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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/P7JBZH7IHZKP5ZZCLAVFQWPS3IUDDQVK/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "005a01ca4cbb$6bc3a660$434af320$@com",
    "message_id_hash": "P7JBZH7IHZKP5ZZCLAVFQWPS3IUDDQVK",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/MH5TBPK46SEOSBNTP2LYWFBPAMKQON6E/?format=api",
    "sender": {
        "address": "howard (a) howardlong.com",
        "mailman_id": "82a1d3d58c6f48898b755d208f81930e",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/82a1d3d58c6f48898b755d208f81930e/emails/?format=api"
    },
    "sender_name": "Howard Long",
    "subject": "[amsat-bb] Re: PIC rotator control, and some LVB Tracker history",
    "date": "2009-10-14T10:45:17Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/J3RM7IUQ2K2PIXQQYUGYBHQ7ADDD6NAA/?format=api",
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Folks\n\n> 1 - rotator control in a moving vehicle to keep a small yagi such as an\n> Arrow pointed at the APRS signal.\n>\n> 2 - antenna parking based on data from a home WX station such as those\n> commonly beaconing on APRS systems.\n\nFWIW, I did exactly that many moons ago back in 2003 when AO-40 was still\nwith us, although it was more of a working prototype than something you'd\nwant to let all and sundry peruse over.\n\nhttp://www.g6lvb.com/images/AO40Mobile.jpg\n\nThis was based on a GPS feeding into a PC that corrected the co-ordinates in\nreal time and fed them to an LVB Tracker, hooking up to a pan and tilt\ncamera mount.\n\nSince then, in 2005, the LVB Tracker 2 was developed, and that can act\nautonomously and take in real time GPS parameters for both position and date\nand time correction, although I must stress that this is not a production\nstrength unit. The LVB Tracker 2 was developed at about the same time as the\nSDX back in 2005. When I presented separate papers for the Tracker 2 and the\nSDX at the AMSAT-UK Colloquium, there was a lot of interest in the SDX, but\nalmost none in the Tracker 2, so further development waned I'm afraid. I\nworked with Gould Smith on it again quite a bit at the beginning of 2008\n(see below), but I still don't believe it's really ready for prime time,\nalthough should some kind soul come up and offer to spend time developing it\nfurther I'd be delighted!\n\nIt took a lot of time and effort to get the Tracker 2 to where it is today,\nmore so than the Tracker 1: the Tracker 2 firmware is five times the size of\nthat in the Tracker 1. Back in 2005, there was a real limit on what you\ncould a achieve in a tiny 28 pin device as well as the limitations of\ncompilers at that time.  The Tracker 2 certainly took to the extreme what\nyou could achieve with the limited ROM and particularly RAM available at\nthat time on such a device. It reminded me of the days when you used all\nmanner of means to squeeze that last byte out of your memory map.\n\nThe Tracker 2 has two redeeming features. Firstly, it can operate as a\nhandheld device with an integrated GPS, but since then the iPhone has come\nalong! Secondly, Tracker 2 will work autonomously. The bad news is that if\nyou run a desktop Tracker 2 based on the original Tracker 1 PCB without a\nGPS, with there being no RTC clock, you have to reset the date and time\nmanually each time you switched it on, so that's a bit of a drawback unless\nyou leave it on all the time. Even then, we found that the crystals drift\nthe RTC rather too much for our liking. I think if time permitted,\nredesigning the LVB Tracker 2 hardware with a new PCB from scratch would be\npreferable, supporting a proper battery backed RTC.\n\nFWIW, I am often asked about the choice of compiler for the LVB Tracker.\nSome history: the early choice of the BKND compilers for the LVB Tracker was\nbecause, way back when, they offered floating point arithmetic for a\nreasonable price unlike other competitive offerings, although you're heavily\nrestricted as to the complexity of your code, so you have to manually code\naround those restrictions. Since then, other more heavyweight compilers have\ncome along, in particular Microchip's own offerings for the PIC18 and above.\nRewriting the code for those compilers would be 'interesting'(!) for someone\nwith some time on their hands, and some $$$ to purchase the compiler.\n\nBut, some good news. Thanks to Gould Smith's good work testing my code back\nin early 2008, I do have some significantly updated Tracker 2 code since\n2005, but please bear in mind this is for experimentation purposes, and\ncurrent work commitments preclude me from opening this puppy up for now, but\nplease feel free to do so yourself! See below...\n\n18F2620 programming software:\nhttp://www.g6lvb.com/Articles/LVBTracker2/PicProg2.exe\nHex file: http://www.g6lvb.com/Articles/LVBTracker2/2620test20d.hex\nSources: http://www.g6lvb.com/Articles/LVBTracker2/2620test_2_0d_001.zip\n\nBy the way, while researching the content here, I came across some\ninteresting LVB Tracker development history shots are here (if you're into\nthat kind of thing):\n\nhttp://www.g6lvb.com/images/lvbtracker1.JPG\nhttp://www.g6lvb.com/images/lvbtracker2.JPG\nhttp://www.g6lvb.com/images/lvbtracker3.JPG\nhttp://www.g6lvb.com/images/lvbtracker4.JPG\nhttp://www.g6lvb.com/images/lvbtracker5.JPG\nhttp://www.g6lvb.com/images/lvbtracker6.JPG\nhttp://www.g6lvb.com/images/lvbtracker7.JPG\n\nJudging by the number of PCBs that have been made, I believe that there are\nnow in excess of 1,000 LVB Trackers out there, although how many are\noperational and how many are sitting in pieces waiting for a rainy day I\ndon't know!\n\n73, Howard G6LVB\n\n\n",
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