AMiBA Engineering Telecon Minutes

27, Jun, 2002

 

Participants: Australia: M. Kesteven, W. Wilson
  USA: B. Martin, P. Ho, D. Kubo, J. Peterson
  Taiwan: H. Wang, M.T. Chen, C.T. Li, Y.J. Hwang, H.M. Jiang, W. Ho,
    T. Huang, C,C, Han, C.J. Ma, K.Y. Lin, P. Shaw

 

Summary

Receiver:

M.T. is back here and re-start testing the receivers and calibrate the noise by using the noise source we have. Since the LO has been upgrade to 42 GHz, and Warwick will modify the software accordingly. Mingtang will test the receiver together

LO/IF:

1.      As for the IF distribution, Derek is thinking about to purchase a equalizer for cable flow, he will come up with a guess number for how much flow we need to correct. Mingtang will pass this guess number to Prof. Chu to work on the equalizer design.

2.      Derek clarify the definition of IF, the correlator IF includes the cable goes all the way to receiver, from its output is considering the correlator IF. Ther are two equalizers, one is in the receiver and  then a separate equalizer to equalize for correlator IF, the long cable basically and various components in the IF distribution.

MMIC:

1.      TRW has finalized the chip layout of InP HEMT and start making mask.

2.      Sandy Wenreb issued a letter to TRW to authorize RCUH to use his design, TRW has agreed with this authorization.

3.      Huei will follow up with Todd Gaier  on the export license issue for LNA packaging & testing.

4.      Bob is still working on the paper work for purchasing the 28 LNA from JPL.

Correlator:

1.      Derek is getting ready to order a set of amplifier for the 1st & 2nd section tentatively from Miteq. The cost is $1669 ea for the quantity of 42 , and we need to order 43 amplifiers.

2.      C.T. intends to order 120 diodes amplifiers, its cost is $70 ea.This quantity is enough for 13 elements. C.T. is looking for the local firm here to assembly these amplifiers, and we will test them in our lab.

3.      C.T. measured the snr of correlator and Marki mixer, the result is getting close with the prediction we got from the 4GHz  band-width. And with the Marki mixer, he found a lot of noise, some from ground and some from bias. He will make some arrangement to try to minimize these noise sources and test the mixer again next week. Derek got some suggestions from Mixer and forwarded to C.T. to take a look.

4.      According the test result on Marki mixer, it looks like Marki mixer isn't better than Rapadas mixer, Warwick commented. Derek suggested that may be we should go ahead to ask Rapadas manufacture 4 lag correlator, and in parallel, we could keep on developing  the mixer array and power divider .Both Jeff and Warwick agreed with this idea.

60 cm dish:

Plilippe got a quote from MAN and circulate around, its price is 325000 Euro for 7 CFRP reflector systems.

Site:

1.      The internet installation work got delay and now is scheduling for tomorrow to fix it.

2.      UPS which Derek ordered will be delivered on site tomorrow.

General:

We should keep on all other things moving without sleeping when we are working on the problem of receiver.

Action items:

1.      Derek./Mingtang/       As for the equalizer, we need a better one to meet our requirement. Derek will investigate the source in the market, and Mintang will talk to Prof. Chu about how to improve the existing design and when he can work it out. Mingtang will come up a report on this issue by next week.

2.      Derek/Bob/            Derek and Bob will figure out the length of cable we need for correlator shortly.

3.      Derek/             Derek will talk to J. Rapadas about the idea to start manufacturing the 4 lag correlator, and try to sort out the technical details.

4.      Bob/                      Bob will write up a description of emergency stop control sequence for hexapod mount and send to Mike.

5.      Bob/                 Bob will arrange a telecon with Philippe, Mingtang and Ted to go over the interface issue among receiver, platform and mount.

6.      Bob/Philippe/      We are still waiting for the FEA analysis result on Miliflect 60cm dish from Philippe.

7.      Bob/                   Bob will send the software interface document of optical telescope to Mike ASAP.

8.      Bob/                  How to install the outdoor enclosure on site, Bob will sort out the details and send to Mingtang ASAP.

9.      Mingtang/         Mingtang will figure out the shipping schedule for prototype to Hilo in two weeks. He needs sometime to fix up the stability problem.

Next telecon:     Thursday, July 4, 8:30AM Taipei time (10:30AM Sydney time, 10:30PM EST, 2:30PM Hawaii)