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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/4RTMGQDKAFG7KPVBZ6LLC6IPFIJE3KPX/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "4RTMGQDKAFG7KPVBZ6LLC6IPFIJE3KPX",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/ZCE7G63BF7UEF24X2Z7AON7E267AUBCF/",
    "sender": {
        "address": "hartzell (a) gmail.com",
        "mailman_id": "11e371d6dacd43b7a2b3a3c751e6641e",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/11e371d6dacd43b7a2b3a3c751e6641e/emails/"
    },
    "sender_name": "Dave hartzell",
    "subject": "[amsat-bb] Re: Redundant geostaionary birds?",
    "date": "2007-01-29T00:41:41Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ZCE7G63BF7UEF24X2Z7AON7E267AUBCF/",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/OBQJQBE4SZZP27IWZDFXO5LX4K4XT2KT/"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi Andy,\n\nI have often wondered the same, whether amateurs could use\nout-of-service geostationary birds, but the reality is:\n\n1) Most end-of-life geo-stat birds should get moved into a \"disposal\norbit\" well above 22,240 miles.  The geo-stat parking spots are\nprecious and must be reused.\n\n2) If for some reason a bird could not get into parking orbit, its\nprobably dead (e.g. no power, comms, etc).  Drifting will begin, and\nthe spacecraft will probably move into a geo-sync orbit (figure eight\naround its initial geo-stat orbit) and slowly toward the equilibrium\npoints.  For this reason every effort is made to move the spacecraft\ninto the super-sync disposal orbit.\n\n3) Most of the uplink freq's are in the 5.9 GHz range (out of our\nallocation) and downlink in the 3.7 GHz range, again, (out of our\nallocation).\n\nThere was a plan for a C-band to C-band transponder on Eagle, but that\nhas been dropped.\n\nI heard that several years ago there was talk of putting an amateur\ntransponder onboard a commercial geo-sync bird.  But I suspect\neconomics and the fact that all extra mass is reserved for\nstationkeeping fuel.  Plus power is always critical, and over time,\nthe solar panels generate less.  Anyone know more about this?\n\n73,\n\nDave\nNøTGD\n\n\nOn 1/28/07, Andythomas <[email protected]> wrote:\n> Hi gang,\n>\n> I was reading an ESA press release about satellite radio experiments and\n> didn't realise its emphasis on re-using redundant broadcast tv satellites\n> until I read the bbc version of the story at:\n>\n> http://news.bbc.co.uk/1/hi/technology/6301359.stm\n>\n> which explains that when the broadcast geostationary saetllites lose fuel\n> for position control the tv guys lose interest in them, even though the\n> transponders work fine.\n>\n> Then I fell to wondering:\n>\n>  whether we in the amateur satellite service could not use both the up and\n> down links on these redundant geostationary birds?\n>\n> I don't know the exaxct frequencies but there may be one out there that has\n> frequencies we share (or at least the uplink). After all we have years of\n> experience of chasing staellites which are not exactly where they should be\n> in the sky and so the \"wandering geostationary\" satellite shouldn't be a\n> worry.\n>\n> I think each transponder channel is 27 MHz wide??\n>\n> I remember vaguely that there was a \"pipe\" on one of the birds from the UK\n> to the USA which was used in amateur service about 15 years ago now (but I\n> don' t remember very much else).\n>\n> If we could take over one channel on the transponder then immediately we\n> would start looking at uplink equations, multiplex etc. and what about a\n> mobile aprs service?!\n>\n> 90% of the world will tell you why it can't be done. Who can show how it\n> can be done?\n>\n> 73 de andy G0SFJ\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\"It is far better to grasp the Universe as it really is than to\npersist in delusion, however satisfying and reassuring.\" - Carl Sagan.\n\n",
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}