robishaw in optimizing his GBTIDL scripts
• Assisted Tim Robishaw in tracking down bad data issues
• Responded to reports of repeated connection losses between the Scan Coordinator and the IF rack
• gbt2class user support

• • As Richard announced Wednesday, we have been told to proceed with getting NSF approvals for awarding contracts for the track work!! Carol is putting together the approval packages; the one for the baseplates should go out Friday (today). Wear plate and studs and nut packages should go out early next week. The field work contract needs some negotiation to get a final cost, but it should be lower than it is now. This is contingent on seeing all of our allocations come through, which we should know in a matter of days.

• • We serviced the turret positioner for the first time in its life this week. We found a number of loose bolts fastening the gear reducer in place, but not anywhere near falling out. We added oil to the reducer to make up for leakage. After tightening, the gear box still moves, since it is not dowelled nor does it have a torque block to prevent movement. However, this is unlikely to be the source of the misalignment for inserting the pin. The more likely cause was dirt on the rim of the turret table. Additional work will be considered this summer.

%META:TOPICINFO{author="RichardPrestage" date="1138906568" format="1.0" version="1.1"}% %META:TOPICPARENT{name="CommissioningMeetings"}%

GBT Operations & Commissioning Meeting

03 February 2006

AGENDA

• Az Track, Antennae Report -- Bob
• Observing News -- Ron
• Scheduling Status -- Carl
• Microwave Electronics Status -- John
• Digital Electronics Status -- Rich
• Software Status -- Nicole
• Change Control Committee -- John
• Pulsar Related -- Scott
• MIT/LL 43m Project -- Glen
• Any other Business

Az Track, Antennae Report -- Bob

Observing News -- Ron

Scheduling Status -- Carl

Microwave Electronics Status -- John

Digital Electronics Status -- Rich

Software Status -- Nicole

Change Control Committee -- John

Pulsar Related -- Scott

MIT/LL 43m Project -- Glen

Any other Business

-- RichardPrestage - 02 Feb 2006