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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/EGW7O2EH4D7M3ZMVN6YGPUKIMHWF334D/?format=api",
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    "message_id": "000801cbb681$4fae71e0$ef0b55a0$@com",
    "message_id_hash": "EGW7O2EH4D7M3ZMVN6YGPUKIMHWF334D",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/Z5F5732S6SSHN2M5LNKXMWBNXNUKWKTH/?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: Funcube dongle results Jan 16th",
    "date": "2011-01-17T20:01:10Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/Z5F5732S6SSHN2M5LNKXMWBNXNUKWKTH/?format=api",
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hi Henk\n\nParticularly regarding your attempt to receive the ISS, do you see a\nsignificant increase in noise floor when you connect the antenna at VHF,\npotentially 20dB or more?\n\nIf so, it may be being overloaded from the sum of VHF signals coming into\nthe radio. When you use a preamp it almost certainly has a bandpass filter\nin it. The filtering on the FCD at VHF is rather wide bandpass with 3dB\ncutoffs between about 60MHz and 270MHz. Thus if there's significant pager,\nband II FM, or Band III DAB etc traffic the front end gets a bit swamped,\nand your noise floor rises.\n\nWe're already looking into simple recommended methods of alleviating this.\nThe first thing is to make sure you're using the 18c firmware as this\nimplements tighter filtering. I also found that simply using the VHF port of\na V/U di/duplexer worked well in some situations. The best results I found\nwere with the middle port of a CFX-514 triplexer. If you have close in pager\ninterference then you'll need something rather tighter. In the UK for\nexample, we often have pagers at 138 and 153MHz.\n\nAt UHF and above, the FCD uses tighter programmable bandpass filters so we\ndon't tend to experience this at these frequencies.\n\nThe front end of the FCD is pretty sensitive, with all units measured and\ntargeted for 0.15uV for 12dB SINAD on NBFM. But if there are fairly strong\nout of band signals, this will inevitably raise the noise floor.\n\n73, Howard G6LVB\n\n-----Original Message-----\nFrom: [email protected] [mailto:[email protected]] On\nBehalf Of PA3GUO\nSent: 16 January 2011 21:10\nTo: [email protected]\nSubject: [amsat-bb] Funcube dongle results Jan 16th\n\nSome more FUNCube dongle results:\n\n(not much new information, just want to share my few hours\ntime today to spend on the FCD which I really enjoyed)\n\nUsing 2x6 elements 145 MHz:\n- VO52 USB downlink great, with and without preamp\n\nUsing 1x12 elements 435 MHz\n- AO51 FM downlink great with preamp, without noisier\n- HO68 CW beacon great with preamp, good without\n\nOK. So with the normal antennas the FCD works great.\nTime to try thew absolute minumum: Outside in the garden, laptop\nplus a simple vertical for 145 MHz; ISS packet: nothing heared/seen.\nWas a surprise to me, as ISS is normally extremely strong.\nAlso tried AO51 FM with just a dipole outside: nothing heared/seen.\nBoth passes were >80 degrees elevation.\nSo for now I guess you need either a beam or a preamp.\n\nThen again, the unit is the size of a USB memory stick and\nhas a range 60MHz -1.7 GHz - no complaints !\n\nOveral I am still very impressed. The dongle connected to my\nnormal antenna system (beams + pre-amps) gives great results.\n\nJust listened twice to a VO52 pass, and listening in USB was very\ncomfortable, audio sounds very nice until 0 degrees elevation\n(using WRplus).\n\nAmazing to be able to watch the entire downlink spectrum, and\nsee a few QSOs in parallel, seeing multiple stations tuning (their\nsignals going from left ro right and back until they hear themselves).\n\nOf course everyone else had SDR for satellites already :-) For me\nthis is just amazing. Great work by the FUNCube Dongle team.\n\nWe often see discussions on how to get SSB for a few $'s and start\nto compare various conventional transceivers. Well, the FCD is surely\nan option to reduce cost on the downlink: all mode / all bands.\n\nHenk, PA3GUO\nhttp://www.youtube.com/watch?v=xFZGlqKPPQo\n\n\n\n_______________________________________________\nSent via [email protected]. Opinions expressed are those of the author.\nNot an AMSAT-NA member? Join now to support the amateur satellite program!\nSubscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n\n",
    "attachments": []
}