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GBT Operations & Commissioning Meeting

28th April 2006

AGENDA

Az Track, Antennae Report -- Bob

Observing News -- Ron

The news this week is the lost time Monday night, much of which was exasperated by the phone outage. The CCB lost its power supply but, without phones, folks had to drive to homes to get assistance. In the attempt to fix the CCB, the upper elevator became stuck at the top of the feed arm and observing couldn't start. More driving to get more help. The network and a few other systems also had problems that may have been phone related and which required a bit of rebooting. To replace the power supply, 1 hour of observing was cancelled on Thursday morning. In total, 7.5 hrs was lost due to these problems.

The other problems during the week were much more typical.:

The network slowness occurred Sunday afternoon, and Wednesday morning and night. This is the first extended setup we've seen in many months but the logs didn't explain why. The RFI was from Ku-band satellites -- both the observer and I didn't realize he was going to be hit so hard. In all 12.7 hrs, about 9% of the time schedule for observing, was lost.

In general news, we supported 12 projects in 26 observing sessions, including one VLBI run. Average setup time was 13 minutes. The telescope was scheduled for 18 hrs of maintenance (which includes the added time for CCB repairs), and 3.5 hours of receiver checkout.

Scheduling Status -- Carl 

Last Week
=========

Observations for proposals
   GBT06A-044, GBT06A-056, GBT06A-046, 
   GBT06A-014, GBT06A-047, GBT06A-003, 
   GBT06A-026, GBT06A-049, GBT06A-027, 
   GBT06A-039, BB223     , GBT05C-019

Completed proposals
   GBT06A-044, GBT06A-003, BB223

Next Week
=========
Observations scheduled for **
  GBT06A-063 [ PB] Martin Zwaan
       Where are the molecular absorption lines?         
  GBT06A-030 [F  ] Don Campbell
       Lunar surface studies via S-Band radar imagery    
       and interferometry                                
  GBT06A-054 [  B] Paul Demorest
       Long-term Precision Timing of Millisecond Pulsars 
  GBT06A-032 [ P ] Jim Braatz
       A Search for the First SiO Megamaser              
  GBT06A-065 [ P ] Rachel Friesen
       Probing the initial conditions of star formation  
       in Ophiuchus                                      
  GBT05B-042 [F  ] Michael Kramer
       Timing and General Relativity in the Double       
       Pulsar System                                     
  GBT06A-022 [ P ] Jim Braatz
       Water Vapor Megamasers in an X-Ray Selected       
       Sample of AGNs                                    
  GBT05B-032 [  B] Steve Thorsett
       Timing the millisecond pulsar B1620-26 with the   
       GBT                                               
  GBT06A-056 [ P ] Paul Kondratko
       Are there Unrecognized NGC4258-like Systems Among 
       Known Water Masers in AGN?                        
  GBT05C-065 [ P ] Jim Braatz
       Measuring the Extragalactic Distance Scale: A     
       Target of Opportunity                             
  BK127      [F  ] Kirsten Knudsen
       Resolving the AGN and the starburst in an         
       intensely starforming quasar                      
  GBT06A-046 [ PB] Glen Langston
       A search for the Largest Interstellar Molecule,   
       HC_13N                                            
  GBT05B-034 [  B] Ingrid Stairs
       Timing Binary and Millisecond Pulsars from the    
       Parkes Multibeam Survey                           
  GBT06A-047 [ P ] Miguel Angel Requena-Torres
       Complex Molecules in the Galactic Center          
       molecular clouds                                  
  BK114      [F  ] Paul Kondratko
       Follow­up Imaging of Three NGC4258­like Water     
       Megamasers Discovered with the GBT                
  GBT06A-026 [  B] Nissim Kanekar
       A search for 21cm absorption towards MgII         
       absorbers in the redshift desert                  
  GBT06A-049 [ P ] Tony Readhead
       Definitive Detection of Excess Arcminute Scale    
       CMB Anisotropies                                  
  GBT06A-038 [  B] Tom Troland
       Magnetic Fields in the Galactic Halo via the HI   
       Zeeman Effect                                     
  GBT06A-027 [  B] Karen Masters
       Mapping Matter in the Nearby Universe with 2MASS  
  GBT06A-018 [ P ] Joe McMullin
       Isotopic Abundances in Planetary Nebulae          
  BM241      [F  ] Anupreeta More
       A High Frequency Hsa Study Of The Gravitational   
       Lens 2016+112                                     
  GBT06A-070 [ P ] Fernando Camilo
       Studying (transient) pulsed radio emission from a 
       magnetar                                          
  GBT06A-061 [  B] Martin Zwaan
       HI 21-cm absorption in MgII and CaII absorbers    
** Scheduled as F-ixed, P-rimary, B-ackup

Contact Information for 05/11/2006 - 05/25/2006
=======================================
Proposal   PI                 Bands Email [NRAO contact]    
---------- ------------------ ----- --------------------
GBT06A-063 Martin Zwaan       L     mzwaan@eso.org [Karen O'Neil]
BF089      Jan Forbrich       X     jforbrich@mpifr-bonn.mpg.de []
GBT06A-020 Laurent Wiesenfeld X     Laurent.Wiesenfeld@ujf-grenoble.fr [Ron Maddalena]
GBT06A-032 Jim Braatz         Q     jbraatz@nrao.edu [Jim Braatz]
GBT04C-050 Wendy Lane         A     wendy.peters@nrl.navy.mil [Rick Fisher]
GBT06A-065 Rachel Friesen     K     rfriesen@uvastro.phys.uvic.ca [Toney Minter]
GBT06A-022 Jim Braatz         K     jbraatz@nrao.edu [Jim Braatz]
GBT06A-011 Mike Blanton       L     blanton@nyu.edu [Karen O'Neil]
GBT06A-067 Amy Lovell         L     alovell@agnesscott.edu [Toney Minter]
GBT06A-056 Paul Kondratko     K     pkondrat@cfa.harvard.edu [Jim Braatz]
GBT05C-042 Scott Ransom       S     sransom@nrao.edu [Scott Ransom]
GBT05C-043 Nissim Kanekar     Q     nkanekar@nrao.edu [Dana Balser]
GBT04C-031 Paul Kondratko     K     pkondrat@cfa.harvard.edu [Jim Braatz]
GBT05C-065 Jim Braatz         K     jbraatz@nrao.edu [Jim Braatz]
GBT06A-046 Glen Langston      U     glangsto@nrao.edu [Glen Langston]
GBT05B-034 Ingrid Stairs      L     istairs@astro.ubc.ca [Scott Ransom]
GBT06A-047 Miguel Angel Reque U     requena@damir.iem.csic.es [Ron Maddalena]
GBT06A-026 Nissim Kanekar     8     nkanekar@nrao.edu [Toney Minter]
GBT06A-038 Tom Troland        L     troland@pa.uky.edu [Jay Lockman]
GBT06A-049 Tony Readhead      B     acr@astro.caltech.edu [Brian Mason]
GBT06A-027 Karen Masters      L     kmasters@cfa.harvard.edu [Karen O'Neil]
GBT05C-046 Ingrid Stairs      L     istairs@astro.ubc.ca [Scott Ransom]
GBT06A-039 Fernando Camilo    S     fernando@astro.columbia.edu [Scott Ransom]
GBT06A-018 Joe McMullin       Q     jmcmulli@nrao.edu [Dana Balser]
GBT05C-037 Nissim Kanekar     A     nkanekar@nrao.edu [Glen Langston]
GBT06A-009 Jim Condon         K     jcondon@nrao.edu [Jim Braatz]
GBT06A-070 Fernando Camilo    CUSX8 fernando@astro.columbia.edu []
GBT05C-019 Tim Robishaw       L     robishaw@astro.berkeley.edu [Toney Minter]
GBT06A-050 Steve Begin        S     sbegin@physics.ubc.ca [Scott Ransom]
GBT06A-061 Martin Zwaan       A     mzwaan@eso.org [Karen O'Neil]

Scheduled hours [backup]
========================
Category/Month-> April     May       June      
    Astronomy ~  590 [030] 533 [335] 135 [027] 
  Maintenance ~   59        20 [068] 177       
  Test & Comm ~   71 [004] 156 [041]  22 [003] 
  Un-assigned ~    0        35       388       

Proposal Checkouts
==================
Awaiting checkout - 0
  Active checkout - 4
          On Hold - 21
         Schedule - 85
        Completed - 480


Current backlog [hours prior to 06A*] = 963
   [2001:2(1), 2002:88(2), 2003:19(1), 2004:131(8), 2005:595(27), 2006:128(3)]
   Backlog excluding 111 hrs of monitoring projects after 06A = 853
Total time to discharge [hours] = 3475
   Includes 314 hours of monitoring after trimester 06A
* Includes projects that are on hold for trimester 06A

Microwave Electronics Status -- Roger

Operations:

Development:

MLLN Project:

the two way divider is finished. After looking at the 140 amplifiers, decided to modify the two way divider with additional amplification.

Antenna Range:

turret rotation. We are currently at the limit of rotation speed versus accuracy. Fixed some other problems and added features put forth in a wish list.

Power Divider:

C-Band Receiver Upgrade:

3mm Receiver:

Digital Electronics Status -- Rich

Digital Group Status 20-APR-06 THRU 26-APR-06

***Operations, Problem summary***

This week, the CCB had a problem that cost considerable down time. Basically, following a brief power outage during the wee morning hours of Tuesday the 25th, the CCB failed to respond. Attempts were made to remotely re-boot the unit by way of its companion M&C Reset Box to no avail (neither a remote reset nor a remote power-cycle would correct the problem). John Ford and Brian Mason trekked up to the receiver room and tried both a manual (front panel) reset and power-cycle; again, with no success. We retrieved the unit Tuesday morning and returned it to the lab. Further testing indicated that the Lippert CPU board would "lock up" whenever its +5V power supply dropped below about 4.85V (a known issue from previous testing). Otherwise, everything seemed to be in perfect working order. At that point we developed a theory that, over time, the external +5V power supply may have drifted down a bit; setting us up for problems which occurred when the mains power glitched. On the morning of Thursday the 27th, we re-installed the CCB on the GBT, adjusted the external +5V power supply's output to a more suitable voltage (it was about 0.4V lower than optimal), then powered up the unit. At that point, the CCB began functioning normally, responded correctly to Martin's Demo_Client, and reported all system voltages to be within nominal operating envelopes. As far as we can tell, the unit is now alive and well, and will be used for observing all day today (Thursday).

The Active Surface required a bit of attention during maintenance time to clear a patch of 64 bad antennas.

***Development***

Cal-Tech Continuum Backend (CCB):

This week we suspended any testing of modules for the 2nd CCB in response to a problem with the first article CCB installed on the GBT. It is now anticipated that the second CCB will be complete the second week of May.

Lab Spectrometer

Software for the 800 MHz mode has been revised to account for the measured way in which lags are delivered by the hardware. This was successfully tested this week. The spectrometer is now producing reasonable 800 MHz spectra on all four inputs. The only obvious fly in the ointment are birdies at multiples of 100 MHz. We have found that these are due to the samplers and are working on fixing them.

The defective sampler mentioned last week was fixed. The cause of failure was a bad comparator chip, as we had suspected. During the course of fixing this sampler, we noticed that a second sampler had similar problems. These have not been fixed yet.

LTA Upgrade

Randy has continued to familiarize himself with the spectrometer in general and the LTAs in particular. His goal is to produce a design for an improved LTA.

Miscellaneous

ALMA Jason, JD and Rich continue to spend time on this project.

***Plans***

- Continue CCB construction... - Continue Lab Spectrometer commissioning - Continue ALMA support as needed...

Randy and Rich

Software Status -- Mark

This ends Week 4 of 6 in the third development cycle of 2006 which can be viewed at PlanOfRecordC32006.

Operational support for this week included:

We are planning on releasing GBTIDL v2.0 on May 5, 2006. Release notes will be emailed to gbtlocal prior to the release.

Summary of Cycle 3 MRs:

Pulsar Related -- Scott

Very little accomplished this week except for work on a very cool ToO? for GBT and on data from a similar proposal at Parkes (and talk hosting and committee meetings -- blech).

MIT/LL 43m Project -- Glen

Normal spacecraft tracking continues to be successful. Parts of April 26th's tracking pass was carried out remotely, with the GBT operator occasionally monitoring the 43m status.

Work continues on the 2007 and 2008 statement of work. Progress was made on the press release, but the original version needs to be revised and re-submitted to MIT/LL.

We are preparing to set-up a work area at the 43m for installation and testing of the MIT/LL dewar in June 2006.

Any other Business

-- RichardPrestage - 27 Apr 2006

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