GBT Operations & Commissioning Meeting
AGENDA
Activities List
-
- Our track work got off to a good start this week. As of this writing (Thursday morning), the wear plates, base plates, and splice plates have been removed from the first octant, and removal is well underway in the second. The contractors are on the steep part of the learning curve, but are fast learners. There's no one standing around waiting for instructions - everyone has their hands in the work. Our own crews have tasks to do as well, and their work has gone very well. By the end of this first week, we should see some pieces being placed for alignment, and demolition complete on the first two octants.
- We also removed two receivers and the feed defroster (hope we don't need that for a while!!!) this week, made a PF1 feed change, hoisted painting baskets into position, and performed a lot of other activities.
- Next week, we plan to remove two more receivers and install the RFI gimbal mounting.
We supported 15 projects in 20 observing sessions, including a VLB run. About 36.5 hrs of the track shutdown has gone to astronomy. Scott should be able to report on what fraction of this time has been useful. For the record, lost time before the track shutdown came from:
- Weather (0.9 hrs, 0.6%)
- Winds (2 instances) : 0.7 hrs
- Rain (K-band VLB) : 0.2 hrs
- Hardware/Software/Operations (3.3 hrs, 2.7%)
- Az Tachs/Torques "mystery" : 2.5 hrs
- Operator error - wrong receiver -- 0.6 hrs
- Others (SP, Astrid) : 0.1
- Observer Error (0.5 hrs, 0.4%)
- Solar Baselines : 0.5 hrs
Last Week
=========
Observations for proposals
GBT07A-053, GBT07A-098, GBT06A-054,
GBT06C-056, GBT07A-023, GBT05B-011,
GBT03C-030, GBT07A-058, GBT07A-037,
GBT07A-016, GBT06C-003, GBT06B-015,
GBT06C-105, GBT07A-080, BB231
Completed proposals
GBT07A-098, GBT06A-054, GBT07A-100,
GBT07A-023, GBT07A-080, BB231
GBT07A-058, GBT07A-037, GBT07A-016,
GBT06C-003, GBT06B-015, GBT06C-105,
Next Week
=========
Observations scheduled for **
GBT07A-053 [F ] Dunc Lorimer
A 350-MHz drift-scan survey for pulsars with the
GBT
** Scheduled as F-ixed, P-rimary, B-ackup
Contact Information for 05/17/2007 - 05/31/2007
=======================================
Proposal PI Bands Email [NRAO contact]
---------- ------------------ ----- --------------------
GBT07A-053 Dunc Lorimer 3 Duncan.Lorimer@mail.wvu.edu [Scott Ransom]
Scheduled hours [backup]
========================
Category/Month-> May June July
Astronomy ~ 531 362 500
Maintenance ~ 213 347 203
Test & Comm ~ 0 12 42
Un-assigned ~ 0 0 0
Proposal Checkouts #[hrs]*
=========================
Awaiting checkout - 25[838]
Active checkout - 0[0]
On Hold - 12[341]
Schedule - 36[1444]
Completed - 490[6295]
* All but completed queue applies to GBT only proposals
Current backlog [hours prior to 07A*] = 800
[2005:369(14), 2006:426(21), 2007:5(1)]
Note all 369 hrs in 2005 is for Ka, Q band projects
188 hrs (of 426) from 2006 is for Ka and Q band projects
Backlog includes 42 hrs of monitoring projects
163 hrs of vlbi projects
Total time to discharge [hours] = 5983
Includes 110 hours of monitoring after trimester 07A
3137 hours of Large proposals
970 hours of Track Refurbishment proposals
211 hours of VLBI proposals
* Includes projects that are on hold for trimester 07A
- Removed from turret:
- S,X band receivers.
- Feed Defroster
- CCB
- Prepared for Removal:
- Ka band receiver (May 8)
- C band receiver (May 15)
- Housings for C band downconverter have not returned.
Digital Group Status 28-APR-07 THRU 04-MAY-07
***Operations, Problem Summary***
Active Surface, Weather Stations, MCB, Feed Defroster, etc. (As reported by Jason Ray)...
Weather Stations...
- No additional work on the lightning detector was done due to Rusty's crew needing the manlift this week.
- We haven't looked at the WS at Weather 3 yet because it wasn't windy on Monday, it was too windy (got pulled off the telescope) on Tuesday, and it rained Wednesday and Thursday.
Active Surface...
- Got started on summer maintenance this week. Spent a day and a half diagnosing new problems in the Actuator Room. Including the leftover problems from last season, we have 36 actuators to work on this summer.
- Spent most of another part of a day rounding up motors and LVDTs to use this summer. As of last season, we've started using the parts from our spare actuator units; basically removing the LVDT and motor and leaving the rest in the shipping container. So far, we've used 23 out of the 100 spares we have. I'm thinking when we get down to ~50 full spares left I should start asking for some $$ to get some new motors made up...
MCB...
Gary reported problems getting his MCB chain in the lab working. We supplied him with two new Intelligent Converters to try. He returned two of the three as bad. Using our test setup we verified one as bad (the one that was in his system) and the other as good (the 2nd one we supplied to him) and Will report this to Gary. We're in the process of troubleshooting and repairing the bad one.
Feed Defroster...
Helped Bob Simon remove the Feed Defroster Thursday morning.
***Development***
Spectrometer LTA Re-design...
The latest round of circuit and code modifications have reduced the error rates significantly. During an overnight test using 45-second integrations into all memory locations, a total of 4,608 integrations (158,201,856 ADDER OPS) resulted in only 4 single errors. This computes to an error rate of 1 error (bad lag) per 1,152 45-second integrations (39,550,464 ADDER OPS). These tests should be wrapped up by the end of next week; at which point, the test LTA will be installed and tested in our Lab Spectrometer.
New Pulsar Backend...
With continued assistance from John Ford and the Berkeley group, Glen Langston has made significant progress toward implementation of various simple designs, including a "Pocket Spectrometer". We plan to ask for a block of time in the near future during which we can obtain interactive assistance from the Berkeley group by means of a VNC connection to our development workstation. More on this next week...
ALMA...
On-going efforts are continuing fairly smoothly on the ALMA front.
***Plans***
- Continue daily check of Spectrometer exhaust fans...
- Continue testing the first three LTA FPGA Adapter PCBAs...
- Check out operational status of lightning detector at warehouse...
- Verify wind speed data from Weather 3 and repair if necessary...
- Troubleshoot and repair MCB Intelligent Converter unit...
- Continue ALMA efforts as required...
Randy
We are in week five of the third development cycle of 2007 which can be viewed at PlanOfRecordC32007. Because we have few deliverables for the end of this cycle and these deliverables will have an isolated impact on the system, we will be patching them in as they are sponsor tested and approved with the usual emails to gbtlocal.
Operational and user support was relatively light this week and included:
- Resolved issue found after PF change to 800MHz feed. We reloaded the cabling file, and cycled the DCR Manager off and back on.
- We helped GaryAnderson track down some MCB problems in the receiver lab.
- Along with Computing, we performed a mass update of all drivers and kernels on both simulator and GBT control machines.
Modification Requests:
- MRs ready for integration/regression testing:
- MRs ready for sponsor testing:
- MRs under development:
- SCCU Servo Changes (ModificationRequest1C806)
- Although the code is working, we have found that commanded velocity spikes occur during normal observing. To date this has not been a problem since the hardware filters out the spikes. However with the hardware modifications coupled with this MR, the spikes will corrupt the intended operation of the friction compensation. John is working on modeling a different methods of deriving the velocity commands.
- MRs under CCC review:
- MRs under sponsor review:
- MRs being written:
- Other Activities:
- Dynamic Scheduling - We have finished responding to comments received on the Overview. Melinda and Mark have turned their attention from the selection rules to generating web pages to access project information. They are early on the learning curve of learning our web development framework.
- Analysis of Trajectory Generation Problems - Joe continued work on the 'new' filter style preprocessor. He also attended a servo review and subsequently submitted a list of issues which he also discussed with Tim Weadon.
- Find/Fix Command Stream Glitches - On hold pending trajectory generation problem analysis.
- Complete Pointing Processing Description Memo - No progress
- Complete Documentation of Cross-Polarization Changes - In progress.
- Evaluate GBT Data Handling Status & Future Options - In progress.
Equipment room UPS battery change proved more difficult than expected. Jerry Turner ended up having to practically dismantle the unit in situ. A spare unit is currently parked next to the old one to power the affected rack. Changeover to the old UPS is scheduled for 08:30 Monday 7th.
The gasp ds1 unit is severely dead with motherboard trouble. A plan for swapping out one of the processing nodes to restore full bandwidth has been suggested to the GASP people and I am waiting on a response.
PTCS -- PTCS Team
- Engineering
- Finished first draft of Project note describing the friction compensation mods. Sent out to project team members for review.
- Held design review on Servo Interlock System upgrade
- Astronomy
- Fred and Todd began writing the first draft of a Project note on surface modeling and holography simulations.
- Work continues on the new pointing model by Kim. The cause of the increased uncertainty in the focus terms remains unresolved. A telecon will be held next week.
I spent 35+ hours working on the 8-bit spigot mode problems this week. And while there has been some progress, the modes still don't work. There is either mis-calibration of the high 1024 lags, or there is massive dynamic range compression that removes 90% of your sensitivity if you try to run without calibration. Ryan and I have a couple other ideas to try, but currently we are taking data using the 16-bit spigot mode. Very frustrating.
MIT/LL 43m Project -- Glen
-- RichardPrestage - 03 May 2007
Revision r1.13 - 04 May 2007 - 13:23 GMT - ScottRansom
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