Notes from Commissioning Coordination Meeting 18 October 2002 1. Antenna News Richard reported on the status of the investigations into the feedarm behavior. Meetings were held during the week with the GB antenna group and with Lee King and Fred Schwab. A battery of tests were planned for the weekend. These included a "yield test," in which the antenna is driven repeatedly to elevations of 15 and 85 degrees, and a target on the feedarm is measured with the ground-based surveying instruments. This will indicate whether there are any permanent deformations occurring. Another set of resonant frequency tests with the accelerometers will also be performed. The data will be reduced over the weekend and Monday, and a decision of whether to resume operations will be made at the conclusion of the analysis, which is expected on Tuesday. [As has been previously reported, this analysis was completed and gave no indication of problems in the feedarm, and operations were resumed on Tuesday.] 2. K-band Commissioning Plan Richard reported on the plan that Ron has developed for K-band commissioning. The plan calls for the majority of K-band commissioning to be completed by the end of this year. Most observing capabilities for frequencies below 26.5 GHz should be commissioned and available at this milestone. Q-band commissioning would begin in the winter, with completion in the spring. The PF2 Receiver will not be commissioned until February under this plan. The K-band commissioning plan will be discussed again at the next meeting. There are some software requirements to be defined, principally in the handling of multi-IFs. Ron is working on a memo describing these requirements in detail that should be available on Thursday, the 24th. Jim Braatz noted that a limitation he experienced in K-band observing last spring was the lack of good pointing calibrators. Phil noted that millimeter-wave pointing lists may be of use for this purpose. [N.B. There is a nice list of mm-wave pointing sources in the IRAM 30 Meter Observers Manual, Appendix D. The manual is on-line as a postscript file at http://iram.fr/PV/veleta.html. I will print a few hardcopies of the list for Jim and commissioners.] 3. Spectrometer Status Rich and Holly were doing Spectrometer tests at meeting time, so Rich sent the following report by email: An updated spectrometer status spreadsheet was placed on the web yesterday. A paper copy has been left with Phil. In short, many 200 MHz and 800 MHz modes were tested in the past week and most looked OK to me. I have forwarded those to Rick for his evaluation. A few modes looked liked they had problems which I have attributed to multi-bank software problems. Some work was done trying to understand the effects of blanking on the spectrum. This still needs work. Immediate plans are to optimize the LTA read out delays, which should remove the small 1024 long lag bumps in the auto-correlation functions. 4. Software Status Report Nicole sent the following report: o We are ending week 3 of a 5 week development cycle. o All of our projects are still green. o Next week is for validation and testing in preparation for M&C v3.8 release on 10-30-02. o Only caveat pertains to Spectrometer Multibank: When deployed on 10-30, it may work most of the time, but not all the time (~90%). We will be working hard through the validation period next week to improve this prior to deployment. o A regular status printout will be available on the web on Monday. 5. K-band Spectral Baselines Roger gave a presentation on K-band baselines. The K-band receiver has been in the Equipment Room, directly connected to the IF down-conversion rack. Data were taken by looking at one receiver channel at a time, with 5 minute integrations and 20 second dumps. About two hours of data were taken. One channel looked pretty good, but another showed problems. There is some evidence that the problem may be associated with LO blanking. Also, if the first scan was used as a reference for a series of scans that followed, the 70 MHz ripple was evident. This ripple has been seen with other receivers and with the IF rack noise source. 6. AIPS++ News Joe M. reported that Bob had been working to optimize the van Vleck correction in the Filler. The speed of the correction itself has been improved by about x10, and the overall speed of the Filler by x2. Glen has been helping with a documentation review. The list of defects has been revised and refined. The averaging and decimation routines have also been worked on. A memory leak has been found and fixed. The GBT link to AIPS++ has been rationalized and will point to the current Stable in the future. Joe and Athol plan to meet with Richard and Phil to finalize the next 6-month development cycle plan for Dish. PRJ // 24 Oct 2002