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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/FFBJA2RJLBVLUTLLKVDYUCV7QKLUO4FU/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "000a01c7912b$dac763b0$0200a8c0@kc6uqh",
    "message_id_hash": "FFBJA2RJLBVLUTLLKVDYUCV7QKLUO4FU",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/ODJJGIW63D6G3L5XQUUD6HBJ6RTLOJBI/?format=api",
    "sender": {
        "address": "kc6uqh (a) cox.net",
        "mailman_id": "d9201820d18047e4a2772c86bda5e111",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/d9201820d18047e4a2772c86bda5e111/emails/?format=api"
    },
    "sender_name": "kc6uqh",
    "subject": "[amsat-bb] Re: Helix vs. loopers",
    "date": "2007-05-08T04:46:34Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/ODJJGIW63D6G3L5XQUUD6HBJ6RTLOJBI/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/B3IBPE6BN7ZIEXI4T72ZIGWM2NLQVE74/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "You loose 3 dB linear to circular, circular to circular of the same rotation \nis best for satellite work eliminating fading during rotational shift and \nmultipath.\nI agree about diminishing returns on a Helix. I have phased two for linear \npolorization ( counter rotating 1.2 GHz). The BBQ grill is a simple \nsolution, 18 dBi 1.2 and 24 dBi 2.4 with a small form factor, I use it \nportable and it fits in my car. If you have room for a 12' boom why not a \n10' TVRO dish? You could go portable with a Semi Truck!\n\nArt\n----- Original Message ----- \nFrom: <[email protected]>\nTo: \"Steve Raas\" <[email protected]>; <[email protected]>\nSent: Monday, May 07, 2007 9:13 PM\nSubject: [amsat-bb] Re: Helix vs. loopers\n\n\n> Steve and all\n> I believe simply lengthing a helix will reach a point of diminishing \n> returns.  It would be better to stack a couple or even four twenty or so \n> turn turn helix antennas (from VE3NPC).  You could  with proper phasing \n> generate a CP signal from a couple of loopers.  I just haven't heard of \n> anyone doing that, though it looks good on paper.\n> 73 Bob W7LRD\n> Seattle\n>\n> -------------- Original message -------------- \n> From: Steve Raas <[email protected]>\n>\n>> In reading much of the discussion that has hit the BB lately in regards \n>> 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 \n>> 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 \n>> DSH23-12\n>> which is a 23 cm RHCP 12 turn helix 14.5 dBic gain in a machined radome \n>> 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 \n>> 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 \n>> 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 \n>> can\n>> be arranged for vert/linear or horizontal polarization, so I do think \n>> that a\n>> looper although a great antenna may not be the best single antenna \n>> 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 \n>> program!\n>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb\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> \n\n\n",
    "attachments": []
}