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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/FELU6CWNTZGJCXNMSJKXLS5HBO2OSCJY/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "FELU6CWNTZGJCXNMSJKXLS5HBO2OSCJY",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/FELU6CWNTZGJCXNMSJKXLS5HBO2OSCJY/",
    "sender": {
        "address": "k0vty (a) juno.com",
        "mailman_id": "69d7c9bb693a4435bee46454dd0afb25",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/69d7c9bb693a4435bee46454dd0afb25/emails/"
    },
    "sender_name": "Joe v Murray",
    "subject": "[amsat-bb] Re: [Mw] Fwd: Power splitters circular polarization?",
    "date": "2010-06-11T16:17:12Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "My apologies gents\n\nThe attached was the second reply to Gary (WE9Y) that was not sent to the\nBB\nAs you can see after reading the attached a few pictures would have been\na must to really get into\na axis discussion about my original query.\nI took a chance that Gary might have had some secret way of lining up the\naxis of those two antennas in his back yard.\n\nDom ( I8CVS) I still have your bench lab alignment pictures from years\nago.\nIt has been a long dry spell for us.\n\nAnd as usual Dr. Johnson (K0CQ) can add helpful information which we are\nall thankful for.\n\nMy problem as you all now can grasp is outdoors , far field , 23 feet\nabout ground using prime dish problems.\nAssuming good focus alignment on that dish and since it is AZ/EL mounted\nconstructing the measurement \nability on the selfsupporting tower 48 feet distant seems simple at first\nbrush.\nHowever the desire to have the measurement capability be no worse than\n1dB or the axial ratio results\nbegins to provide tight axis alignment of the bore sight even using a\nsingle spinning dipole.\n\nI apoligize again for stirring up a problem by not sending the second\npost to the BB\n\n73's\n\nJoe Murray K0VTY\n========================\n----- Forwarded Message -----\nFrom: Joe v Murray <[email protected]>\nTo: [email protected]\nDate: Thu, 10 Jun 2010 20:51:52 -0500\nSubject: Re: [Mw] Fwd: Power splitters-errors circular polarization?\n\nI have been trying to determine a way to accomplish the line up of the\ntwo axis\nbefore I begin the construction.\nKeeping  the entire system and measurement off the ground is a\nrequirement.\nAs we know on a CP antenna the minimum axial ratio is the measure that\nmust be delivered or \nthe notion of CP does not mean much.\nIn my case I am using a 54 inch diameter spun aluminum dish mounted at 23\nfeet off the ground.\nA mono axial mode helical feed is used with > 22 dB return loss. \nA second self supporting tower at 48 foot distant is the location for the\nmeasurement dipole system\nHowever so far I have not convinced myself of a sure fire way to manage\nthe axis alignment.\nEven when I make the measurement end adjustable I still have not arrived\nat a good enough way.\nSo when you came up with your suggestion I thought maybe you have devised\na method of aligning \nthose axis with in some reasonable method.\nI do not believe that eye balls will cut the needed accuracy if 1dB of\naxial ratio is the goal.\n\nI should have provided the above in the first place Gary\n\nThanks Gary\n\nJoe Murray K0VTY\n======================\nOn Thu, 10 Jun 2010 17:59:12 -0700 (PDT) Gary K Reed\n<[email protected]> writes:\nWell, I would say mount the dipole through a piece of PVC pipe of say 1\ninch diameter. Make the pipe 3 feet long. Run the pipe through a PVC\n\"Tee\" of appropriate size. Mount that \"Tee\" on a stand of some sort. I\nwould suggest more PVC for that - no metal of course.\nThen, site down through the pipe at the other antenna. Far field would be\nabout 25-30 feet at 1296  so you should be able to see that far easily.\n(Far field depends on the antenna aperture so it varies. Large arrays\nwould entail longer distances.)\n\nDon't know if this helps, but it might be a start.\n\nGary WE9Y\n--- On Thu, 6/10/10, Joe v Murray <[email protected]> wrote:\n\n\nFrom: Joe v Murray <[email protected]>\nSubject: Re: [Mw] Fwd: Power splitters-errors circular polarization?\nTo: [email protected], [email protected]\nDate: Thursday, June 10, 2010, 8:42 PM\n\n\nHi Gary\n\nAny good suggstions on how to keep the axis of the rotating dipole \nlined up with the axis of the CP antenna in the far field?\n\nThanks \n\nJoe Murray  K0VTY\n====================\nOn Thu, 10 Jun 2010 17:24:55 -0700 (PDT) Gary K Reed\n<[email protected]> writes:\n> To measure axial ratio, why not rotate a dipole in front of the yagis \n> (or other antenna) , and measure the signal strength. If the axial \n> ratio is 1 then there should be NO change in signal strength as the \n> dipole is rotated. It would necessary to stay in the far field.\n>  \n> Or have I been working too long today?\n>  \n> Gary WE9Y\n> _______________________________________________\n> Microwave mailing list\n> [email protected]\n> http://www.valinet.com/mailman/listinfo/microwave\n> \n> \n____________________________________________________________\nPenny Stock Jumping 2000%\nSign up to the #1 voted penny stock newsletter for free today!\nhttp://thirdpartyoffers.juno.com/TGL3141/4c1186ca9383d82045m03vuc\n",
    "attachments": []
}