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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/6CSOT4OIXUKUBGRHUOKQGWC2IT7B6YFU/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "CAHKCqnATgxi=DgdDJjCdCtjUK1PAULAtvXWkvsWJjt+ng59h6A@mail.gmail.com",
    "message_id_hash": "6CSOT4OIXUKUBGRHUOKQGWC2IT7B6YFU",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/7S7ONZTXUYAQH5IHZHL5RX57AAYXV3GJ/?format=api",
    "sender": {
        "address": "mjohns+K0JM (a) luther.edu",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Mark D. Johns",
    "subject": "Re: [amsat-bb] Tuning M2 LEO pack antennas",
    "date": "2020-04-20T19:02:47Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/7S7ONZTXUYAQH5IHZHL5RX57AAYXV3GJ/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/XWF7W7BCTX3SURU7UBDDQNRWG257DUPA/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Carl,\n\nI just went through this with my LEO-Pack that has been up for almost\n8 years. I didn't have good test equipment available when I first put\nit together. When I started having trouble recently, and tested it\nproperly, I discovered SWRs on 2m very much as you describe. On advice\nfrom people on this list, I went back to the assembly instructions and\ndiscovered that I had actually not put the antenna together properly\nto begin with. The diagram(s) in the instructions are somewhat\nconfusing, and I would say, even a little misleading. Look at the\nPHOTOGRAPH in the instructions very, very, VERY closely and make sure\nthat the various blocks and phasing lines are placed exactly as shown\nin the photo. It's difficult to see, but if you study it closely and\nduplicate what's in the photo I think you'll find you have better\nresults. I did. Now 1.1:1 at 145.9 MHz.\n\nYou probably want to be using LMR-400 UltraFlex around the rotators.\nRegular LMR-400 is awfully stiff. Bring it along the antenna boom\nstraight back, then keep going straight back, along the same axis, for\nabout a foot past the mounting clamp. Then make a nice wide loop back\nto cross boom to which the antenna is mounted and fasten the coax\nthere at a point near the end of the reflector. Don't make a sharp\nbend or kink in the coax. Good luck. 73\n--\nMark D. Johns, KØJM\nAMSAT Ambassador & News Service Editor\nBrooklyn Park, MN USA   EN35hd\n-----------------------------------------------\n\"Heaven goes by favor; if it went by merit,\n   you would stay out and your dog would go in.\"\n    ---Mark Twain\n\nOn Mon, Apr 20, 2020 at 12:15 PM Carl A Estey via AMSAT-BB\n<[email protected]> wrote:\n>\n> Recently I bought through AMSAT the LEO pack and assembled and installed it this weekend. The SWR on the 2-meter antenna is 1.4:1 from 144.1 to 146.1 with resistance of 58 ohms and 2.5:1 at 148 MHz.  The 70-cm antenna has the best SWR (3.0:1 and resistance of 25 ohms) at 442.6 MHZ.   Obviously neither is great.\n>\n> How should I tune the antennas?  It appears that the only tuning possible is to adjust the shorting straps for distance from the inside edge of the shorting bar to there boom.  ShouldI I be able to achieve 1.1:1 on both antennas?  How should the coax be routed from the junction block?  I have the LMR-400 feedline zip tied along the boom to the cross bar and then around the rotors.\n>\n> What suggestions do you have?\n>\n> The instructions particularly concerning the location of the 1/4-wave phasing line and the 1/2 wave balun were not very clear.  Does anyone  have any pictures or illustrations that show placement of the tasing line and balun?\n>\n> 73\n> Carl WA0CQG\n>\n> _______________________________________________\n> Sent via [email protected]. AMSAT-NA makes this open forum available\n> to all interested persons worldwide without requiring membership. Opinions expressed\n> are solely those of the author, and do not reflect the official views of AMSAT-NA.\n> Not an AMSAT-NA member? Join now to support the amateur satellite program!\n> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb\n",
    "attachments": []
}