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{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ROWBK7KEYMKI5YTND527GVOJUC4QFZOT/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "[email protected]", "message_id_hash": "ROWBK7KEYMKI5YTND527GVOJUC4QFZOT", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/HJMBUACI76CR6J42TUK2EC77JEF5KNQ6/?format=api", "sender": { "address": "afa3 (a) leicester.ac.uk", "mailman_id": null, "emails": null }, "sender_name": "Tony Abbey", "subject": "[amsat-bb] Re: [Re: Prospero] Commanding Error", "date": "2011-10-27T16:02:37Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/5NB3GE7TLWZZO63DH7WO3TD7IMUVPDH4/?format=api", "children": [ "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ZZUR7HI5BILNKOCYBKDNDDE5NG3MC4N7/?format=api" ], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Hi Roger\n\nOnce Graham told me the noise was Orbcomm this morning, I added the TLEs 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 from one of them this morning, and you can see that the \"chuff-chuff\" on the left hand side has structure which is kept vertical by the doppler correction. The other crap and pager cross talk etc bends with the doppler correction. I think that proves the point.\n\nTony Abbey - Senior Research Fellow (retired)\nSpace Research Centre\nDept of Physics and Astronomy\nUniversity of Leicester\nUniversity Road \tSRC Web page: http://www.src.le.ac.uk \nLEICESTER LE1 7RH, United Kingdom\n\n\n\n\n\nOn 27 Oct 2011, at 16:17, Roger Duthie wrote:\n\n> We're hearing these 'chuff-chuff swooshes' too, though at times when our software is not showing Orbcomm over our horizon. Our TLEs may be slightly out-of-date, though I think it would be a marginal thing. Can it be definitely confirmed that these noises are Orbcomm?\n> \n> - Rr.\n> \n> Tony Abbey wrote:\n>> \n>> Nothing heard from Prospero here in Leicester, that pass just finished (at 14:57Z)\n>> Just the Orbcomm swooshes.\n>> \n>> Tony Abbey - Senior Research Fellow (retired)\n>> Space Research Centre\n>> Dept of Physics and Astronomy\n>> University of Leicester\n>> University Road SRC Web page: http://www.src.le.ac.uk \n>> LEICESTER LE1 7RH, United Kingdom\n>> \n>> \n>> \n>> \n>> \n>> On 27 Oct 2011, at 13:33, Roger Duthie wrote:\n>> \n>>> Well, we're hearing something like that. Though we hear this a lot, we also wonder whether we''re seeing an envelope during the Prospero pass times. \n>>> \n>>> The passes for today (BST) [from Heavens-Above]:\n>>> 27 Oct\t7.2\t15:42:26\t10\tS\t15:49:21\t77\tE\t15:57:21\t10\tNNE\n>>> 27 Oct\t8.7\t17:28:31\t10\tWSW\t17:34:45\t31\tWNW\t17:41:39\t10\tN\n>>> Also, I've started a Twitter hashtag for anyone using this mode of communication: #Prospero40 Add this to any Twitter messages you might write about Prospero or related subjects.\n>>> \n>>> -Roger\n>>> \n>>> PE0SAT wrote:\n>>>> \n>>>> Hi,\n>>>> \n>>>> I have a spectrogram and a recording of that \"chuff chuff\" on\n>>>> http://www.pe0sat.vgnet.nl/satellite/sat-history/prospero/\n>>>> \n>>>> Is it the same you guys heard?\n>>>> \n>>>> 73 Jan PE0SAT\n>>>> \n>>>> \n>>>> On Thu, October 27, 2011 10:04, [email protected] wrote:\n>>>> \n>>>>> Hi Tony,\n>>>>> \n>>>>> The chuff chuff noises are from space...they are a sort of beacon carried\n>>>>> on\n>>>>> every Orbcomm satellite. They are 125msec long pulses of 57.6kb data and\n>>>>> have a bandwidth of around 50kHz. They are quite distinctive when you only\n>>>>> hear one at a time but sometimes one can hear two or more signals at the\n>>>>> same time and that sort of changes the sound:)\n>>>>> \n>>>>> 73\n>>>>> \n>>>>> Graham\n>>>>> G3VZV\n>>>>> \n>>>>> -----Original Message-----\n>>>>> From: Tony Abbey\n>>>>> Sent: Wednesday, October 26, 2011 8:56 PM\n>>>>> To: [email protected]\n>>>>> Cc: Phil Guttridge ; [email protected]\n>>>>> Subject: [amsat-bb] Re: [Re: Prospero] Commanding Error\n>>>>> \n>>>>> Hi Roger\n>>>>> \n>>>>> Nothing other than the chuff- chuff on the 1600 pass. And as you said, its\n>>>>> also there with Prospero over the horizon. I 'm not using a beam presently\n>>>>> -\n>>>>> using a 360deg parasitic Lindenblad for circular polarisation, but it is\n>>>>> susceptible to all the high power pager stuff nearby. Its just strange\n>>>>> that\n>>>>> there are elements shifting in frequency in the chuff chuff like a signal\n>>>>> from a real satellite.\n>>>>> Have just come back from a Rosat re-entry celebration!\n>>>>> \n>>>>> Tony Abbey - Senior Research Fellow (retired)\n>>>>> Space Research Centre\n>>>>> Dept of Physics and Astronomy\n>>>>> University of Leicester\n>>>>> University Road SRC Web page: http://www.src.le.ac.uk\n>>>>> LEICESTER LE1 7RH, United Kingdom\n>>>>> \n>>>>> \n>>>>> \n>>>>> \n>>>>> \n>>>>> On 26 Oct 2011, at 16:17, Roger Duthie wrote:\n>>>>> \n>>>>> \n>>>>>> Tony -\n>>>>>> \n>>>>>> We heard something intriguing after about 14:43:40 UT as the tracking\n>>>>>> said\n>>>>>> the satellite was on it's way off to the north pole.\n>>>>>> \n>>>>>> The 'chuff-chuff' description reminds me of a sound we seem to hear\n>>>>>> quite\n>>>>>> a lot. Quite often it coincides with a pass, though I think we hear the\n>>>>>> same (or very similar) during times when Prospero is over the horizon.\n>>>>>> \n>>>>>> We are going to try the next pass at ~16:00UT if you want to listen in\n>>>>>> again. Our new ploy is to wait for the last most opportune moment to\n>>>>>> command, as the power _may_ be at it highest (longest charging of\n>>>>>> batteries, potentially). So, we'll do short commanding at above 30o el,\n>>>>>> and listen.\n>>>>>> \n>>>>>> -Rr.\n>>>>>> \n>>>>>> Tony Abbey wrote:\n>>>>>> \n>>>>>>> Hi Roger\n>>>>>>> \n>>>>>>> I could hear some \"chuff-chuff\" noises on the last pass and they show a\n>>>>>>> related doppler shift (although I am not correcting sufficiently) as\n>>>>>>> you\n>>>>>>> can see in the attached plot. Maybe its some other noise but you never\n>>>>>>> know.\n>>>>>>> \n>>>>>>> On 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\n>>>>>>>> sure\n>>>>>>>> if we're getting anything back, however.\n>>>>>>>> \n>>>>>>>> We'll be doing this pass today, hopefully:\n>>>>>>>> \n>>>>>>>> 26 Oct 7.3 15:31:43 10 S 15:38:26 60 E 15:46:11 10 NNE [Times in BST =\n>>>>>>>> UTC + 1]\n>>>>>>>> \n>>>>>>>> -Roger\n>>>>>>>> \n>>>>> _______________________________________________\n>>>>> Sent via [email protected]. Opinions expressed are those of the author.\n>>>>> Not an AMSAT-NA member? Join now to support the amateur satellite program!\n>>>>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n>>>>> \n>>>>> _______________________________________________\n>>>>> Sent via [email protected]. Opinions expressed are those of the author.\n>>>>> Not an AMSAT-NA member? Join now to support the amateur satellite program!\n>>>>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n>>>>> \n>>>>> \n>>>> \n>>>> \n>>>> \n>>> \n>>> -- \n>>> ---\n>>> Roger J A Duthie\n>>> PhD Candidate\n>>> Plasma Group\n>>> Department of Space & Climate Physics\n>>> UCL, London\n>>> \n>>> w: +44(0)1483 204 100 ext 2299\n>>> m: +44(0)7938 55 70 44\n>>> \n>> \n> \n> -- \n> ---\n> Roger J A Duthie\n> PhD Candidate\n> Plasma Group\n> Department of Space & Climate Physics\n> UCL, London\n> \n> w: +44(0)1483 204 100 ext 2299\n> m: +44(0)7938 55 70 44\n\n", "attachments": [] }