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GET /hyperkitty/api/list/[email protected]/email/QFJGMUPWBEWV25AWFBXV5DJ6OEKGMWHK/?format=api
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/QFJGMUPWBEWV25AWFBXV5DJ6OEKGMWHK/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "E85C1D345772454E8596FE496F36A99A@WA4SCA", "message_id_hash": "QFJGMUPWBEWV25AWFBXV5DJ6OEKGMWHK", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/EKUDXYKHK5GFZBJBDILTUCJRDYFTDOTJ/?format=api", "sender": { "address": "APBIDDLE (a) UNITED.NET", "mailman_id": null, "emails": null }, "sender_name": "Alan P. Biddle", "subject": "[amsat-bb] Re: probably simple", "date": "2010-01-08T14:15:05Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/EKUDXYKHK5GFZBJBDILTUCJRDYFTDOTJ/?format=api", "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Bob,\n\nYears ago, Paul Williamson wrote a brief note on the tuning issue. It was\nprescient in the days of primitive computers, few rigs with easy remote\nfrequency control, and very limited choices of tracking software. Take a\nlook at KB5MU's One True Rule paper:\n\nhttp://www.amsat.org/amsat/features/one_true_rule.html\n\nIf both operators are following it, and SATPC32 (and MacDoppler) does so\nperfectly, to a large extent it effectively sweeps the Doppler issue \"under\nthe rug.\" You can tune around, and always hear yourself when you key the\nrig and say \"aaaaah.\" More importantly, if the other station, say 5Y4GB is\nusing the similar technique, when you tune him in, he will hear you on\nfrequency. If WA4SCA then joins the QSO, both of you will hear me on\nfrequency, and I will hear both of you the same. Even more importantly,\neverybody will remain in sync over the pass. It happens all the time on\nAO-7, HO-68 in linear mode, etc.\n\nAs to your question about 145.950 MHz. If he tunes his RIG to that\nfrequency, and you tune your RIG, you will NOT be on the same frequency\ninitially. However, you will be close. +/- Doppler. This is equivalent to\nan HF station saying he will be tuning 14.210 MHz +/- 5 KHz. It requires a\nbit of initial tuning, but it is quick, and completely removes the worry\nabout tuning the uplink radio. The software automagically does it for you.\nOnce you tune him in, just talk. It is well worth the effort to absorb the\ntechnique, and as more stations use it, the easier it will be to talk\nwithout slowly drifting on top of others. Once you get above the V and U\nmodes, the Doppler shift is so large, and changes so rapidly, that it is\ntruly almost necesary.\n\nWith a slight modification to the exiting software, and a paradigm shift in\nhow we think about what frequency we are on, it is possible to specify the\n\"contact frequency\" for everybody to use which will eliminate the initial\nhunting. But that is for another rant. ;)\n\nAlan\nWA4SCA\n\n\n\n \n\n-----Original Message-----\nFrom: [email protected] [mailto:[email protected]] On\nBehalf Of Bob- W7LRD\nSent: 07 January, 2010 23:59\nTo: Andrew Glasbrenner\nCc: [email protected]\nSubject: [amsat-bb] Re: probably simple\n\n\n\nHi Greg, Drew, etc \n\nThis conversation is starting to make my head hurt! My example is to\nconnect with some of our European friends. Some of them I share maybe a 60\nsecond window, with PA1TNO it is less than 30 seconds. I have had several\nfalse starts in that I heard Paul 2E1EUB, by the time I located my downlink\non his, he was gone. I want to predetermine where to set my uplink for a\ngiven downlink. There just is no the time be looking around. Like I said\nthis is probably simple I'm just have trouble getting my thinking around the\nconcept. Also if say I am planning on a downlink of 145.950 will Paul be\nlooking at the same frequency? In the past these concepts never concerned\nme as there was always plenty of time to yak it up with the locals on AO-7. \n\n73 Bob W7LRD \n\nCN87 Seattle, Wa. \n\n\n\n\n\n\n\n\n----- Original Message ----- \nFrom: \"Andrew Glasbrenner\" <[email protected]> \nTo: \"Greg D.\" <[email protected]> \nCc: [email protected], [email protected] \nSent: Thursday, January 7, 2010 9:30:44 PM GMT -08:00 US/Canada Pacific \nSubject: Re: [amsat-bb] Re: probably simple \n\n\n> \n> \n> But any pass where you are really stretching the footprint is going to \n> be a low elevation pass. The more you stretch, the lower the pass. \n> In the limit, I think Bob's ultimate pass has a peak at .001-degrees \n> for both stations. If you're doing that, then you're at TCA, and zero \n> doppler. \n> \n> That's all I meant to convey, \n> \n> Greg KO6TH \nI understand, but with all due respect your assumption is incorrect that \nlong distance QSOs are always at TCA and zero Doppler, even \ntheoretically . This is only the case when the two stations are at near \nright angles to the track of the satellite. \n\nUse the following example. If I want to work LU5BOJ/O in FG75 from EL88 \non HO-68, my only windows are at either LOS or AOS, depending on whether \nit is an ascending or descending pass. Neither pass will be a low pass \nfor either station, and neither QSO will occur at TCA or zero Doppler. \n\nIn Bob's case, let's look at his next possible window with Paul, 2E1EUB \nin IO92. Bob is in CN76. At the beginning of the 1 minute window \ntomorrow at 1251Z, Bob's Doppler shift on 432 is -3.68 khz. \n\nOn the next mutual window at 1452Z, the beginning Doppler is -7.93 khz. \nOn the next, at 2020Z, it's -8.3 khz. None of these windows are over 2 \ndegrees elevation, and none are at TCA for either station. \n\nWhen you have 60s to make the QSO, being right dead on frequency is \nessential. \n\nRespectfully, \nDrew KO4MA \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", "attachments": [] }