GBT Operations & Commissioning Meeting
AGENDA
The mechanics found the grout under joint 31 to be crushed. We are in the process of replacing it, along with about 2 feet of grout under baseplate 32 adjacent to joint 31. By the time of the meeting, the epoxy grout should be in its curing process.
We are also taking advantage of the time to make progress on the HVAC controls upgrade.
Approval packages for the track components are at AUI's office now. We hope that it is going to the NSF today (Friday).
We supported 15 projects in 23 observing sessions, including one VLBI run. Average setup time was 18 minutes, higher than usual because of the number of problems that I will outline shortly. The telescope was also scheduled (originally) for 9.5 hours for maintenance and 8 hours for program checkouts.
Lost time was unusually high -- 27.6 hrs or about 17% of the time scheduled for tests or observing. The track grout problem was the major cause. We cancelled about 8.5 hrs of observing to add an unscheduled maintenance day. The other causes of lost time were also unusually high. Here's a summary of this week's problems:
- Grout repairs : 8.8 hrs
- Low temperatures : 4.3 hrs
- Astrid (lockups, database problems, ...) : 3.5 hrs
- High winds : 2.8 hrs
- Elevation drive squeal : 2.1 hrs
- Human error (Using GHz instead of MHz) : 2.1 hrs
- Elevation brake fault : 1.9 hrs
- gbtaio2 loose cable : 1.0 hrs
- VNC segmentation faults during remote observations : 0.6 hrs
- All others : 0.6 hrs
We have been asked to help the SDD in determining why Astrid problems have increased substantially. We also have been discussing ways to reduce the chance of human errors when specifying hardware configurations.
Last Week
=========
Observations for proposals
GBT06A-062, GBT05B-042, GBT06A-066,
GBT06A-001, GBT04C-043, GBT05C-045,
GBT06A-049, GBT06A-027, GBT06A-028,
GM060 , GBT04A-038, GBT04A-006,
GBT01A-005, GBT05C-019, GBT06A-060
Completed proposals
GM060, GBT04A-006
Next Week
=========
Observations scheduled for **
GBT06A-051 [ B] Marcel Agueros
Detecting Pulsar Companions to Very Low-Mass
White Dwarfs
GBT06A-042 [ P ] Raghvendra Sahai
A Mysterious Outflow Source --- Protostar, Dying
Star, or Something Else ?
GBT06A-066 [F B] David Nidever
HI Mapping of the Extended Magellanic Stream
GBT06A-001 [ B] Vincent Fish
SiH: The Hiding Hydride
GBT05B-032 [ B] Steve Thorsett
Timing the millisecond pulsar B1620-26 with the
GBT
GBT05C-020 [ P ] Tony Remijan
Confirmation Of Interstellar Methyltriacetylene
(CH3C6H) Toward Tmc-1
GBT05C-065 [ P ] Jim Braatz
Measuring the Extragalactic Distance Scale: A
Target of Opportunity
GBT06A-046 [ B] Glen Langston
A search for the Largest Interstellar Molecule,
HC_13N
GBT05B-023 [F ] Adrienne Juett
A Search for Radio Pulsations from the Accreting
Millisecond X-ray Pulsar SAX J1808.4-3658
GBT05C-022 [ P ] Jim Braatz
The Accretion Disks and Supermassive Black Holes
in NGC 2273 and NGC 4051
GBT05B-034 [F B] Ingrid Stairs
Timing Binary and Millisecond Pulsars from the
Parkes Multibeam Survey
GBT06A-003 [ B] Chris Clemens
Observational Tests for Non-radial Oscillations
in Radio Pulsars
GM062 [F ] M. Orienti
What causes the very broad HI absorption in radio
galaxies?
GBT05C-045 [F ] Scott Ransom
A 350-MHz Survery of the Northern Galactic Plane
for Pulsars (continued)
GBT06A-027 [F ] Karen Masters
Mapping Matter in the Nearby Universe with 2MASS
GBT06A-049 [ P ] Tony Readhead
Definitive Detection of Excess Arcminute Scale
CMB Anisotropies
GBT06A-028 [F ] Jack Hewitt
Mapping Radio Recombination Line Emission Toward
SNRs W28 and W44
GBT05C-029 [ B] Trinh Thuan
The HI Content of Extremely Metal-deficient Blue
Compact Dwarf Galaxies
GBT06A-060 [F ] Andrew West
A Search for HI Associated with New Milky Way
Companions
** Scheduled as F-ixed, P-rimary, B-ackup
Contact Information for 03/09/2006 - 03/23/2006
=======================================
Proposal PI Bands Email [NRAO contact]
---------- ------------------ ----- --------------------
GBT06A-053 Scott Ransom S sransom@nrao.edu [Scott Ransom]
GBT06A-032 Jim Braatz Q jbraatz@nrao.edu [Jim Braatz]
GBT05A-020 Yancy Shirley K yshirley@as.arizona.edu [Frank Ghigo]
GBT06A-044 Jeremy Darling 3 jdarling@origins.colorado.edu [Frank Ghigo]
GBT06A-066 David Nidever L dnidever@virginia.edu [Jay Lockman]
GBT05A-033 Ingrid Stairs L istairs@astro.ubc.ca [Scott Ransom]
GBT04C-031 Paul Kondratko K pkondrat@cfa.harvard.edu [Jim Braatz]
GBT06A-068 Yancy Shirley K yshirley@as.arizona.edu [Toney Minter]
GBT05B-044 Maura McLaughlin 3 mclaughl@jb.man.ac.uk [Scott Ransom]
GBT04C-043 Scott Ransom 3 sransom@nrao.edu [Scott Ransom]
GBT06A-014 Andrea Tarchi K atarchi@ira.cnr.it [Jim Braatz]
BB217 Edward Boyce C eboyce@nrao.edu []
GBT05C-023 Fernando Camilo 3 fernando@astro.columbia.edu [Scott Ransom]
GBT05C-046 Ingrid Stairs L istairs@astro.ubc.ca [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]
GBT06A-038 Tom Troland L troland@pa.uky.edu [Jay Lockman]
GBT04A-038 Brian Mason B bmason@nrao.edu [Brian Mason]
GBT06A-018 Joe McMullin Q jmcmulli@nrao.edu [Dana Balser]
GBT06A-009 Jim Condon K jcondon@nrao.edu [Jim Braatz]
GBT06A-050 Steve Begin S sbegin@physics.ubc.ca [Scott Ransom]
Scheduled hours [backup]
========================
Category/Month-> February March April May
Astronomy ~ 490 [038] 615 [405] 542 [492] 477 [326]
Maintenance ~ 55 [009] 23 [077] 16 [102] 20 [068]
Test & Comm ~ 122 [007] 106 [042] 147 [046] 144 [039]
Un-assigned ~ 6 0 17 103
Proposal Checkouts
==================
Awaiting checkout - 0
Active checkout - 0
On Hold - 22
Schedule - 70
Completed - 455
Current backlog [hours prior to 06A*] = 1035
[2001:2(1), 2002:60(1), 2003:19(1), 2004:161(11), 2005:665(34), 2006:128(3)]
Total time to discharge [hours] = 3037
* Includes projects that are on hold for trimester 06A
Operations
PF1:
Telemetry on 340 MHz, Y1 amplifier showed that it might have been
defective. Determined by test that it was functional. At operations
request, we then replaced the 800 MHz feed with the 340 MHz feed and vetted the system.
IF System:
Removed last ODM with a Milliwave amplifier. Corrected instability problem
in LInk #6 found while searching for a problem with a K band observing run.
1-8GHz IF Amplifiers:
Construction completed on four new IF amplifiers with one tested and being
installed into an ODM. Troubles with regulators have delayed completion.
National regulators were ordered which do not have heat related failures.
VLBI:
Working to track down the cause of a glitch in the VLBI DAR 1PPS signal which happened a few times before/during last week's run.
Development
Ka RX, Zpectrometer:
Components for redesigned phase switch driver on order. Couplers are
plated, being sent from CV.
Lab Spectrometer IF System:
Some long lead time components on order, filter designs being modeled in
MWO, physical layout being modeled in Inventor.
Converter Module Power Sampler Upgrade:
Components on order, chassis design to fit existing video amp footprint
in progress.
ORM Power Divider:
Construction completed on prototype unit and bias circuit tested. Two of
the five MMIC amplifiers failed, and a batch of voltage regulators seem to be defective. These are being bypassed until more components arrive.
C-Band Receiver Redesign:
Trade-off studies (noise, level analyses), parts selection and layout
modeling ongoing. Draft of interface specification was written and
distributed to project team members.
3mm Rx:
GB machine shop is nearly finished with stainless-steel wavguide dewar
feedthroughs. Submitted work order last week for a vacuum port adaptor.
MLLN 140 Project:
Devised a scheme for extending the bandwidth to 3 GHz and providing more
outputs from the fiber optic link using Mini-Circuits surface mount
parts. Designed boards and boxes. Completed layout and analysis of PLL
for filtering a 128 MHz band from the 3 Ghz bandwidth using the VLBI LO's
as references.
23Feb06 - Norrod, Anderson, Simon, Stennes, Watts, White
Digital Electronics Status 16 Feb. 2006 – 23 Feb, 2006
***Operations, Problem summary***
The active surface has had a problem for about a week: one of the modules forgot its address. In an attempt to fix that on Thursday, we managed to scramble several other addresses. This left about one-eighth of the surface in questionable shape. But we leaned a lot. Also, we received some advice from the active surface electronics manufacturer. Fortunately, we have maintenance on Friday and hope to get everything working again.
***Development***
Cal-Tech Continuum Backend (CCB):
A good part of the group was out for the whole week so little was accomplished. One of the power supplies was partially tested.
Test Spectrometer
Very little progress.
***Plans***
- Continue CCB construction.
- Continue LTA troubleshooting
This ends Week 1 of 6 in the second development cycle of 2006 which can be viewed at PlanOfRecordC22006.
The MR for fixing stop and abort for pulsar observations has been signed by its sponsor, ScottRansom, and is ready for CCC review.
Two antenna MRs have been signed by their sponsor, DanaBalser, and are ready for CCC review. The first MR is an enhancement to the antenna FITS file which will allow the LFCs to be recorded in the FITS file primary header. The second MR deals with a bug fix for the Antenna FITS file columns, OBSC_AZ & OBSC_EL.
Penn Array development hit a snag this week. We upgraded to the latest IRC release. Because of IRC architecture changes, we had to modify the GBT FITS archiver to work with the new version of IRC. This work has been slow because there are no release notes available for IRC. We are currently testing the new version of IRC with the archiver changes. The new version of IRC appears to have issues with resource management (memory leaks) and to be less reliable than the previous version.
Operational support for this week included:
- Investigated and patched in a fix for an Astrid memory leak.
- Restarted the mySQL service on leo.
- Assisted an observor in refilling data that was not filled in /home/sdfits because sdfits had stopped.
- Patched in a fix to gbtstatus to address the cause of the lock-ups seen over the weekend.
Timekeeping metrics are now being kept for SDD work. Early returns can be seen at MetricsC12006.
Wasted way too much time this week trying to get software that would allow me to plan and pseudo-optimize the 350MHz pulsar survey as done in drift-scan mode. I wasn't planning on needing to do that anytime soon, but we're getting lots of usable data at least. The process seemed to be successful and will probably be useful again next summer. A side benefit of all of this was that I managed to get a set of python wrappers for SLALIB working that I found on the web (I sent the wrappers and instructions for compiling to Mark Clark today).
In other news, Mark finished the first cut at getting the spigot abort code working in Astrid. I'm supposed to test this tomorrow (i.e. Friday) morning just before this meeting. If there are issues, I'll probably be late to the meeting...
MIT/LL 43m Project -- Glen
The computer installation work by MIT/LL has been completed. Testing has started.
We had some trouble with one of the RF cables going to the LL trailer, but this
has been repaired.
Tim and John have made good progress on the installtion of the PLC. We plan first
astronomical source tracking for a few hours this afternoon, Friday Feb 24.
Project engineer Mike Shields will be in Green Bank starting on Monday Feb 27, for
one week. He will be looking at upgrades to receiver system to reduce the system
temperature.
Extensive antenna motion limit testing will be performed next week.
-- RichardPrestage - 23 Feb 2006
Revision r1.11 - 24 Feb 2006 - 14:48 GMT - NicoleRadziwill
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