GBT Operations & Commissioning Meeting
AGENDA
Activities List
The first pair of base plate sections were welded together over the holiday weekend. It experienced an unacceptable twist at the weld joint, and had to be cut apart. It is being remachined today, and will be ready for re-welding Sunday.
After much analysis and measuring, a second joint was successfully welded, and a third is in progress now. Continental is gearing up to weld two at a time now, as originally planned. By Monday morning, we should have at least 4 joints welded and possibly 5. Alignment and leveling will follow for most of next week at night, and grouting operations should commence by the end of the week.
The Prime Focus Receiver will be removed from service on Monday, the Subreflector and PF systems will be out of service for two weeks, and the air conditioning system will be out of service in this building Tuesday and Wednesday.
Last 3 Weeks
=============
Observations for proposals
GBT07A-053
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 06/14/2007 - 06/28/2007
=======================================
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 ~ 518 362 500
Maintenance ~ 213 347 203
Test & Comm ~ 0 12 42
Shutdown ~ 14 0 0
Un-assigned ~ 0 0 0
Proposal Checkouts #[hrs]*
=========================
Awaiting checkout - 0[0]
Active checkout - 0[0]
On Hold - 0[0]
Schedule - 76[3661]
Completed - 491[6332]
* All but completed queue applies to GBT only proposals
Current backlog [hours prior to 07A*] = 727
[2005:369(14), 2006:358(18)]
Backlog includes 42 hrs of monitoring projects
130 hrs of vlbi projects
Total time to discharge [hours] = 5451
Includes 500 hours of monitoring after trimester 07A
3137 hours of Large proposals
490 hours of Track Refurbishment proposals
178 hours of VLBI proposals
* Includes projects that are on hold for trimester 07A
- Prime Focus and L band are in use with no problems to report.
- Increase in Rx room temperature due to chiller problems effected stability of IF system, but no failures.
- The stability returned to normal after Rx room stabilized.
- Ka band testing revealed problems associated with OMT imbalance. Solutions are being pondered, proposed.
- Ka phase switching transients coupling to bias lines continue being investigated.
- X band is cool with stability testing and characterization set to begin.
- Second C band downconverter module construction is complete and ready for test.
- Third C band downconverter module under construction with wire bonding remaining.
- Feed defroster electronic self-starter tested and working.
- Feed defroster upgrade continues with machined parts design 50% complete.
Nothing to report
Patrick Brandt has joined with Brandon Rumberg, both students of WVU
and are making good progress on the iBob firmware development.
The University of Cincinnati team has released some summary
documents and will make a presentation next week (Glen)
We have received the donated Xilinx IP modules (to the tune of about $30K worth). I am going to install these Monday, and I am going to also beg for another development system. We're running into a bottleneck there.
- Continue work on LTA upgrade
- Continue FPGA development work
- Write project charter for Advanced Digital Backends initiative
- Continue work on maintenance and repair of surface
- Fix GDAQ timestamps
Due to an air conditioning problem the feedarm servo system shut itself down.
Bob Goldizen turned it back on after the AC system was repaired.
Working with Reliance Electric to have a Field Engr to inspect our Az/El motors Thursday 6/7/07.
Working with Practec to check the calibrations of our Az/El Motor Controllers. If practical we may
have them come here to upgrade and calibrate units.
Waiting for power supply for the Spectral Processor Rack A before we get it back online.
Parts and drawings are ready for the Feed Arm Servo cabling upgrade starting next week.
Waiting for a panel, due today, to continue building the PLC upgrade for the Az/El Servo.
Will finish the Design Document for the Az/El Servo PLC upgrade this week and send it out
for review.
We are in the second full week of the fourth development cycle of 2007 which can be viewed at PlanOfRecordC42007.
Operational and user support was very light this week.
Modification Requests:
- MRs patched in to M&C this week:
- MRs ready for integration/regression testing:
- MRs ready for sponsor testing:
- Fix Accelerometer Timestamping/Data Collection (ModificationRequest2C307)
- Sponsor testing has found a clock drift which is related to sample rate. Needs a fix for the GDAQ code.
- Quadrant Detector Timestamp Fixes (ModificationRequest5C307)
- Sponsor testing has found a clock drift which is related to sample rate. Needs a fix for the GDAQ code.
- MRs under development:
- Modify Peak Finding Algorithm for Pointing/Focus Code (ModificationRequest4C207)
- Currently testing convolution approach and comparing results on datasets to approaches called out in MR.
- 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 - Work this week focused on preparation and presentation for the upcoming external review next week. Our code base to date is now under source control.
- Analysis of Trajectory Generation Problems - Nothing to report.
- Find/Fix Command Stream Glitches - Attempting to find cause/source of velocity errors.
- Complete Pointing Processing Description Memo - No progress
- Complete Documentation of Cross-Polarization Changes - Almost complete.
- Evaluate GBT Data Handling Status & Future Options - In progress.
PTCS -- PTCS Team
- Engineering
- Astronomy
- The pointing team met to define the format changes needed to implement the new pointing model (PFM5) being developed. A new track map table (and inverse table) will be read from the SQL database, and a new interpolation algorithm will be used. Aiming to begin software consistency tests by July.
- Kim is investigating whether the measured non-linearities of the subreflector encoder (currently not compensated for in the commanded positions) could account for the remaining residuals in the pointing model.
Drift scan survey seems to be going well in general. Although we've taken so much data (over 40TB so far! Yikes!) that we've almost run out of disks several times. We ordered 140x750GB disks this week, though. So that should hold us over for awhile....
Next week Ryan and I will hopefully get a chance to finish up the calibration work on the new 8-bit modes.
MIT/LL 43m Project -- Glen
Thanks to Preston, Rusty, and many of the GB site staff, the 43m transformer
was re-installed and put back in operations. The broken brake spring
was repaired on Friday. We ran tests on Friday evening
and started spacecraft tracking on Monday May 29.
Normal Spacecraft tracking is planned for this week.
-- RichardPrestage - 31 May 2007
Revision r1.13 - 01 Jun 2007 - 20:48 GMT - ToddHunter
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