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GET /hyperkitty/api/list/[email protected]/email/SGUAU5BJOJYQ4CZORMU3BCHBWJQJLQEW/?format=api
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/SGUAU5BJOJYQ4CZORMU3BCHBWJQJLQEW/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "BA9AF80FA64F4CF2B856ECC6AE106103@laptopmatthias", "message_id_hash": "SGUAU5BJOJYQ4CZORMU3BCHBWJQJLQEW", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/D2SHA7WJAIRVODYBTP5GLMVGFY32GAMK/?format=api", "sender": { "address": "matthias.bopp (a) gmx.de", "mailman_id": "8e98db3953494c5f92cac72f4aa25f2c", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/8e98db3953494c5f92cac72f4aa25f2c/emails/?format=api" }, "sender_name": "Matthias Bopp", "subject": "[amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ", "date": "2009-05-19T11:10:18Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/K5SZGURD5QEIDTLA5T3VSUF54HJDT6LO/?format=api", "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Hi Art,\n\nthis is a very good point. This is also one of the reasons why circular\npolarization was chosen for the commercial GPS system.\n\nBest regards\n\nMatthias\n\nwww.dd1us.de (including many soundfiles of AMSAT satellites)\n\n\n-----Ursprüngliche Nachricht-----\nVon: Art McBride [mailto:[email protected]] \nGesendet: Dienstag, 19. Mai 2009 07:50\nAn: 'Matthias Bopp'; [email protected]\nBetreff: RE: [amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ\n\nOne important feature of circular to circular antenna reception is the 30 dB\nof rejection of signals that are opposite polarity from ground and building\nreflections that will cause QSB on linear antennas used for reception. If\nyou are 30 miles out to sea this is not a concern.\nArt,\nKC6UQH\n\n-----Original Message-----\nFrom: [email protected] [mailto:[email protected]] On\nBehalf Of Matthias Bopp\nSent: Sunday, May 17, 2009 7:38 AM\nTo: [email protected]\nSubject: [amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ\n\nHi Luc,\n\na linearly polarized antenna on a satellite means, that you will see\ndifferent polarization at different times and different locations on\nEarth. Assume the satellites transmit vertical polarization but \"tumbles\"\nthen the polarization you are receiving is always linear but can vary\nbetween vertical, diagonal, horizontal ...\nTherefore it is better if the satellite and the station on earth both use\ncircular polarization. If this is not possible due to constraints on the\nsatellite I think it is still better to have a circular polarized antenna\nat my station as the losses due to varying linear polarization will always\nbe only 3dB and thus no strong fading due to polarization will accur.\nPlease note that a tumbling satellite will most likely still generate strong\nfading as the antenna on the satellite will never have a perfect\nomni-directional behaviour.\n\nBest regards\n\nMatthias DD1US\n\nwww.dd1us.de\n\n\n-----Ursprüngliche Nachricht-----\nVon: [email protected] [mailto:[email protected]] Im\nAuftrag von Luc Leblanc\nGesendet: Sonntag, 17. Mai 2009 14:09\nAn: [email protected]\nBetreff: [amsat-bb] Re: Gain VS Bandwidth at 2.4GHZ\n\nOn 16 May 2009 at 17:27, Roger Kolakowski wrote:\n\nA part of my mystery is solved WiFi and WiMAX I am not a big fan of WiFi as\ni have some security concern but i discover that i don't have \nthe best antenna for 2.4 and fiddling with it is not an option. A true 2.4\nis in the mail to replace it and with 2 antennas now i will be \nable to install them to have vertical and horizontal polarisation and i will\nsee if there is some improvement at 2.4ghz when switching \nbetween them. Nobody answer me back regarding the S band linear \"not\ncircular\" AO-51 antenna but the fades are probably due to some \nantenna blocking than anything else. On the last S band session me and Clare\nVE3NPC noted that the fades does not happen at the same time \non our respective QTH there is surely not some selective circular\npolarisation path?\n\n> This was probably just a typo; if so, pardon the reply...\n> \nI was mixing both...hi \n> \n> Wi-Fi and Wi-Max are different things. An antenna designed for Wi-Max\n> may not operate very well, as you describe, on 2.4 ghz. Wi-Fi's\n> 802.11b/g is on 2.4 ghz (channel 1 is right on top of our allocation),\n> so a properly designed Wi-Fi antenna could be good for 13cm Ham\n> applications.\n> \n> >\n> Enjoy the new toy,\n> \n> Greg KO6TH\n> \n\nSome experimenting to come on the next S band session.\n \n\"-\"\n\n\nLuc Leblanc VE2DWE\nSkype VE2DWE\nwww.qsl.net/ve2dwe\nWAC BASIC CW PHONE SATELLITE\n\n \n\n_______________________________________________\nSent via [email protected]. Opinions expressed are those of the author.\nNot an AMSAT-NA member? Join now to support the amateur satellite program!\nSubscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n\n\n_______________________________________________\nSent via [email protected]. Opinions expressed are those of the author.\nNot an AMSAT-NA member? Join now to support the amateur satellite program!\nSubscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n\n__________ Information from ESET NOD32 Antivirus, version of virus signature\ndatabase 4081 (20090517) __________\n\nThe message was checked by ESET NOD32 Antivirus.\n\nhttp://www.eset.com\n\n\n \n\n__________ Information from ESET NOD32 Antivirus, version of virus signature\ndatabase 4081 (20090517) __________\n\nThe message was checked by ESET NOD32 Antivirus.\n\nhttp://www.eset.com\n \n\n__________ Information from ESET NOD32 Antivirus, version of virus signature\ndatabase 4085 (20090519) __________\n\nThe message was checked by ESET NOD32 Antivirus.\n\nhttp://www.eset.com\n \n \n\n__________ Information from ESET NOD32 Antivirus, version of virus signature\ndatabase 4085 (20090519) __________\n\nThe message was checked by ESET NOD32 Antivirus.\n\nhttp://www.eset.com\n \n\n\n", "attachments": [] }