From tetsuo.hasegawa at nao.ac.jp Tue Sep 3 06:27:56 2002 From: tetsuo.hasegawa at nao.ac.jp (Tetsuo Hasegawa) Date: Tue, 3 Sep 2002 19:27:56 +0900 Subject: [asac]Japanese proposal Message-ID: Dear ASAC colleagues, In the forthcoming ASAC meeting in Socorro, I will present the Japanese proposal for participation in ALMA based on the attached document which has been sent from NAOJ to EACC on August 16. I hope you have a chance to look at it for a constructive discussion at the meeting. With best wishes, Tetsuo Hasegawa -------------- next part -------------- A non-text attachment was scrubbed... Name: Japanese_proposal.pdf Type: application/pdf Size: 40779 bytes Desc: not available URL: -------------- next part -------------- -- _______________________________________________________________ Tetsuo HASEGAWA, D. Sc. ALMA-J Project Scientist Professor, National Astronomical Observatory of Japan 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan Phone +81-422-34-3780 / FAX +81-422-34-3764 _______________________________________________________________ From awootten at NRAO.EDU Tue Sep 3 14:29:45 2002 From: awootten at NRAO.EDU (Al Wootten) Date: Tue, 3 Sep 2002 14:29:45 -0400 (EDT) Subject: [asac]Agenda Message-ID: <200209031829.OAA26192@polaris.cv.nrao.edu> Folks The agenda may be found at: http://www.cv.nrao.edu/~awootten/mmaimcal/asac/asacsocorroagendav1.0.html along with links to reading materials. Some of these materials are at sitescape. You will have to think Ptolemy to access these: login as almaguest and pw almaguest. ALMA is procuring more licenses so that you may have your own password soon. The antenna files are protected I see from that account. A stringency report will be added tomorrow. The aips++ report will be available on paper on Friday. The Backend PDR report is not yet available. The bus leaves for the ATF from the AOC parking lot at 3pm on Friday. Please check the spreadsheet linked to the end of the agenda for information on what NRAO-NM thinks your plans are--given the current state of the airline industry, some problems may arise; please call Christine at the phone number at the bottom of the schedule for help should your plans go awry. You may wish to print the spreadsheet and keep it handy as a guide to with whom and when you might catch a ride to Socorro should plans change. See you in Socorro! Clear skies, Al +--------------------------------------------------------+ | Alwyn Wootten (http://www.cv.nrao.edu/~awootten/) | | Project Scientist, Atacama Large Millimeter Array/US | | Astronomer, National Radio Astronomy Observatory | | 520 Edgemont Road, Charlottesville, VA 22903-2475, USA | | (434)-296-0329 voice Help us build The ALMA| | (434)-296-0278 FAX {> {> {> {> | +----------------------------------^-----^-----^-----^---+ From awootten at NRAO.EDU Wed Sep 4 11:30:01 2002 From: awootten at NRAO.EDU (Al Wootten) Date: Wed, 4 Sep 2002 11:30:01 -0400 (EDT) Subject: [asac]Upcoming ASAC Meeting Message-ID: <200209041530.LAA13491@polaris.cv.nrao.edu> Dear ASAC meeting attendee: The ASAC final agenda may be viewed at: http://www.cv.nrao.edu/~awootten/mmaimcal/asac/asacsocorroagendav1.0.html Changes since the last version: AOC colloquium at 11 am Friday added. New reading materials added: Stringency report from ASAC subcommittee. If there are further materials which you would like me to add to the list please let me know and I will distribute them. Updated spreadsheet of arrival plans. Have a pleasant journey; see you soon! Clear skies, Al From soliver at NRAO.EDU Wed Sep 4 14:50:43 2002 From: soliver at NRAO.EDU (Stacy Oliver) Date: Wed, 4 Sep 2002 11:50:43 -0700 Subject: [asac][almanews]ALMA Memo 432 Released Message-ID: ALMA MEMO #432 A Split-Block Waveguide Directional Coupler A. R. Kerr and N. Horner National Radio Astronomy Observatory Charlottesville, VA 22903, USA 2002/08/26 Keywords: Directional couplers, Waveguide couplers, Millimeter wave directional couplers, Millimeter wave circuits. A simple waveguide directional coupler is described which uses the split-block type of construction common in millimeter-wave components. The coupler uses an array of metal probes suspended on quartz stand-offs. Depending on the number of coupling elements, the coupling can be in the range 15-30 dB, with typically ? 2 dB variation across the waveguide band, and directivity > 10 dB. The coupler, intended for injecting local oscillator power into a waveguide mixer, can be scaled for operation in any waveguide band. View a pdf version of ALMA Memo #432. http://www.alma.nrao.edu/memos/html-memos/alma432/memo432.pdf Download a postscript version of ALMA Memo #432. http://www.alma.nrao.edu/memos/html-memos/alma432/memo432.ps _______________________________________________ Almanews mailing list Almanews at listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/almanews From awootten at NRAO.EDU Thu Sep 12 10:48:06 2002 From: awootten at NRAO.EDU (Al Wootten) Date: Thu, 12 Sep 2002 10:48:06 -0400 (EDT) Subject: [asac](no subject) Message-ID: <200209121448.KAA05671@polaris.cv.nrao.edu> Dear ASAC Meeting Presenter: On behalf of the project scientists, thank you very much for the presentation you delivered to the ASAC meeting in Socorro. I believe that the meeting was quite successful. The Committee is currently working on its report. Stacy Oliver has set up an area for the meeting materials (http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/almaprojmeetings/showF older/100217). Please place your presentation there; this will assist the ASAC as they preprare their report to the ACC and it will document the meeting. The main document that you will want to upload is the pdf version of your presentation. The powerpoint version should just go in as an attachment. If you would like to enter these items, please just take a look at the area at the above link and you will find two folders. The first is for the agenda and other materials and the second is for the presentations. To put items in, you just use the regular "add" button and then select the "submit document link". Fill in whatever fields apply. If you have questions, just contact Stacy Oliver (soliver at nrao.edu). Again, thanks for your participation in this fruitful meeting. Clear skies, Al From soliver at NRAO.EDU Thu Sep 12 16:01:09 2002 From: soliver at NRAO.EDU (Stacy Oliver) Date: Thu, 12 Sep 2002 13:01:09 -0700 Subject: [asac][almanews] ALMA Memos 420 and 433 Released Message-ID: ALMA MEMO #4203 Digital Transmission System Signaling Protocol Robert W. Freund (National Radio Astronomy Observatory) 2002/09/06 Keywords: signaling protocol, digital protocol, digital transmission, parallel data transmittion, optical fiber communication, data scrambling, virtual parallel bus, OC-192, VPB The ALMA Digital Transmission System (DTS) transmits digitized IF signals from an antenna to the correlator at the central location. The digitized data is divided equally across four identical transmission elements. Each element formats the parallel data for serial transmission over three 10 Gb/s optical fiber channels and converts it back into parallel data at the receiver. This Virtual Parallel Bus (VPB) system is defined by the channel signaling protocol. The protocol is based upon a 160-bit frame structure using line coding employing scrambling techniques. The frame consists of a nchronization word, a sequence word, payload, and a checksum. Modulo-2 addition of the frame with a pseudo random pattern scrambles the data to provide adequate recovery timing information and a reduction of low frequency content. View a pdf version of ALMA Memo #420. http://alma.aoc.nrao.edu/memos/html-memos/alma420/memo420.pdf Download a postscript version of ALMA Memo #420. http://alma.aoc.nrao.edu/memos/html-memos/alma420/memo420.ps ________________________________________________________________________________________________ ALMA MEMO #433 2002: The Driest and Coldest Summer R. Bustos (CBI Project) 2002/09/06 This memo reports NCEP/NCAR Reanalysis results for the southern hemisphere summer of 2002 (December 2001 - March 2002). The data shows a very low amount of PWV as well as low temperatures, indicating that it has been the driest and coldest summer for the last 50 years. The results confirm the previous conclusions about interannual variability of PWV during the austral summer and that there is no climatological trend of increasing PWV for the Chajnantor area. The Reanalysis data of the surface temperature shows a decrease in average temperatures during the last three years. A direct relationship between the fraction of time when winds from the east are present and the average amount of PWV is also obtained. As we have previously shown there are two different seasons with different origins at the site: the summer (mid-December to mid-March) is related to a change in the region's circulation and presents a high amount of PWV with the presence of easterly winds, and the winter (April to November) is more related to ENSO and the Pacific Ocean activities. View a pdf version of ALMA Memo #433. http://alma.aoc.nrao.edu/memos/html-memos/alma433/memo433.pdf Download a postscript version of ALMA Memo #433. http://alma.aoc.nrao.edu/memos/html-memos/alma433/memo433.ps _______________________________________________ Almanews mailing list Almanews at listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/almanews From soliver at NRAO.EDU Mon Sep 16 19:06:29 2002 From: soliver at NRAO.EDU (Stacy Oliver) Date: Mon, 16 Sep 2002 16:06:29 -0700 Subject: [asac][almanews] ALMA Memos 434 Released Message-ID: ALMA MEMO #434 Load Calibration at Millimeter and Submillimeter Wavelengths Jeff Mangum (NRAO Tucson) 2002/09/12 Keywords: Calibration Accurate amplitude calibration at millimeter and submillimeter wavelengths is a difficult goal to achieve due to the temporal variability of the emissive and absorptive properties of the Earth's atmosphere and the lack of an accurate astronomical flux standard. The difficulties with deriving a uniform amplitude calibration system has resulted in the three step calibration process used at millimeter and submillimeter single dishes and interferometers. The second step in this process involves the chopper wheel calibration technique. Chopper wheel calibration is used to derive the antenna temperature of an astronomical source corrected for atmospheric extinction. An analysis of the uncertainties in three variants of this technique, two which use a single calibrated load and a third which uses two calibrated loads, has been derived. The conclusion of this analysis is that the one-load chopper calibration systems are more uncertain than the two-load chopper calibration system. This is especially true at submillimeter wavelengths. The main reason for the larger uncertainty of the one-load chopper calibration systems is the fact that they require a knowledge of the mean atmospheric temperature, which is inherently difficult to obtain. Of the two calibration systems, the two-load chopper system has the potential for reaching a calibration accuracy of approximately 1% for all bands, as specified for the ALMA receiving systems. View a pdf version of ALMA Memo #434. http://alma.aoc.nrao.edu/memos/html-memos/alma434/memo434.pdf Download a postscript version of ALMA Memo #434. http://alma.aoc.nrao.edu/memos/html-memos/alma434/memo434.ps _______________________________________________ Almanews mailing list Almanews at listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/almanews From soliver at NRAO.EDU Wed Sep 25 17:41:18 2002 From: soliver at NRAO.EDU (Stacy Oliver) Date: Wed, 25 Sep 2002 14:41:18 -0700 Subject: [asac][almanews] ALMA Memos 435 Released Message-ID: ALMA Memo # 435 A Hybrid Option for the First LOs using Direct Photonic LO Driver M. Ishiguro, Y. Sekimoto, A. Ueda, S. Iguchi, T. Noguchi (NAOJ) J. M. Payne, L. R. D'Addario, W. Shillue (NRAO Tucson) 15/09/2002 Keywords: Local Oscillator, Photomixer, Frontend We propose a hybrid option for the first local oscillators (LOs) of ALMA in which a direct photonic LO driver is used to drive cold multipliers. The photomixer using NTT uni-travelling carrier photodiode has been demonstrated to have high power of 2 m W at 100 GHz and low amplitude noise of $< 7 - 17$ K/$\mu$W in the frequency range of $98 - 105$ GHz. This option simplifies the LO part of the cartridge in the baseline ALMA and retains a future possibility for a direct photonic option. View a pdf version of ALMA Memo #435. http://alma.aoc.nrao.edu/memos/html-memos/alma435/memo435.pdf Download a postscript version of ALMA Memo #435. http://alma.aoc.nrao.edu/memos/html-memos/alma435/memo435.ps _______________________________________________ Almanews mailing list Almanews at listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/almanews