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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/IGAO3PM5MNRWJJSU2276GFSJFASPXFNQ/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "IGAO3PM5MNRWJJSU2276GFSJFASPXFNQ",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/TVECUMZOV55OF66ZQHVYLWGDTBMCJWM7/",
    "sender": {
        "address": "nate (a) natetech.com",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Nate Duehr",
    "subject": "[amsat-bb] Re: SINAD Vs. Noise Figure Testing",
    "date": "2008-12-10T00:01:23Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/XMIS3GF457GT5O3XBMFZGLMGQZYDG4IE/",
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Michael Heim wrote:\n> Stan makes a good point here, especially for FM sensitivity.  I\n> worked in the 2-way business for a long time, and typically a sinad\n> measurement would be something like the value of microvolts at the\n> antenna input for 20 dB of quieting of the receiver.  It is basically\n> a measurement of FM receiver sensitivity.  It will also show\n> mis-aligned IF strips and detector, but for the sake of arguement in\n> this case, lets say the receiver is functioning normally.  The goal\n> should be the minimum amount of signal input at the antenna connector\n> quiets the receiver 20 dB.\n\n<http://www.repeater-builder.com/tech-info/20dbquieting.html>\n\nOften times folks building repeaters and/or doing other weak-signal\n(contesting) work at VHF and above have great documentation and\ninformation that applies just as much to satellite operation.\n\nIt's always worth \"popping our heads up\" from our own little RF worlds\nand looking around a bit once in a while.  (Like Prairie Dogs.)\n\nI agree with you, a SINAD measurement on an SSB receiver is kinda not \nthe right idea.  It'll show you something, but what... I'm not quite \nsure.  It CAN be used for a comparison measurement for changes, though.\n\nThus, the best thing about learning how to make a SINAD measurement, \nmeasuring or at least calculating Noise Figure, or WHATEVER measurements \nis this:\n\nYou can make CHANGES and see if you made things better or worse.\n\nWhy is that important?\n\nIt changes your hobby from subjective (\"that sounds better\") to \nquantitative (\"I made my home VHF setup 3dB more sensitive on VHF \ntoday\"), which is a sign you're trying harder than the majority to have \na great receiver setup and antenna system.\n\nAnother useful measurement is to find the receiver's sensitivity while \ninjecting the test signal while connected to an outside antenna, after \ndoing it without... to see how local noise/intermod/etc., affects your \nreceiver.\n\nA home-made \"Iso-Tee\" set up for a known amount of loss on your test \nsetup, or a directional coupler with a known amount of loss are needed \nfor that test.\n\nNate WY0X\n",
    "attachments": []
}