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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/GELNKDFSPL5QACPZ3BF644QCFZGKUMDT/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "GELNKDFSPL5QACPZ3BF644QCFZGKUMDT",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/GQN66W4DHOQJYEXDIZCCLWG3525EQ6AV/",
    "sender": {
        "address": "K3IO (a) verizon.net",
        "mailman_id": "79a9b3ddaa4b44baae47f92374974ac4",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/79a9b3ddaa4b44baae47f92374974ac4/emails/"
    },
    "sender_name": "Tom Clark, K3IO",
    "subject": "[eagle] Re: Where we're heading for bands and services",
    "date": "2006-09-25T05:41:57Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/SCKNWTPEXSFESMY4IBFJRIQWWYY7TG3I/",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/GKGXY26HPDEHPBI2PFOOI57P72VGCHLJ/"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Lyle Johnson wrote:\n> I discussed some of these ideas with Eric, N7CL, at the TAPR meeting. \n> Eric is very good at antenna system design, did S band stuff for us at \n> MMS and does this sort of thing now for DoD.\n>\n> Anyway, he suggested we consider Vivaldi's rather than patches.  We used \n> Vivaldi's on our trucks at S Band and they work well, are trivial to \n> fabricate (a piece of PC board - I know, radiation, but it is the \n> concept I am wanting us to consider).  They are well behaved and have \n> very little coupling to adjacent antennas.  I'm not an antenna guy, but \n> you might want to consider the Vivaldi and/or communicate with Eric.\n>\n>   \nEric also assisted me with the design of the Microsat 2M rcvrs -- which\nbore a strange similarity to an MMS design.\n\nAFAIK, the Vivaldi and antipodal antennas are linearly polarized.\nMultiple elements require crossed antennas, like Fig.9 in\nhttp://www.ansoft.com/news/articles/04.09a_MWJ.pdf#search=%22vivaldi%20antenna%22\n(note that the radiation is \"endfire\").\n\nA PhD thesis for a 2-8 GHz describing this antenna used for a Snow radar\nis seen at\nhttp://profusion.ittc.ku.edu/research/thesis/documents/ravi_prakash_rajaraman_thesis.pdf#search=%22vivaldi%20antenna%22.\nAlso, to see what an array of these devices might look like, see\nhttp://nemes.colorado.edu/microwave/papers/2000/APS_JPWbn_00.pdf#search=%22vivaldi%20antenna%22\n(in this case, the SKA is a concept design for an SKA=square-kilometer\narray for radio astronomy. Many different approaches are being studied\nranging from a field full of tens of thousands of patch antennas, each\nequipped with signal processing \"smarts\" to arrays of a hundreds of\ndishes. See http://www.skatelescope.org/ for more info)\n\n73, Tom\n\n",
    "attachments": []
}