DRAFT Notes from telecon to discuss OSF Holography. July 29th, 13:00 UTC. Participants: Eduardo Donoso, Darrel Emerson, Jorg Eschwey, Brian Glendenning, Clint Janes, Jeff Mangum, Rick Murowinski, Antonio Perfetto, Dick Sramek, Al Wootten. AGENDA: 1. Progress on Action Items 2. Any Other Business. ACCOUNT OF MEETING: Before we launched into a discussion of Action Items, Rick pointed out that as part of the antenna vendor discussions, it had been agreed that holography would be performed on the 1st antenna on the contractor pad. Our technical installation would be closer to the contractor's assembly building. It has also been agreed that our holography system would be used to measure the eventual Mitsubishi antenna too. The suggestion had come up that our holography transmitter be put on a nearby mountain peak, rather than on a tower at our site. This is what APEX have done, and it seems to have worked for them. This would give us a higher antenna elevation angle for the measurements, and the transmitter would further towards (but not yet in) the far field region. Although this would avoid purchasing a tower, and would probably avoid the need to make the transmitter antenna steerable, it might nevertheless be more expensive. There is no road up to any nearby mountain site. Power would need to be provided (probably solar), some form of remote control would be needed, with a higher gain transmitter feed, and possibly higher transmitter power. Cerro Negro seems to be the most likely site for such an installation. Standalone system: Rick mentioned that there is pressure to make the holography setup independent of everything else, a standalone system. Action item: Jorg agreed to come up with a document estimating the cost and difficulty of using a mountain site, compared to a tower within our compound. This document would be available within about 5 weeks. PREVIOUS ACTION ITEMS (from minutes of the previous telecon): (i) Antonio will arrange for the new holography feeds, and make a budgetary estimate in a very short timescale. (ii) An overall block diagram will be created by System IPT, making use as far as possible of existing material. [System IPT hasn't yet been given the opportunity to agree to this.] (iii) Environmental issues: Eduardo will list what will eventually be required to allow the tower. (iv) Tower siting: Eduardo and Darrel will work on this together, using a detailed local terrain model. Budgetary revision for the 50-meter height to be made by Eduardo. (v) Antonio will work on the holography receiver temperature regulation issue. (vi) Darrel will endeavour to clarify who is responsible for the antenna holography cabling. (vii) The decision on holography adopting the ALMA data format needs to be disseminated. A responsibility of Systems? (viii) The intention to test the revised holography system at the ATF should be disseminated. Systems. (ix) The new holography transmitter is to be designed and built by Antonio. (x) Rick Murowinski will work with Darrel (Rick doesn't know this yet) to produce the needed schedule and milestone for all these, and other, activities. CURRENT PROGRESS on PREVIOUS ACTION ITEMS: i) Antonio said about another 2 weeks is needed for the estimate. Ability to measure the new feeds in GB needs to be confirmed. Rick mentioned that another holography receiver has been requested for the Japanese 7-meter antennas. Rick will find out what design parameters may be different for that system. ii) Dick estimated another 2-3 weeks for the block diagram. iii) Eduardo reported that no formal permission is needed to erect the 50-meter tower within our compound; we just need to inform the authorities. If we install something on any nearby mountain peak, then permission must be sought. Eduardo will find out what's required for this. iv) Tower siting. Eduardo and Darrel are working from a terrian plan for the siting, but recent discussions with the antenna contractor may influence this. v) Antonio said that antenna elevation pointing would influence the temperature regulation issue, so this could be different for a mountain transmitter site. Rick said that for now we should continue our planning as before, assuming that we would NOT be using a mountain transmitter site. Antonio asked if dual frequency holography is still needed. Jeff Mangum agreed to investigate that issue. vi) The site group is responsible for all cabling other than on the antenna. The AIV group is responsible for the holography cabling on the antenna itself. For the very first antenna measurement, some less than permanent arrangement would be acceptable. vii) Brian announced that the holography data would be written in the ALMA data format. Robert Lucas would take care of whatever changes are required in the current holography data analysis system to ensure compatibility with this. ix) Antonio is working on the new holography transmitter design. x) Schedule and milestone plan. Rick has already preduced the first version of this plan. This needs to be updated, and Rick will work with Antonio and others to keep it current. It does currently show some slack time, but this could easily disappear with any unexpected delays. AOB Clint Janes asked about a holography ICD to interface to the backend. Rick replied that, as we are trying to make the holography system a standalone system independent of the backend, such an ICD is not needed. NEW ACTION ITEMS: a) Antonio continues to work on estimates for the holography hardware. For now this will assume we are NOT changing our baseline plan of putting the transmitter on a 50-m tower within the OSF compound. b) Dick continues with the system block diagram. As in (a), the assumption continues that we'll be using a tower in our compound. Delivery of system diagram about 2-3 weeks. c) Jorg is making an estimate of what it would take to put a transmitter on a nearby mountain peak. Antonio will provide the needed technical information. Timescale for estimat about 5 weeks. d) Jeff Mangum will look at the APEX holography measurements. Reflections may be an issue - would this be better or worse with a mountain-top transmitter? Do we need 2 frequencies? Communicate with the rest of the group, but especially to Antonio. e) Tower siting, assuming there will be a tower. Darrel continues to work with Eduardo. f) Brian will make sure Robert Lucas knows about the new holography data format. Robert will adapt his analysis software to this. g) Dick Sramek will put into the PSI plan, the intention to test the revised holography system at the ATF. h) Schedule and milestone plan. A continuing task, but Rick will in particular get better information from Antonio. i) For everyone: another telecon to confirm progress will be held in about one month (i.e. end of August).