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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/LNTUCMQ5VLO6A3MTPAME7DF36332GDTF/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "[email protected]",
    "message_id_hash": "LNTUCMQ5VLO6A3MTPAME7DF36332GDTF",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/FPQ3IOK7YULKQEKW67HZNRPRRJI64S2V/?format=api",
    "sender": {
        "address": "8p6sm (a) anjo.com",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Gus",
    "subject": "[amsat-bb] Re: inquiry about homebrew az-el systems",
    "date": "2013-02-24T02:25:48Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/FPQ3IOK7YULKQEKW67HZNRPRRJI64S2V/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/UZQUWYOGQZVZYV76CEGJ4GYOQ3J2LT7R/?format=api",
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/BWEY7FI6ZZODV5KHTQKTFUOSEGJULRPO/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
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    "content": "Given the shortage of LEO birds, exactly how much antenna do we need to \nrotate?\n\nHams operate satellite successfully with hand-held antennas, which have \nlow wind-loading and are light in weight.\n\nWith R/C servos available producing 6½ ft. lb of torque for less than \n150 bucks, I'm surprised a light weight, portable, DC-operated satellite \nsystem complete with antennas and AZ/EL rotors  hasn't materialized \nbefore now.\n\nOn 02/23/2013 07:59 PM, Samudra Haque wrote:\n> Hi, about two years ago, I started a design for a robotics class project of\n> a AZ-EL rotator controller system, and a hardware package for the mechanism\n> for rotating an antenna in any direction subject to mechanical stops. The\n> system would have been able to handle regular and flip modes. I didn't do\n> anything more than calculations, and moved on to building a classroom\n> instructional robot then.\n>\n> Lately, as I am setting up (K3GWU, the George Washington University Amateur\n> Radio Club and Research Station) I find that the price of az-el systems\n> such as G5500 + Yaesu AZ-EL rotors are expensive, and are not typically\n> available on an affordable basis on Ebay or eham.net etc. Well, of course,\n> expensive is a relative term, for a student hobby organization, it's a lot,\n> and I guess for small ham operators it is also moderately expensive.\n>\n> This may be a frequently asked topic: does any one have experienced with\n> (tested) kit designs for AZ-EL rotors that can be made with parts from\n>   current suppliers ? I know there are a number of controller designs, but I\n> am interested to know if there are any options for suppliers of the\n> required gears/motors etc.\n>\n> I have located several large AC motors / DC motors at my university\n> mechanical engineering workshop, but they are not all guaranteed the same\n> specs. I now realize if I do embark on a actual design process with my\n> model/simulation/hardware, it would be nice to build several of these all\n> at once to share the development cost over the production run, and ensure\n> those who want a cheap AZ-EL system can get one. Otherwise the production\n> cost of one heavy duty system is going to be quite high.\n>\n> I hope some of you may have suggestions for me, both (+) and (-) or perhaps\n> (~) in nature. I thought amsat / amateur radio folks have a common need to\n> encourage homebrew activity to keep their brain cells in working condition?\n>\n> I'm opening this question up to the national US audience, and welcome any\n> discussion on the challenges of making the ever-so-important\n> azimuth-elevation rotor. I've studied some of the alternatives: Alliance\n> U100 and Yaesu G-5500. I think we can do better in 2013. But ideally, to\n> allow the wide adoption of AMSAT ground stations, what price point would\n> the system have to be to make it worth building ?\n>\n> 73 de N3RDX\n> George Washington University\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-- \n73, de Gus 8P6SM\nBarbados, the easternmost isle.\n\n",
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}