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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/FSJCXDHNUFJYB7TQLLH6VYTWCR4E6C4B/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "[email protected]",
    "message_id_hash": "FSJCXDHNUFJYB7TQLLH6VYTWCR4E6C4B",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/CHO2CGWZUSX464DONNGQX4HFSWMKO47N/?format=api",
    "sender": {
        "address": "JamesDuffey (a) comcast.net",
        "mailman_id": "16d2718d7d4a47dca8f564d867aacfe2",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/16d2718d7d4a47dca8f564d867aacfe2/emails/?format=api"
    },
    "sender_name": "James Duffey",
    "subject": "[amsat-bb] Re: Preamps??",
    "date": "2009-04-12T14:24:45Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/CHO2CGWZUSX464DONNGQX4HFSWMKO47N/?format=api",
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Jerry - Preamps at the antenna help. They help a lot if you have a  \nsetup that is limited by receiver performance and/or feedline loss.  \nThey won't help if you are limited by the noise environment. They  \nusually help a lot for satellite operation as there is usually not  \nmuch external noise when the antenna is pointed to empty space rather  \nthan to your neighbor's lamp dimmer.\n\nFor two meters a grounded gate preamplifier based on the U310 is a  \ngood choice:\n\n< http://www.ham-radio.com/n6ca/50MHz/50appnotes/U310.html >\n\nUnfortunately, the TO-52 style U310 has gotten pretty expensive; I  \nthink they are $11 a piece from Mouser! Still this is a tried and true  \ndesign that is stable and easy to build. You might try the more widely  \navailable and cheaper J310, which is the same part in a plastic package.\n\nMOSFETs also make a good preamp. Here are a couple using the BF981:\n\n< http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=9247 >\n\n< http://www.geocities.com/icdx_australia/bf981preamp.html >\n\nThere are lots of other designs out there. The old ARRL handbooks from  \nthe 90s had some nice designs for both dual gate MOSFETs and GaAs  \nFETs. If you use the same feed line and antenna for transmit, you will  \nneed to add relays to switch around the preamp when you transmit.\n\nAdvanced Receiver Research, ARR, is a source of commercial  \npreamplifiers, and there are some models that have built in RF  \nswitching.\n\nThere are other vendors, with higher prices.\n\nA preamp is a good investment to upgrade your station, but it is not a  \ncure all, particularly if you are dominated by terrestrial noise  \nsource. - DUffey\n\n\n\nOn Apr 12, 2009, at 6:22 AM, Jerry Felts wrote:\n\n> I've seen Preamps mentioned several times now so Who? What? Where? I  \n> have\n> not seen them in the AES catalog I got the other day.  Can you build  \n> one?\n> Need info on them!!\n>\n> Jerry - NR5A\n>\n> -- \n> Jerry - NR5A - South Dakota\n> www.freewebs.com/nr5a\n> http://groups.yahoo.com/group/Minimalist_QRP_Transceivers/\n> http://www.cakewalkblogs.com/nr5asminimalradio/index.aspx\n> http://nr5abeaconblog.blogspot.com/\n> _______________________________________________\n> Sent via [email protected]. Opinions expressed are those of the  \n> author.\n> Not an AMSAT-NA member? Join now to support the amateur satellite  \n> program!\n> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\n\n--\nKK6MC\nJames Duffey\nCedar Crest NM\n\n\n\n\n\n",
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}