From soliver at nrao.edu Fri Nov 1 15:55:57 2002 From: soliver at nrao.edu (Stacy Oliver) Date: Fri, 1 Nov 2002 13:55:57 -0700 Subject: [alma_na] [almanews] ALMA Memos 439 and 440 Released Message-ID: ALMA MEMO #439 Millimetre Wave Generation Using an Optical Comb Generator with Optical Phase-Locked Loops Pengbo Shen and Phillip A. Davies, Dept. Of Electronics, University of Kent, Canterbury William P. Shillue, Larry R. D'Addario, and John M. Payne, NRAO 2002-10-31 Keywords: Comb Generator, Photonic, lasers, LO (This memo is also presented at the 2002 International Topical Meeting on Microwave Photonics, a conference in Awaji Japan, and also appears in the conference digest) We report the generation of millimeter-wave signals to 158 GHz with phase noise better than -75 dBc/Hz at 100 kHz offset, by heterodyning of two laser which are optically phase-locked through an Optical Comb Generator. View a pdf version of ALMA Memo #439. http://www.alma.nrao.edu/memos/html-memos/alma439/memo439.pdf Download a postscript version of ALMA Memo #439. http://www.alma.nrao.edu/memos/html-memos/alma439/memo439.ps ________________________________________________________________________________________________ ALMA Memo # 440 Photonic Techniques for Local Oscillator Generation and Distribution in Millimeter-Wave Radio Astronomy 10/31/2002 John M. Payne and William P. Shillue, National Radio Astronomy Observatory Keywords: photonic, LO, photomixer {Note: This memo was an invited talk at the 2002 International Topical Meeting on Microwave Photonics, a conference held in Awaji Japan, and also appears in the conference digest. It repeats some information that has already been presented in previous ALMA memos, and is included here in the memo series because the conference proceedings are not widely distributed} A number of photonics techniques are being used for Local Oscillator (LO) generation and distribution for millimeter-wavelength radio astronomy. Many of these are being implemented or considered for use on the Atacama Large Millimeter Array (ALMA) project. View a pdf version of ALMA Memo #440. http://www.alma.nrao.edu/memos/html-memos/alma440/memo440.pdf Download a postscript version of ALMA Memo #440. http://www.alma.nrao.edu/memos/html-memos/alma440/memo440.ps _______________________________________________ Almanews mailing list Almanews at listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/almanews From soliver at nrao.edu Mon Nov 4 16:06:11 2002 From: soliver at nrao.edu (Stacy Oliver) Date: Mon, 4 Nov 2002 14:06:11 -0700 Subject: [alma_na] [almanews] ALMA Memos 438 Released Message-ID: ALMA Memo #438 Measurements of Materials for SIS Mixer Magnetic Circuits G. A. Ediss and K. Crady National Radio Astronomy Observatory 2002/11/01 keywords: magnetic materials, hysteresis measurements Measurements have been made of various magnetic materials in order to improve the flux density at the SIS junction positions in the mixer. The materials measured are Hiperco 50A, HyMu 80, Consumet iron and Magnet iron. Magnet iron is recommended for unannealed use. Consumet is recommended for annealed use. Hiperco 50A can be used annealed if large hysteresis can be accepted. For highest flux density for lowest drive current, annealed Consumet should be used. View a pdf version of ALMA Memo #438. http://www.alma.nrao.edu/memos/html-memos/alma438/memo438.pdf Download a postscript version of ALMA Memo #438. http://www.alma.nrao.edu/memos/html-memos/alma438/memo438.ps _______________________________________________ Almanews mailing list Almanews at listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/almanews From mrafal at nrao.edu Wed Nov 6 14:34:10 2002 From: mrafal at nrao.edu (Marc Rafal) Date: Wed, 6 Nov 2002 14:34:10 -0500 Subject: [alma_na] Announcement Message-ID: I am very pleased to announce that Bob Freund has been selected to fill the position of Front End Subsystem Engineer. Bob will work closely with Charles Cunningham and Gie Han Tan to help coordinate technical interactions of the various subsystems that make up the ALMA Front End. Bob brings significant expertise and his previous experience on the ALMA project will be a major asset to Front End IPT. Please join me in congratulating Bob on this new challenge. Marc Rafal -------------- next part -------------- A non-text attachment was scrubbed... Name: Freund.doc Type: application/msword Size: 24576 bytes Desc: not available URL: From tdumonde at nrao.edu Fri Nov 8 14:35:12 2002 From: tdumonde at nrao.edu (Tatiana DuMonde) Date: Fri, 08 Nov 2002 14:35:12 -0500 Subject: [alma_na] JAO/IPT meeting reminder Message-ID: <3DCC11F0.9050703@nrao.edu> Just a reminder that there is a JAO/IPT meeting scheduled for Monday November the 11th at 10:30 am EST or 1530 UTC. Hope you all will be able to attend. Sincerely, Tatiana DuMonde ALMA N.A Project Secretary From tdumonde at nrao.edu Fri Nov 8 15:26:13 2002 From: tdumonde at nrao.edu (Tatiana DuMonde) Date: Fri, 08 Nov 2002 15:26:13 -0500 Subject: [alma_na] JAO/IPT meeting reminder Message-ID: <3DCC1DE5.6080806@nrao.edu> Just a reminder that there is a JAO/IPT meeting scheduled for Monday November the 11th at 10:30 am EST or 1530 UTC. Hope you all will be able to attend. Sincerely, Tatiana DuMonde ALMA N.A Project Secretary From tdumonde at nrao.edu Fri Nov 8 16:34:19 2002 From: tdumonde at nrao.edu (Tatiana DuMonde) Date: Fri, 08 Nov 2002 16:34:19 -0500 Subject: [alma_na] Monday meeting telephone number Message-ID: <3DCC2DDB.2020402@nrao.edu> Sorry to bother you all again, but I wanted to include the telephone number for Monday's meeting: JAO/IPT Meeting: Monday, Nov, 11th 1530 UTC, 10:30am EST Telephone Number: (434) 296-7082 See you then, Tatiana From cwhite at nrao.edu Wed Nov 13 10:18:24 2002 From: cwhite at nrao.edu (Carolyn White) Date: Wed, 13 Nov 2002 10:18:24 -0500 Subject: [alma_na] ALMA Project Plan dated 2002-Oct-18 Message-ID: <3DD26D40.9010205@nrao.edu> The current ACC approved ALMA Project Plan is located at: http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/ipt1004jaomanage/showFile/100074/d20021113151040/No/ALMA_Project_Plan.oct18.pdf Please note Appendix A is not official and a revised Appendix A is in preparation for approval by the ACC. Thank you. Carolyn White (for Paul Vanden Bout) From cwhite at nrao.edu Mon Nov 18 12:19:13 2002 From: cwhite at nrao.edu (Carolyn White) Date: Mon, 18 Nov 2002 12:19:13 -0500 Subject: [alma_na] ALMA NA DH Meeting Message-ID: <3DD92111.7070907@nrao.edu> The ALMA NA DH Meeting has been canceled. Thanks Carolyn From soliver at nrao.edu Mon Nov 18 13:16:53 2002 From: soliver at nrao.edu (Stacy Oliver) Date: Mon, 18 Nov 2002 11:16:53 -0700 Subject: [alma_na] [almanews] ALMA Memos 441 and 423 Released; Revision of ALMA Memo 438 Released Message-ID: ALMA Memo #441 Enhancing the Performance of the Baseline ALMA Correlator Ray Escoffier and John Webber (NRAO) 2002/11/11 Keywords: correlator, digital filter The performance of the baseline ALMA correlator in spectral resolution can be easily and inexpensively enhanced. The time-division architecture of the system is completely consistent with the requirements of a so-called digital hybrid correlator. By replacing the present digital filter card with one of a more complex design, the spectral resolution performance of the system could be increased by factors as high as 32. View a pdf version of ALMA Memo #441. http://www.alma.nrao.edu/memos/html-memos/alma441/memo441.pdf Download a postscript version of ALMA Memo #441. http://www.alma.nrao.edu/memos/html-memos/alma441/memo441.ps ________________________________________________________________________________________________ ALMA MEMO #423 The Vane Calibration System Revisited S.Guilloteau (IRAM / ESO) 2002/05/27 I re-investigate the semi-transparent vane calibration scheme proposed for ALMA, taking into account expected saturation behavior of the receivers. This memo improves on memo 371 by using more accurate derivations and better estimates of the receiver saturation temperatures. It is shown that to reach a given precision in calibration, the saturation on the vane must be less than this precision. Suitable values for the vane transparencies are given. The vane transmission can be calibrated in a few minutes (at mm wavelengths) to 1 hour (above 275 GHz) by measurement of an astronomical source (nearby quasar). A derivation of the saturation temperature from a measurement on the vane and on an ambient load is presented. The case of partial saturation on the vane is explored. Using the derived saturation temperature in this case requires a more accurate measurement of the vane transmission, but is the only way to reach the specified accuracy. Given the simplicity of the vane system (passive, slow device, in the receiver cabin), compared with the complexity, speed and location of the dual-load system, I recommend that ALMA develops and adopts such a scheme for the receiver calibration. View a pdf version of ALMA Memo #423. http://www.alma.nrao.edu/memos/html-memos/alma423/memo423.pdf Download a postscript version of ALMA Memo #423. http://www.alma.nrao.edu/memos/html-memos/alma423/memo423.ps ________________________________________________________________________________________________ ALMA MEMO #438 Measurements of Materials for SIS Mixer Magnetic Circuits G. A. Ediss and K. Crady National Radio Astronomy Observatory Revised 2002/11/14 Original 2002/11/01 Keywords: magnetic materials, hysteresis measurements Measurements have been made of various magnetic materials in order to improve the flux density at the SIS junction positions in the mixer. The materials measured are Hiperco 50A, HyMu 80, Consumet iron and Magnet iron. Magnet iron is recommended for unannealed use. Consumet is recommended for annealed use. Hiperco 50A can be used annealed if large hysteresis can be accepted. For highest flux density for lowest drive current, annealed Consumet should be used. ALMA Memo 438 has been revised as of November 14, 2002. The new version is numbered as ALMA Memo 438.1. To view or downloaded the revised version ( November 14, 2002), please use the following links: View a pdf version of ALMA Memo #438.1. http://www.alma.nrao.edu/memos/html-memos/alma438/memo438-1.pdf Download a postscript version of ALMA Memo #438.1. http://www.alma.nrao.edu/memos/html-memos/alma438/memo438-1.ps _______________________________________________ Almanews mailing list Almanews at listmgr.cv.nrao.edu http://listmgr.cv.nrao.edu/mailman/listinfo/almanews From awootten at nrao.edu Fri Nov 22 17:34:35 2002 From: awootten at nrao.edu (Al Wootten) Date: Fri, 22 Nov 2002 17:34:35 -0500 Subject: [alma_na] ASAC Report Message-ID: <15838.45307.877585.25839@polaris.cv.nrao.edu> The ASAC Report, from their September face-to-face meeting, was presented to the group previously known as the ACC on 2002 October 30-31. The report may be obtained from http://www.cv.nrao.edu/~awootten/mmaimcal/asac/ASACSocorroReportFinal/ASACSocorroReportFinal.ps It will be posted to the usual location on the ALMA Web Pages in due course. In the Appendix to the above report on Site and Stringency there are a number of voluminous figures; a version of the report without this Appendix is also available at: http://www.cv.nrao.edu/~awootten/mmaimcal/asac/ASACSocorroReportFinal/ASACSocorroReportonlyFinal.ps and the Appendices are independently obtainable at: http://www.cv.nrao.edu/~awootten/mmaimcal/asac/ASACSocorroReportFinal/ASACSocorroReportappendices.ps Acrobat pdf versions are available at the same locations, with a file name ending in .pdf. 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 tdumonde at nrao.edu Fri Nov 22 19:18:20 2002 From: tdumonde at nrao.edu (Tatiana DuMonde) Date: Fri, 22 Nov 2002 19:18:20 -0500 Subject: [alma_na] JAO Meeting Monday 25 November Message-ID: <3DDEC94C.9050500@nrao.edu> Dear All,- This is just a reminder that there will be a JAO/IPT telecon meeting this Monday, November 25th at 1530 UTC, 10:30 AM EST. The telephone number for this meeting will be: 434-296-7082. For those of you attending in person, the meeting will be at ER conference room # 311. I had a wonderful time meeting many of you this week in Charlottesville, and look forward to hearing from you at the meeting. Sincerely, Tatiana