High Frequency Program Coordination Meeting Minutes 12aug02 Attendance: Brian Mason, Phil Jewell, Nicole Radziwill, Richard Prestage, Dennis Egan, Galen Watts, John Ford, Roger Norrod I. 3mm & 1cm Rx -BM gave an overview of the noise diode calibration scheme, which others will go digest. With what we know now this approach seems to make sense; the cost (for 3mm -- 1cm already has the parts) is ~ $16.9K, and a 4 Kelvin penalty in Tsys (to one arm of each radiometer). -RN presented project timelines. The 1cm Rx is slated to be ready for testing in mid-March, with full integration on the telescope (with the CIT Continuum Backend) by mid-May. The 3mm Rx will be ready for testing in July 2003, with integration on the telescope slated for fall/winter 2003. RN's timelines show M&C work beginning in October/November, and NR is happy with this (although at some point we may need to think about our priorities in relation to to other projects, eg the pulsar spigot card) -RN on behalf of MS gave an update on 3mm Rx progress. Room temperature OMT testing has given good results, and plans in a cryostat will be conducted soon. MS is pursuing the possibility of a MMIMIC 2nd stage amp (instead of the originally planned 1st stage-like HFET) with Eric Bryerton of CDL; if this pans out, compression properties of the RF amplifiers is going to be less of an issue. This together with end-of-year procurement are MS's top priorities for this month. -GW gave a 1cm Rx update. Procurement is complete; we also have the continuum multiplexer/filter boards in house and ready for testing. The prototype phase switch assembly is wirebonded and ready for testing. As we are nominally breaking new ground here some iteration may occur, although we don't expect any serious problems. A current bottleneck is electroforming/plating at CDL. -It was pointed out that we will probably want to support a DCR interface to these two receivers, and some thought needs to be given to this. II. CIT Continuum Backend -Many thoughts were expressed, and BM will gather these into a coherent form for the Caltech group to include in a revised proposal/design, for review early in September. Overall, it was agreed that the basic design was sound and well-thought out. Chief Amongst the comments: *A detailed discussion of the strategy for RFI mitigation is missing in the current draft, and this is very important. *We should continue to do the differencing in hardware *TTL + 1 PPS is ok *16 bit data acquisition is ok, implying a T_ant=485 K limit at 30 GHz and T_ant=1080 K at 90 GHz. *The arrangement of having the CIT CBE be master of the switches (when it is operational) is ok. We note that this carries the penalty that we cannot use the continuum backend in conjunction (simultaneously) with any other Rx. Some thought should be given in the implementation to being able to swap fairly rapidly between this and another backend. *The CIT CBE should not be involved in the receiver monitor & control functions that are run over the MCB. *Better software boundaries are needed; in particular, the suggested decoupling from YGOR does not seem like a good or feasible thing. We will commit to provide the Caltech group with a skeleton control manager, and if necessary arrange visits to work closely with MCS, in order that they are able to deliver a control manager based on the YGOR libraries. *The current command protocall looks too much like others we've not had good experiences with-- we need to be sure proper handshaking & two-way communication goes on, rather than 1 way commanding only. *There is some confusing and erroneous discussion of strong source problems which should be deleted. More detailed comments will also be channeled. -We should suggest an early September meeting so both JF & NR can attend (tentatively: Fri Sep 6). -PJ needs to have the paperwork started by this time early September, and the critical thing for this is that we have an accurate price estimate. The key factors which may change the estimate from the current figure are the RFI mitigation, and the requirement for spare parts which we should add to the MOU. III. Penn Bolometer Array -BM is working on developing algorithms for wide-field imaging with the array; due to mechanical constraints there is unlikely to be the typical nodding/chopping degree of freedom, and this drives the approach to the analysis. A visit with the experts will be helpful, and PJ/RP will contact them to arrange Edinburgh and Cardiff visits as possible. -DE reports that the test cryostat was completed and shipped off to Penn today. IV. PTCS -RP presnted a summary. EMS tests were conducted last week, and many data were gathered which are being analyzed; data were also taken at S-band to test the correlation of quadrant detector data with astronomy data, although maybe the S-band primary beam is too big for this to have been useful (further tests at X are scheduled). Analysis of this is also in progress. Due to other priorities, no progress on the feedarm lasers (surface) is likely this winter, so Q band commissioning will have to do with what we've got. More measurements at K (and eventually Q) are needed to reliably understand what we've got (and these measurements are likely to be more helpful than holography). V. Other -JF reports the tipper hardware is fixed, as is the software. -The phase monitor fix is awaiting parts.