| INSTRUMENT MENTOR MONTHLY SUMMARY REPORT |
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Return to a list of available MMCR summariesIMMSNo 3387 loaded
| Source: MMCR | Report Date: 07/2009 |
Instrument Mentor Monthly Summary Report for MMCR: 07/2009
1. Data Review:
No problems.
Uptime: 100%
NSA
No data: 7/12/2009 2200 – 7/13/2009 0500
Uptime: 98.9%
Manus
Bad data: 7/1/2009 0100 – 7/3/2009 0230
No data: 7/8/2009 0230 – 0245
No transmit: 7/22/2009 0130 - 2359
Uptime: 90.3%
Darwin
No problems.
Uptime: 100%
2. Instrument Performance Issues and Trends:
The precip mode is still a problem and investigation continues. PIF P081029.1 was submitted for this.
PIF 081216.1 A major problem with the MMCR’s hardware (PIRAQ-III) and software (LAP-XM) was discovered. The result of this problem is that the receiver protection circuits do not protect the receiver. This can result in damage to the LNA. A software fix was written and BCR-01526 covered the installation of this patch. This has resulted in approximately a loss of 3% of the radar’s efficiency, i.e. there is 3% less data that before the patch. Once the Nauru MMCR is received at PNNL, I will explore a hardware change to the pulse controller that will return the MMCR to full efficiency.
SGP
We will not attempt a refurbishment of the 10’ antenna. A new antenna is being procured. For more information, see discussion on ECO-00551 below.
Open DQRs
D050714.4 – Poor cross polarization isolation – this will be solved with a new antenna when it is received back from the vendor.
NSA
The instrument shelter (“Great White”) experienced excessive heating and this caused the MMCR to shut down on 7/12/2009 and 7/13/2009.
Open DQRs
D080430.1 – Reflectivities too high. This is becoming harder and harder to understand since all components of the radar have been individually calibrated and no anomaly has been found.
Manus
The MMCR occasionally locks up in a mode that does not produce good data. This is the only MMCR that exhibits this particular problem. Rebooting remedies the problem.
Open DQRs
D080604.3 – Reflectivities too high
Darwin
Still minor problems associated with Labview error window. No data loss due to this problem. I spent some time on this again and tried comparing processes that are running on the Darwin computers but not on the other MMCRs where this problem occurs. A few programs were found and removed with no affect.
Developmental MMCR (at PNNL)
The MMCR from Nauru has been received at PNNL with the exception of the antenna. It was immediately unpacked to prevent as much salt corrosion as possible. Installation has begun.
3. Current Task Status:
ECO-00575 Study Network Transfer of MMCR and WACR Spectra to Archive
The images of filtered vs. unfiltered spectra moments are available at:
http://c1.dmf.arm.gov/data/process/sgp/sgpmmcrspecmaskC1.a0/
Additional sites will have this feature if/when bandwidths to those sites (Barrow and Manus) are increased.
ECO-00658 MMCR – end-to-end calibration analysis
ProSensing (Jim Mead) is performing a comprehensive analysis of both the MMCR and WACR to validate each radar’s calibration process. My comments have been submitted back to ProSensing. Since the SGP 10’ antenna won’t be recharacterized, ProSensing will be wrapping up the report in the next few months.
Very Important
ECO-00552 BARROW MMCR – Polarization Upgrade
This ECO is still on hold pending the resolution of the calibration and dc issues on the Barrow MMCR.
ECO-00551 MMCR Antenna Refurbishment
Millitech has determined that they cannot handle the 10’ antenna at their range. They sought out other ranges and found two, both owned by the US Air Force. The cost to have our current 10’ antenna at SGP characterized was excessively expensive. I queried a select group of the ARM Science Team to get their opinion on how to proceed with the options being:
1. Spend the additional $66K and keep the original plan.
2. Don’t do the initial characterization and go directly to refit. There is risk here if the main reflector is a contributor to the cross-pol isolation problem. As far as gain goes, we are pretty comfortable with the gain based on comparisons last year with the WACR.
3. Buy a brand new antenna and forget about refurbishing the old antenna. This still costs us $33K more than originally budgeted.
4. Forget the 10’ antenna altogether and buy a new 6’ antenna. This will result in a loss of 4 dB of antenna gain and an increase in beamwidth of 0.1 degree. One might argue that we would have a shift in sensitivity, which is true. However, we have had many shifts in sensitivity since the MMCR was first installed with improvements in signal processors and a 3 dB increase in transmit power.
The consensus was overwhelmingly to go with option #3. ACRF management agreed with this and this is how we are proceeding.
Both 6’ antennas for the TWP (Darwin and Manus) are at SGP and awaiting shipment to their proper destinations.
4. Near-Term Plans:
Install new 6’ antenna at Manus (tentatively rescheduled for September 2009).
Install new 6’ antenna at Darwin.
Install the Nauru MMCR antenna at PNNL when it arrives.
Investigate coatings to apply to the radomes so that they will shed water/snow more effectively.
Analyze PARSIVEL and POSS data and compare with MMCR from Barrow.
5. Accomplishments: