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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/X333JDOBDZKINPACRNO7TUS2G6UCQ6DO/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "X333JDOBDZKINPACRNO7TUS2G6UCQ6DO",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/X333JDOBDZKINPACRNO7TUS2G6UCQ6DO/",
    "sender": {
        "address": "daniel (a) destevez.net",
        "mailman_id": "c2eac82b839b45f5a7d3b923c1721007",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/c2eac82b839b45f5a7d3b923c1721007/emails/"
    },
    "sender_name": "Daniel Estévez",
    "subject": "[amsat-bb] First impressions on FO-29",
    "date": "2015-02-05T14:24:23Z",
    "parent": null,
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/YGGCJXZE3X2TWTPFEWWLA43MO2G4CB6J/"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi everybody,\n\nI'm setting up a portable satellite station to work the linear and FM\nbirds. The equipment is a Funcube Dongle Pro+ for RX (with a diplexer to\navoid desensing), an FT-817ND for TX and a homebrew handheld yagi\nsimilar to the arrow satellite antenna (3el on 2m and 6el on 70cm, DL6WU\nspacing). I use computer control for Doppler on both RX and TX.\n\nI'm quite a newbie to the satellite world and yesterday it was the first\ntime I managed to hear myself on the downlink of some satellite, after a\nfew unsuccessful attempts (in which I also had to cope with bad\nweather). It was on FO-29, at about 17:00UTC, 4th February (my locator\nis IN80do). I'm quite excited about it. Hopefully, next time I will be\nable to work some contacts.\n\nI have some impressions and some questions on operating tips that may be\nuseful. The first impression is that it's very nice to use an SDR with\nDoppler correction for RX, because I get to see the full passband of the\ntransponder and the beacon of the sat, and the frequencies I see at my\nscreen are the frequencies as transmitted by the satellite. I can see\nthe Doppler of the satellite by looking at how local spurs sweep up\nacross the band, and I can also check the precision of my TLE's by\nchecking if the beacon drifts. This time it was rock solid.\n\nIt also seems that most people tune only their receive, since the QSOs\nslowly get higher in frequency. This is probably the most sensible thing\nto do if you're not using computer Doppler control, because FO-29 is\nV/U. I've also seen that most people crowd the centre of the passband,\nat about 435.850MHz. FO-29's transponder is 100KHz wide but I've heard\nthat the downlink is stronger near the centre of the passband. Does\nanyone know how much the difference is or if this hardly matters at all?\nAlso, since I'm using full Doppler control, is there any suggestion for\na frequency on which to call CQ? If I'm just next to a station which is\ntuning only the downlink, I will be run over when he goes up due to\nDoppler shift, so I have the impression that I'll be probably better at\nsomething like 435.840MHz, with most people above me. Or is this lower\npart of the passband for CW? Of course this question is only for FO-29.\nIt doesn't apply to AO-73 because its passband is only 20KHz, so there\nis not much free room usually.\n\nAnother nice thing of the SDR is that I have it calibrated to report\nsignal strength in S-units (with S9 = -93dBm) in a more or less accurate\nway. This way, I can see that my noise floor is S2, the beacon ranges\nbetween S3 and S4, and strong stations are S5 to S6 in the downlink.\nWould you guys consider it useful if I use this \"true\" measurements when\ngiving signal reports? I hear that most people go with 59 or 58 or\nnothing at all, but keep in mind that with my setup a report of 56\nreally means 12dB above the beacon, and nobody will likely be 59 if\nthat's at all possible, keeping in mind the power of the satellite and\nthe path loss equation.\n\nMy own downlink had about the same signal strength as the beacon. I\nguess that's about right to make plenty of contacts. I also read\nsomewhere that you should adjust your power to be about the same\nstrength as the beacon. I keep hearing stations much stronger than the\nbeacon, so I guess that it's not practical for everybody to measure\ntheir downlink strength or lower their power.\n\nI also heard people working some stations that for me where completely\nin the noise for me, so I guess these people have much better RX\nequipment than me. Those of you with good RX, could you provide an\naccurate measurement of strength of the beacon for you so I can compare\nwith my own measurements?\n\nAnother thing that I observed is that there were FM signals on two\nfrequencies being repeated by the transponder. This had the Doppler\nshift that a fixed frequency 2m signal will have when repeated by the\nsatellite. One of the signals had CTCSS while the other didn't. The\nsignals where two weak to copy, but it seemed that the language was\nSpanish. It seems that it people talking on FM simplex about 145.985MHz.\nDoes this happen often? It's a pity that people don't follow good\noperating practices.\n\nFinally, sorry for the long post, and in case anyone wants it, I have a\nfull SDR recording of the pass. I will usually be recording the SDR when\nI'm working satellites, so if anyone finds these useful, please let me know.\n\nHope to work you soon on the satellites.\n\n73,\n\nDani EA4GPZ.\n\n\n",
    "attachments": []
}