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GBT Operations & Commissioning Meeting

24th August 2007

AGENDA

• Upcoming Activities -- Carl
• Az Track, Antennae Report -- Bob
• Observing News -- Toney
• Scheduling Status -- Carl
• Microwave Electronics Status -- Steve
  • Operations
  • Development
• Digital Electronics Status -- Randy
• Servo Systems Status -- John and Tim
  • Operations, Problem Summary
  • Development
• Software Status -- Amy
  • Operational & User Support
  • Modification Requests/Tasks
• Computing -- Chris
• PTCS -- PTCS Team
• Pulsar Related -- Scott
• MIT/LL 43m Project -- Glen
• Commissioning Plans -- Toney
• Any other Business

Upcoming Activities -- Carl

Az Track, Antennae Report -- Bob

The "fat lady" has arrived at the concert hall, and is warming up!

We also had a field work kick-off meeting with Harris Fire Protection of Baltimore, MD, who will furnish and install the fire protection systems in each of the rooms on the telescope. This work will likely occur in late September or October, and we'll have to coordinate some maintenance days to fit this in. Some components will require RFI evaluation/shielding, which will have to be done before installation.

Painting continues through next week. The stairs are being re-installed and painted now, and after grating is put down, should be available for service next week.

Bob Goldizen and the mechanics have gone through almost all of the servo system motors, and should finish up next week as well.

Provided the azimuth track work necessary to permit motion is completed as outlined above, the first week in September marks the return to dynamically scheduled maintenance days for the high frequency observing season.

Observing News -- Toney

With PF1 out of commission, we did not do any observing this past week. With the delay in getting PF1 fixed it is unlikely that we will do any observing during the next week. We are open to suggestions of tests, etc. that can be performed during this time.

Scheduling Status -- Carl

Microwave Electronics Status -- Steve

Operations

• Prime Focus amplifier that was repaired is also an oscillator.
• Another amplifier is being installed this week for a targeted August 30 installation.
• Q band has a high noise (~70-80% excess) in channel L1 and must be removed for trouble shooting.

Development

• C-band downconverter: 2 units are 90% tested and seem to be well matched, and meeting all specs. A third unit is working fine, except it's gain is about 6db lower than the other units. Work continues on it.
• Ka Band:During Trx and Tcal measurements it was determined that feed one may have resonances at or about 35.9, 36.2 and 36.5 GHz, leading to Trx values of 103, 212 and 100 K respectively. If not feed resonances there is probably a waveguide joint with a gap or possibly debris in the waveguide. The receiver will be warmed and problems investigated.

Digital Electronics Status -- Randy

***Operations, Problem Summary***

No significant events to report this week.

***Maintenance***

Active Surface...

No work was done on the Active Surface this week.

***Development***

CICADA (Advanced Digital Backends Program)...

• The project charter for our Next Generation Common User NRAO Pulsar Backend Project (AKA Scott Ransom's "Dream Pulsar Machine") has now been placed on our CICADA wiki.
• Jason Ray and I expect to begin work on Phase 1 of the NGCUNPB project early next week.
• A formal specifications document for the NGCUNPB will be placed on our CICADA wiki for review and approval next week. All approvals are expected to be received by no later than 04-SEP-07.

Spectrometer LTA Re-design...

• The 2nd LTA card is now undergoing its upgrade and testing. It's expected to be re-installed in the GBT Spectrometer by the middle of next week; thus completing the LTA upgrade for Quadrant 0.
• FPGA Adapter cards for the next two LTAs (Quadrant 1) have already been partially built and await their FPGAs (which require removal of the LTAs from the Spectrometer). This is expected to happen around the middle of next week as well.

ALMA...

On-going efforts are continuing fairly smoothly on the ALMA front.

***Plans For Next Week***

• Continue accelerated GBT Spectrometer LTA upgrade program...
• Begin work on NGCUNPB project, Phase 1
• Continue ALMA efforts as required...

Randy

Servo Systems Status -- John and Tim

Operations, Problem Summary

Development

We found that the azimuth limit switches are not functioning. The azimuth redundant limit switches are the only ones keeping us from going through the wrap. We verified this under normal configuration also. This will be investigated early next week. (It appears we have some type of latent error.)

Software Status -- Amy

We are in the sixth development cycle of 2007. Please see the PlanOfRecordC62007 for all of the division's assigned activities.

Operational & User Support

Operational and user support was very light this week.

Modification Requests/Tasks

• MRs ready for release:
• MRs ready for sponsor testing:
  • Implement PFM5 revised pointing/focus model (ModificationRequest1C407)
    • Note - This MR was released as part of M&C v7.5 to simplify sponsor testing. PTCS is actively working on testing numerical results using test program created as part of MR.
• MRs under development:
  • Port Holography Manager to Linux (ModificationRequest1C307)
    • Alpha version of Linux manager is working. Building simulated data stream against which to perform more thorough testing, per MR.
  • Modify Peak Finding Algorithm for Pointing/Focus Code (ModificationRequest4C207)
    • FrankGhigo and ToddHunter have settled on GaussianFilter as preferred method. However, since this approach changes the resultant pointing offset values, deployment of the selected approach will be postponed until after the new pointing model is implemented this summer.
  • 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 ready for sponsor signature:
  • Correct Labeling of Ka-band Hybrid-Switched Signals (ModificationRequest3C407)
    • MR written and reviewed, starting official signature process.
• MRs being written:
  • Add DIO interface to Linux Holography Manager (ModificationRequest12C507)
    • Revising MR to reflect recent team discussion about interrupt characteristics of new interface card, and the effects this will have on software design.
  • Control of Subreflector Nodding by Astrid (ModificationRequest2C407)
    • The sponsor has completed the requirements' sections, the software engineers need to fill in the design and testing sections. No issues seem to be raising their heads so we expect getting signatures should go smoothly.
  • Subreflector Nodding Observing API Building Block (ModificationRequest17C507)
    • One small issue remains and the signature process can begin.
  • Ka Manager Changes (ModificationRequest1C507)
    • GalenWatts is working on MR.
  • Create Pyrgeometer Manager (ModificationRequest2C207)
    • No progress.
  • Mustang Manager (MasterMustangManagerMr)
    • Lots of project management related activities this week. We got IRC working with the 2.6 Linux kernel. We received 2 additional DFB cards. We can now go back to our original testbed configuration which will help us in our testing of the YGOR Manager.
  • Data File Stream Upgrade (ModificationRequest7C507)
    • No progress this week.
• Tabled MRs:
  • Add Two New ScanTypes: FivePoint and Circle (ModificationRequest1C706)
• Other Activities:
  • Complete Pointing Processing Description Memo - Work being performed as part of implement model 5 task above. Needs some cleanup to include focus tracking.
  • Dynamic Scheduling - Mostly project management related activity this week.
  • Create SRS for PST Administrative Functionality - We are iterating with Carl to refine requirements. Carl is away on vacation this week.
  • Evaluate GBT Data Handling Status & Future Options - No work this week because Bob focused on Ka work this week.
  • Mustang Support - We are providing support as needed.
  • PTCS Support - Currently working on subreflector sampler data drop-outs and retesting subreflector actuators. Joe has tracked this down to a problem with the timestamp coming from the SCU. Not certain of the cause yet.

Computing -- Chris

The UPS that failed during the power outage last week has been replaced.

The new cisco switches for the servo room have now arrived, only a few small parts are still required. Installation planning can proceed once these are available.

PTCS -- PTCS Team

• Servo
• Pointing
  • Validation of the M&C implementation of PFM5 took a big step forward this week. We have good agreement in all the terms (gravitational, track-related, and hysteresis) between Kim's processing and Joe's pointingTestUtility. However, the sign convention for the lambda2 term needs to be checked and agreed on. Also, a question has arisen on the equations of the azimuth thermal correction. While this does not impact the validation process, it is important to resolve.
  • A project management page has been written for the 2007 Pointing project.
• Holography
  • A draft project note on "GBT Holography Simulation and Analysis of Lunar Scans" by Schwab and Hunter has been released for comments. We are distributing it in bound hardcopy form as the .ps file is 100's of MB. If we haven't given you one and you'd like to read it, please let us know.

Pulsar Related -- Scott

MIT/LL 43m Project -- Glen

• not so normal spacecraft tracking; We've had some antenna servo faults of unknown origin. Tim W. is looking into it.
• No success in GPS pointing tests on Monday night. The wrong spacecraft trajectories were provided.
• Will re-run GPS tests Monday August 27, in the afternoon and astronomy tests that night.
• Working with Eric Phelps, on Real-Time trajectory mode specification. Will write this up after the space VLBI meetings.

Commissioning Plans -- Toney

It was decided that we will go with the single polarization per beam version of the Ka-band receiver.

The PF1 receiver replacement amp turned out to also be defective. Gary will take his time to make sure the PF1 receiver gets done correctly. Gary forsees no problems with working on Q-band and PF1 at the same time. The only possible issue is the sharing of lab test equipment between Ka, Q and PF1 work.

K-band is currently scheduled to be cooled next week.

At present there does not appear to be any impact on the commission schedule from the delay in PF1.

• July 17 through Aug 1 : L-Band refrigerator work. Must be completed for Governor's school
• Aug 1 through Aug 31 (originally Aug 17, the end of track shutdown) : Reinstall Q-band; pump and cool.
• Aug 6 : Install Mustang
• Aug 6 through no later than Sept 7 : Mustang tests
• By Aug 13 (Originally Aug 10) : Decision as to whether we will use this fall the one polarization configuration of Ka-band.
• By Aug 10 (1 week before end of track shutdown) : Install S-band and X-band. The receivers will already be cold when they are installed. Due date is set by the end of the track repairs and so may slip forward or backward. Installing by Aug 10 is preferable since that will give us time for receiver checkouts during the track shutdown.
• By Aug 31 (originally Aug 17, the end of track shutdown) : receiver checkouts for S-, X-, and Q-band. Includes pulsar checks of new S-band filters. Two nighttime 4 hr sessions per week, the LST is to be determined.
• Aug 27 Remove Q-band from telescope to investigate high Tsys in one channel.
• Aug 31 - Sept 15 (originally Aug 17 - Aug 30, the end of shutdown to 2 weeks later) : Contingency test time for any remaining S-, X-, and Q-band receiver checkouts. One nighttime 4 hr sessions per week. Dynamically scheduled.
• Aug 31 (originally Aug 17, the end of track shutdown) : start of PTCS recommissioning of the track
• No later than Sept. 3 : K-band pumped and cooled
• No later than Sept. 10 but no sooner than 1 week after K-band is cold: K-band receiver checkout. Dynamically scheduled.
• No later than Sept 7 : Mustang removed
• Sept 14 : End of PTCS recommissioning of track
• Week of Sept 17 or Sept 24 : Install Ka-band. Contingent on Aug 10 decision.
• Before Sept 24 : Ku-band removed to make room for Zpec. No need to cool Ku until it is reinstalled (Nov?). Contingent on Aug 10 decision.
• Week of Sept 24 or Oct 1: Install Zpec. Contingent on Aug 13 decision.
• Week of Sept 24 : Q-band project checkout (8 hrs)
• Sept 23 - Sept 30 : SDD software tests for Oct 3 release
• Week of Sept 24, Oct 1, and Oct 8: Ka-band/Spectrometer recommissioning. Contingent on Aug 10 decision. One 8 hr sessions per week of A-class weather (nighttime, dynamically scheduled).
• Week of Sept 24: Re-install Q-band and do receiver checkout.
• Week of Sept 24, Oct 1, and Oct 8: Ka-band/Spectrometer recommissioning. Contingent on Aug 10 decision. One 8 hr sessions per week of A-class weather (nighttime, dynamically scheduled).
• Oct 1 - Oct 13 : Zpec commissioning, A and B weather, dynamically scheduled. Contingent on Aug 10 decision.
• Oct 7 - 15 : CCB/Ka testing, A-class weather (nighttime, dynamically scheduled).
• No later than week of Oct 15 : Install C-band .
• Oct 18 : Decision as to whether to continue using the Ka-band single-pol configuration. Whether to schedule 100 hrs of Zpec observing. Whether to remove Ka and convert back to old configuration. Whether to proceed with Ka/Spec/CCB observing.
• Oct 21-Nov 2 : C-band astronomical commissioning, C-class weather
• Nov 2 : C-Band observing can start
• Nov 2 : Decision on how to proceed with traditional holography. Which receiver will we remove? When will tests start? Do we need to cut a mounting plate?
• Nov 2-15 : C-band baseline tests, C weather, and X-band baseline tests, B weather, dynamically scheduled.
• Week of Dec 3 : C-band removed, Mustang installed
• Dec 7 : Telescope at access for Mustang
• Dec 8 - week of Jan 15 : Mustang tests -- dynamically scheduled, A weather, nighttime.
• Week of Jan 21 : Mustang removed, C-band installed
• Feb 3-13: SDD software tests for Feb 13 release

Any other Business

• Space VLBI tracking station planning meeting next week, on August 29 and 30. All are invited to attend.

-- RichardPrestage - 23 Aug 2007