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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ODJJGIW63D6G3L5XQUUD6HBJ6RTLOJBI/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "050820070413.14406.463FF8F7000C64BB0000384622165514060B9D04C999@comcast.net",
    "message_id_hash": "ODJJGIW63D6G3L5XQUUD6HBJ6RTLOJBI",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/ODJJGIW63D6G3L5XQUUD6HBJ6RTLOJBI/?format=api",
    "sender": {
        "address": "w7lrd (a) comcast.net",
        "mailman_id": "717aa2a241704c7497e9abd8c983f6b7",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/717aa2a241704c7497e9abd8c983f6b7/emails/?format=api"
    },
    "sender_name": "[email protected]",
    "subject": "[amsat-bb] Re: Helix vs. loopers",
    "date": "2007-05-08T04:13:43Z",
    "parent": null,
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/FFBJA2RJLBVLUTLLKVDYUCV7QKLUO4FU/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Steve and all\nI believe simply lengthing a helix will reach a point of diminishing returns.  It would be better to stack a couple or even four twenty or so turn turn helix antennas (from VE3NPC).  You could  with proper phasing generate a CP signal from a couple of loopers.  I just haven't heard of anyone doing that, though it looks good on paper.\n73 Bob W7LRD\nSeattle\n\n-------------- Original message -------------- \nFrom: Steve Raas <[email protected]> \n\n> In reading much of the discussion that has hit the BB lately in regards to \n> antennas I figured Ide toss in my questions to the group. \n> \n> \n> \n> In trying to figure out which style antenna is going to suit my needs best I \n> have a few questions. \n> \n> \n> \n> #1 Is a linear polarized antenna less efficient than a RHCP antenna when \n> trying to receive or transmit to a rhcp signal / receiver? \n> \n> \n> \n> #2 If yes.. in theory how much? \n> \n> \n> \n> #3 In looking @ pre-built helix options for 1.2g I have found the DSH23-12 \n> which is a 23 cm RHCP 12 turn helix 14.5 dBic gain in a machined radome for \n> best weather protection. 1.2-1.3 GHz bandwidth. 50 ohm feed wit h N (f) \n> connector on 8\" backplane. All stainless hardware; Designed for PHASE 3D \n> uplink operation. Wide bandwidth actually covers from 900 - 1600 MHz ( \n> copied verbatium from the www.directivesystems.com website. In looking at \n> the specs of this helix, it seems it may not have the desired gain for P3E \n> or others. In 'theroy' is it possible to make a 24 turn helix , and if so \n> would I be correct in thinking that double the turns would provide at or \n> near 3.0 db of additional gain? \n> \n> \n> \n> #4 If yes to question 3 would this antenna be @ or near double the physical \n> length? \n> \n> \n> \n> \n> \n> In a email I sent to Dave @ Directive he told me that the loopers he has can \n> be arranged for vert/linear or horizontal polarization, so I do think that a \n> looper although a great antenna may not be the best single antenna solution \n> for 1.2 Uplin k. \n> \n> \n> \n> Thoughts, Ideas & comments please. \n> \n> \n> \n> \n> \n> -Steve Raas \n> \n> N2JDQ \n> \n> FN20vg \n> \n> _______________________________________________ \n> Sent via [email protected]. Opinions expressed are those of the author. \n> Not an AMSAT-NA member? Join now to support the amateur satellite program! \n> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb \n",
    "attachments": []
}