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{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/CUMKLFL6MXEK75WNQJQ4A2XQ6Y4RQW4P/", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/", "message_id": "[email protected]", "message_id_hash": "CUMKLFL6MXEK75WNQJQ4A2XQ6Y4RQW4P", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/CUMKLFL6MXEK75WNQJQ4A2XQ6Y4RQW4P/", "sender": { "address": "dale_potts (a) hotmail.com", "mailman_id": null, "emails": null }, "sender_name": "Hacken Paste", "subject": "[amsat-bb] Re: [Re: Prospero] Commanding Error", "date": "2011-10-28T10:19:25Z", "parent": null, "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "\nHi Roger,\n\n\n\nI think only 8 of the OrbComm satellites are on 137.56.. It sounds like \nit may be worth contacting OrbComm though- I'll give them a call.\n\n\n\nDale\n\n\n\nOn 28/10/2011 10:39, [email protected] wrote:\n\n\n\n \n\nHi Roger,\n \nAll understood..I have put the currently 28? active Orbcomms into Nova here \nand almost all of the time there is at least one above my horizon and I \ncan hear the chuffing noises..will be listening again this evening\n \nDo you have details of the on board power system? For instance what \nare the batteries? If the batteries have failed short circuit will they be \nclamping the bus to 0volts? Can the power system work with open circuit cells? \nWhat is/was the default power up operating mode? \n \ngood luck!\n \nGraham\nG3VZV\n\n\n \n\nFrom: Roger Duthie \nSent: Friday, October 28, 2011 10:25 AM\nTo: Tony Abbey \nCc: [email protected] ; [email protected] ; Phil Guttridge ; \[email protected] ; [email protected] \n; Dale Potts \n; Barry Hancock \n; Richard Cole ; mailto:[email protected] ; Alan Smith ; Graham Kimbell \n(G3TCT) \nSubject: Re: [amsat-bb] Re: [Re: Prospero] Commanding \nError\n \nOK \n- so that's definitely Orbcomm (from the spectrogram). Have you got audio \nof this? \n\nWe hear a chuffing sound intermittently (ie., it comes \nand goes in interval of minutes), which happens when neither Orbcomm nor \nProspero is reported by our software to be above the horizon (is this the pager \nstuff you're talking about?). We also heard another thing a couple of days \nago, though we're still not 100% on what that might have been (it appeared to be \nfading as Prospero receded to the North - though was it an aeroplane on \n137.56?).\n\nSomeone yesterday has supposedly heard something that's wasn't \nOrbcomm during the early evening pass. We'll look into it.\n\nThe pass \nwe're going to try today (for the sake of ceremony, really) is (again, times in \nBST = UT + 1):\n\n\n\n \n \n 28 \n Oct\n 7.4\n 15:53:18\n 10\n S \n 16:00:22\n 86\n W \n 16:08:28\n 10\n N \n- Roger\nm0rja\n\nTony Abbey wrote: \nHi Roger \n \n \n Once Graham told me the noise was Orbcomm this morning, I added the TLEs \n for their satellites (http://www.orbcomm.com/Collateral/Documents/English-US/o11292.tle)\n to my SDR Radio software satellite definitions. Here's a pass I recorded \n from one of them this morning, and you can see that the \"chuff-chuff\" on the \n left hand side has structure which is kept vertical by the doppler correction. \n The other crap and pager cross talk etc bends with the doppler correction. I \n think that proves the point.\n \n \n \n \n \n Tony Abbey - Senior \n Research Fellow (retired)\n \n Space Research Centre\n Dept of Physics and Astronomy\n University of LeicesterUniversity Road SRC Web page: http://www.src.le.ac.uk \n LEICESTER LE1 7RH, United \n Kingdom\n \n Spectrogram removed by RJAD (might ahve been bad for the amsat-bb board)\n\n \n\n \n\n \n \n \n On 27 Oct 2011, at 16:17, Roger Duthie wrote:\n \n We're hearing these 'chuff-chuff \n swooshes' too, though at times when our software is not showing Orbcomm over \n our horizon. Our TLEs may be slightly out-of-date, though I think it \n would be a marginal thing. Can it be definitely confirmed that these \n noises are Orbcomm?\n\n- Rr.\n\nTony Abbey wrote: \n Nothing heard from Prospero here in Leicester, that pass just \n finished (at 14:57Z) \n Just the Orbcomm swooshes.\n \n \n \n \n \n \n Tony Abbey - \n Senior Research Fellow (retired)\n \n Space Research Centre\n Dept of Physics and Astronomy\n University of LeicesterUniversity Road SRC Web page: http://www.src.le.ac.uk \n LEICESTER LE1 7RH, United Kingdom\n \n \n \n \n On 27 Oct 2011, at 13:33, Roger Duthie wrote:\n \n Well, we're hearing something like \n that. Though we hear this a lot, we also wonder whether we''re \n seeing an envelope during the Prospero pass times. \n\nThe \n passes for today (BST) [from Heavens-Above]:\n\n \n \n \n 27 Oct\n 7.2\n 15:42:26\n 10\n S \n 15:49:21\n 77\n E \n 15:57:21\n 10\n NNE\n \n 27 Oct\n 8.7\n 17:28:31\n 10\n WSW\n 17:34:45\n 31\n WNW\n 17:41:39\n 10\n N \nAlso, I've started a Twitter hashtag \n for anyone using this mode of communication: #Prospero40 Add this \n to any Twitter messages you might write about Prospero or related \n subjects.\n\n-Roger\n\nPE0SAT wrote: \n Hi,\n\nI have a spectrogram and a recording of that \"chuff chuff\" on\nhttp://www.pe0sat.vgnet.nl/satellite/sat-history/prospero/\n\nIs it the same you guys heard?\n\n73 Jan PE0SAT\n\n\nOn Thu, October 27, 2011 10:04, [email protected] wrote:\n \n Hi Tony,\n\nThe chuff chuff noises are from space...they are a sort of beacon carried\non\nevery Orbcomm satellite. They are 125msec long pulses of 57.6kb data and\nhave a bandwidth of around 50kHz. They are quite distinctive when you only\nhear one at a time but sometimes one can hear two or more signals at the\nsame time and that sort of changes the sound:)\n\n73\n\nGraham\nG3VZV\n\n-----Original Message-----\nFrom: Tony Abbey\nSent: Wednesday, October 26, 2011 8:56 PM\nTo: [email protected]\nCc: Phil Guttridge ; [email protected]\nSubject: [amsat-bb] Re: [Re: Prospero] Commanding Error\n\nHi Roger\n\nNothing other than the chuff- chuff on the 1600 pass. And as you said, its\nalso there with Prospero over the horizon. I 'm not using a beam presently\n-\nusing a 360deg parasitic Lindenblad for circular polarisation, but it is\nsusceptible to all the high power pager stuff nearby. Its just strange\nthat\nthere are elements shifting in frequency in the chuff chuff like a signal\nfrom a real satellite.\nHave just come back from a Rosat re-entry celebration!\n\nTony Abbey - Senior Research Fellow (retired)\nSpace Research Centre\nDept of Physics and Astronomy\nUniversity of Leicester\nUniversity Road SRC Web page: http://www.src.le.ac.uk\nLEICESTER LE1 7RH, United Kingdom\n\n\n\n\n\nOn 26 Oct 2011, at 16:17, Roger Duthie wrote:\n\n \n Tony -\n\nWe heard something intriguing after about 14:43:40 UT as the tracking\nsaid\nthe satellite was on it's way off to the north pole.\n\nThe 'chuff-chuff' description reminds me of a sound we seem to hear\nquite\na lot. Quite often it coincides with a pass, though I think we hear the\nsame (or very similar) during times when Prospero is over the horizon.\n\nWe are going to try the next pass at ~16:00UT if you want to listen in\nagain. Our new ploy is to wait for the last most opportune moment to\ncommand, as the power _may_ be at it highest (longest charging of\nbatteries, potentially). So, we'll do short commanding at above 30o el,\nand listen.\n\n-Rr.\n\nTony Abbey wrote:\n \n Hi Roger\n\nI could hear some \"chuff-chuff\" noises on the last pass and they show a\nrelated doppler shift (although I am not correcting sufficiently) as\nyou\ncan see in the attached plot. Maybe its some other noise but you never\nknow.\n\nOn 26 Oct 2011, at 13:39, Roger Duthie wrote:\n \n Commanding went well, from as far as we could make out. We're not\nsure\nif we're getting anything back, however.\n\nWe'll be doing this pass today, hopefully:\n\n26 Oct 7.3 15:31:43 10 S 15:38:26 60 E 15:46:11 10 NNE [Times in BST =\nUTC + 1]\n\n-Roger\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_______________________________________________\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\n\n\n\n\n \t\t \t \t\t ", "attachments": [] }