Antenna Working Group Update, Oct96

Peter Napier, Chair

Minutes of MMA Antenna Working Group Meeting, 25 Sep 1996.

This phone meeting was attended by J.Cheng, D.Emerson, J.Lugten, P.Napier, J.Payne and D.Woody. The agenda included a discussion of the new optics layout for the antenna and initial analysis of the gravitational performance of the reflector with new F/D and quadruped support location. Main points of discussion: (1) There was agreement that the new optics layout for the antenna would be a primary F/D of 0.38 and a secondary F number of 9.3. Subreflector diameter and central blockage have a diameter of 18.9 in. This geometry allows close packing of 1.285D at 19.5 deg and 1.348D at 0 deg elevation. Jeff will produce a sketch of the overall optics layout which will be given to the Receiver working group for their acceptance. The receiver group will have to choose between one of several possible feed arrangements, including off axis feeds, a rotating dewar to locate the observing feed on axis or a cooled flat reflector. (2) Jingquan's initial calculations on reflector gravitational deflection are confusing as to the relative importance of primary F/D, reflector depth and quadruped support location. Jingquan will carry out a systematic analysis of the importance of these three parameters.

Agenda for MMA Antenna Working Group Meeting, 23 Oct 1996.

The next meeting of the MMA antenna working group will be a phone meeting on 23 Oct at 1400 (PDT and Tucson), 1500 (MDT) and 1700 (EDT). Phone number is 201 872 3134. The agenda for the meeting will be: (1) Discussion of the new optics layout drawing to be given to the receiver group (drawing will be faxed to you). (2) Results from gravitational rms computations for new reflector design. (3) Current status of new design.

Last modified 22 Oct 96