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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/5SHW5Q7SCTQKRVJGJE3KRQD6D5I7RUNR/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "[email protected]",
    "message_id_hash": "5SHW5Q7SCTQKRVJGJE3KRQD6D5I7RUNR",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/5SHW5Q7SCTQKRVJGJE3KRQD6D5I7RUNR/?format=api",
    "sender": {
        "address": "oz1my (a) privat.dk",
        "mailman_id": "b2f56900318d4d1193159750f39aa3fe",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/b2f56900318d4d1193159750f39aa3fe/emails/?format=api"
    },
    "sender_name": "OZ1MY",
    "subject": "[amsat-bb]  SSB uplink to AO-51 on 2 meters and 1268 MHz",
    "date": "2006-10-28T12:56:32Z",
    "parent": null,
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/TN6FX7NCSA2L5PCAL5MCDZY25QGEUZ2Z/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi all,\n>From Monday AO-51 will be in SSB mode on the uplink like\nit has been before.\n\nOctober 30 to November 6\nCross Mode Repeater, V(SSB)/U(FM)\nUplink: 145.880 MHz USB\nDownlink: 435.300 MHz FM\n\nThose of you who have tried it before know that you must hit\nthe frequency correct to get a good downlink signal.\nIf you use automatic doppler shift correction from your tracking\nprogram it is a little bit easier.\n\nPersonally I use SatPC32 to do the correction with the following\nline in the doppler.sqr file:\n\nAO-51,435300,145879.25,FM,USB,Nor,0,0,Voice V/U\n\nThis worked very good last time we had this mode running\non AO-51. Your transceiver may need small adjustments\nto the uplink frequency.\n\nThe coming week can be used to get the feeling for running\nSSB up to AO-51. The experience gained will be needed\nwhen AO-51 is the new mode with L-band SSB up in\nDecember.\nThat is going to be very interesting since the doppler shift will\nbe very fast with this much higher uplink frequency.\nThe rate of change of frequency will be something\nlike 340 Hz pr. sec. Worst Case.\nOf course it will be less most of the time so that it\nmight be possible to do the tuning by hand.\n\nDecember 8 to December 11 New Mode!\nCross Mode Repeater, L(SSB)/U(FM)\nUplink: 1268.700 MHz USB\nDownlink: 435.300 MHz FM\n\nI ran some tests on HITSAT. It has a Worst Case rate\nof change of approximately 300 Hz. pr. sec. since it\nhas a perigee of 290 km. That is not easy on close passes.\n\nLessons learnt :\n\nMake sure the PC clock is correct within 0.1 s\nMake sure your position is correct (a friend with a GPS receiver helped on\nthat one)\nThe keplerian elements must be correct ( difficult to control)\nThe tracking program MUST use SGP4/SDP4 (I tested with an older program with\nPLAN 13 and that was up to 2 kHz off)\nYour transceiver/PC/tracker combination must be able to update once every\n0.1 s or faster (special version of SatPC32 in my case)\nFrequencies must be correct in the PC or possible to correct on the fly\n\nThen there are frequency drift of the satellite, your transceiver and so on\n\nThis means that you must update the keplerian elements at least once\na day. Unfortunately this is not necessarily a guaranty since the keps\nsometimes\nare \"bad\".\n\nSynchronize the PC clock before each pass.\n\nLessons learnt are about using automatic full doppler tracking. If you\nuse manual frequency correction try it on the low elevation passes first.\n\nThe mode has never been tried before therefor it is very interesting\nto see how it will work.\n\nHope to hear you on AO-51 mode-L(SSB)/U(FM).\n\nThanks to Colin, VK5HI, and Erich, DK1TB, for help with\nthe doppler correction.\n\n73 OZ1MY\nIb\n\n\n",
    "attachments": []
}