Calibration Group Phone Telecon Meeting Minutes  -  2003-Oct-09

Attending: Butler, Carter, DiFrancesco, Hills, Holdaway, Mangum, 
   Pintado, Radford, Sterling, Welch, Wright, Wootten (apologies to 
   anybody I missed)



 - Project news.  Al summarized results from the Correlator CDR.  The 
   major change is to replace the polyphase filters with completely
   tunable ones, ameliorating the aliasing problem at the subband edges
   and allowing for more tuning flexibility.  Overall the correlator
   seems to be in very good shape.

   The AMAC will meet next week in Holland.  Al does not have to go,
   as Ewine will make the Science IPT presentation.
   The ALMA Board will meet in Santiago on November 3-4.  Ground 
   breaking will occur on November 6.  The road from the site to the
   OSF (and thence to the highway) is nearly complete.

 - Al then started the discussion on the amplitude calibration widget.
   ALMA week (Victoria) miscommunication resulted in the S/T vane tests
   on the 30-m being suspended.  A new contract to continue this 
   testing (between ESO and IRAM) is being finalized - hopefully it 
   will be signed by Monday October 13 (according to Matt).  The 
   testing will include finishing up tests on the current S/T vane 
   device (notably doing real astronomy on the sky).  It will then
   progress to a new wire grid system with multiple loads, and finally, 
   the full-up system described in memo 461 will be designed and tested.
   Different couplers (S/T vane, wire grid, dielectric film 
   beamsplitter) will also be tested on the final device.  Eventually, 
   the complete ALMA system, with real front ends, dewar, etc..., will
   be tested at the OSF in late '05/early '06.  This has necessitated 
   several WBS changes (with a formal CRE request from Al).  The 
   testing plan and formal CRE are linked from the agenda.  Between 
   Matt and Jesus-Martin, the telescope time will get scheduled 
   somehow.  Bryan pointed out that we still might get some relief on 
   the amplitude calibration requirement from the ASAC (see notes from
   2003-Sep-15 telecon on this).  We will not know until the ASAC 
   report comes out after the ALMA Board meeting (Nov. 3-4).

 - Bryan then started the discussion on the calibration plan document.  
   He expressed some dismay at the lack of response to the October 1 
   deadline for folks to have drafts of their contributions in.  Only 
   BB and Jack had contributed anything substantial.  He suggested that
   all leaders should attempt to have at least crude drafts in by 
   October 15.  If we can at least have a unified draft by the end of 
   the month, this would be good progress.  Al pointed out that this 
   document should be compatible with the Science Requirements document,
   but did not necessarily need to agree with the System Design
   document that Larry D'Addario is working on currently.

 - Mark then discussed the new memo by he and Larry.  It considers 
   sensitivity loss due to opacity as well as decorrelation.  It does 
   not include sensitive imaging simulations.  Richard pointed out that 
   these effects should be baseline dependent, i.e., the electronic 
   noise will show up on short baselines more often than Larry and Mark 
   have assumed (95% of the time things are limited by atmosphere).  
   Mark pointed out that the fast switching effective baseline is 100m. 
   Mark and Richard agreed that the treatment of the effects as a 
   function of baseline length should be explicit.  Further discussion 
   on this topic is warranted, and could perhaps be a topic in a Science
   IPT telecon.

 - Richard then introduced Alison Sterling, who is a new member of the 
   Cambridge group working on WVR issues.  Her background is a 
   combination of meterology and astronomy - well-suited to the task
   at hand.  She was welcomed by all.

 - Al pointed out that the job announcement for Bryan's ALMA position 
   had been released internally at NRAO, and had received two responses.
   He will be doing interviews in the near future.  This new person
   could conceivably start by the end of the year.  If no qualified 
   internal candidate is found, the announcement is made to the outside 
   world, and the timescale will be longer.

 - We discussed briefly our next telecon.  Bryan pointed out that it's
   probably not appropriate for him to run these telecons any more, 
   given that he's no longer formally employed by ALMA.  Al agreed,
   and somebody else will take over this responsibility.

dutifully scribed by bjb with input from haw on 2003-Oct-13.