AMiBA Engineering Telecon Minutes

30, May, 2002

 

Participants: Australia: M.Kesteven, W. Wilson

Summary

Receiver:

1.      The noise temperature of prototype receiver no. 1 is around 100K - 120K, and no.2 is around 120k - 140K , and hopefully able to tune both receivers to the same noise level in a week or two. Mingtang got 8 db back from LNA, and it's a good result.

2.      Warwick and C.T. suggested we'd better stick with the original receiver configuration and keep on solving the 4 MHz observation on both receivers and then test the correlator together afterward, and should not jump to plan b to change the receiver configuration. Mingtang agreed with this suggestion.

As for the next run, Mingtang is trying to use a cheaper cold head - CTI 22 and MMIC amplifiers for the front end. The physical layout for receiver will be modified accordingly. Receiver interface with platform has been clarified, Bob confirmed we can enlarge the receiver hole size to 320mm.

LO/IF:

Prof. Chu is still working LO upgrading from 21GHz to 42 GHz, and hope to finish it by end - June.

MMIC:

Todd confirmed the contract for selling 28 LNA to us will be posted to RCUH by this Friday.

Correlator:

1.      Derek proposed a simplified block diagram of the reduced correlator IF distribution network. According his estimation, It will save 50% cost of the IF distribution network. He will send a jpg file to Mike to review.

2.      C.T. has tested the correlator and Marki mixer with two noise sources yesterday, but he didn't find significant change in RMS. Warwick will discuss this test further with C.T. offline to sort out the problem.

3.      Jeff updated the progress of Meridian biased mixer development, Rapadas has finished the design, and start manufacturing the housing and ordering the diodes.

Mount:

Jeff has finished the testing of the hexapod mount , and it is able to track with sub arc-sec for few minutes. He will post the test data on the web site and circulate around.

Platform:

out a 3D structure layout.

Philippe and Ted are working on the platform design, and aiming to work out all required specs and drawings for REQ by mid- July. A 3D structure layout will be worked out in week.

The interface design between mount and platform should be sorted out with Vertex ASAP.

60cm dish:

Phillip is doing FEA modeling of Miliflect option.

Jeff will send around the quote and specs of Miliflect to everyone to read and comment.

Jeff thinks it would be good if we could have two 60cm dishes on site to test together with prototype in August.

Site:

The site preparation work for prototype will be started in mid- June.

In the mean time, Bob will generate a summary of the final site specs for the MLO engineering group to begin electrical, earth work, and conctete.

Computer control:

Mike is preparing an outline of the interface specification with hexapod mount. We will proposed it at the VA PDR in August.

Action items:

1.          Mingtang/    Todd Gaier promised to send us two additional LNA, Mingtang will follow up to find out the shipping date.

2.          Mingtang/     Mingtang will use the dynamic signal analyzer to measure directly the noise of IF and LO.

3.          Mingtang/   Mingtang will come up with an action plan on prototype, so people in receiver lab could follow up accordingly.

4.          Correlator team/    The PDR on correlator will take place as soon as finish the prototype test on site.

5.          All/             C.T. has generated a work plan of "Correlator & IF distribution component development" and circulated around, please take a look and comment.

Next meeting:    Thursday, June 6 at 8:30AM Taipei time.