Notes for V2C telecon, Nov. 21, 2013 ------------------------------------ In attendance: Chris Beaudoin, Brian, Corey, Ruediger Haas, Dan MacMillan, Arthur Niell, Bill Petrachenko, Mamoru Sekido Mixed-mode discussion --------------------- It was generally felt that the mixed mode document served a useful purpose. eMail comments and discussion from the telecon will be incorporated. It was suggested that the document be split into two sections, the first being a summary of "mixed mode issues" and the second being the "action plan". It was recommented that the sumary be submitted as aV2C memo and that the action plan be uploaded to the Wiki where it can evolve. Correlator and Data Transmission Requirements --------------------------------------------- John agreed to prepare schedules to help evaluated these requirements at milestones in the "VGOS Observing Plan" document and Dan agreed to do simulations to evaluate performance at those milestones. Bill agreed to help be more specific with the schedule and simulation requirements. These are tasks for the start of 2014. It was also pointed out that Toni Searle may, at the level of 10%-20%, be available to help with some of this work. It was suggested that, since VieVS is not fully operational, that SKED be the preferred tool. Status Reports -------------- Ruediger: The good news is that an archaelogical consultation concluded that sensitive areas not near current Twin Telescope Onsala preferred sites. As a result, they are ready to re-apply for a building permit. It appears that, due to higher surface accuracy requirements for the Kokee antenna, the cost of the Intertronics antenna his risen to $1.3M which is unwelcome news for those hoping to build a low cost site. This does not include the hexapod. The possible benefits of an axial actuator were discussed. Mamoru: At NICT the 3-14 GHz fixed frequency system broadband is progressing. Two of their small (~1.6 m) antennas have been tested with the 32 m Tsukuba and 34 m Kashima dish in a single polarization X-band configuration. The high band >6 GHz side of the Kashima broadband front end will be ready for test in December. At GSI, Ishioka will be ready for broadband tests in the second quarter of 2014. In 2015 and 2016 the tri-band feed will be used to establish geodetic ties to Tsukuba. Mamoru questioned whether VGOS considers using broadband (512 MHz or 1024 MHz) channels. It was answered that VGOS will use narrow channels (32 MHz) because of concerns about RFI, but will be interested to hear about the NICT experience with wide channels. Dan: Work continues with Ericos Pavlos on SGP simulations, with a focus on reconciling differences between Calc/Solve and Geodyne. Chris: Work continues on a new delay calibrator unit. Instabilities were traced to ferrites which were removed. Some longer term drifts however still remain, e.g. +/- 1ps over 10's of seconds. Brian: Work continues evaluating broadband data, in particular multiband differences between the polarizations. Differences in PCAL may be the cause. In addition old-style cable units are being evaluated as an interim solution until new units are ready. The work has halted for the lack of a test system. It might be possible to use one currently at GGAO. Arthur: Work continues on the analysis of the May data, in particular combining all four bands and both polariations in a coherent fit. There are systematic phase residuals accross the full RF band the perhaps could be removed using something like manual PCAL. The work is helping to debug new features in FOURFIT. Next telecon: Dec. 19 -------------