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{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/WRZUZNR7JN7IYNWD2OTENUCPE5HF4CPH/",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/",
    "message_id": "[email protected]",
    "message_id_hash": "WRZUZNR7JN7IYNWD2OTENUCPE5HF4CPH",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/WRZUZNR7JN7IYNWD2OTENUCPE5HF4CPH/",
    "sender": {
        "address": "hans.bx2abt (a) msa.hinet.net",
        "mailman_id": null,
        "emails": null
    },
    "sender_name": "Hans (BX2ABT)",
    "subject": "[amsat-bb] Lindenblad or DCA???",
    "date": "2018-04-02T14:15:52Z",
    "parent": null,
    "children": [],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "Hello Joe,\n\nThanks for the reply, appreciate it.\n\nYes, the phasing harness is different, but my guess was that this \nshouldn't make a lot of difference as long as you get the 90 degree \nphase and the impedance right. If you look at the radiation patterns for \nboth then they are nearly identical, hence my question if they are not \none and the same thing.\n\nIt came up here because I have two DCAs right now, one for 2m, one for \n70cm, both RHCP, no pre-amps. I do hear some birds, but signals are very \nweak. The 2m one works fine when receiving the NOAA wx sats, so I was \nwondering if the 30 degree angle of the Lindenblad would be better for \namateur sats. I lack the knowledge to understand the difference between, \nwhat you say, the geosynchronous orbit of NOAA sats and the LEO orbits \nof our sats. NOAA wx sats are also LEO sats, not? I'll see if Google \nturns up something there.\n\nIt's easy for me to change the tilt of my DCAs to 30 degrees, so I'll \ntry that this week. Should be a nice experiment.\n\n73 de Hans\nBX2ABT\n\n\n> Hans,\n>\n> Here are links with antenna patterns for the DCA:\n>\n> https://drive.google.com/file/d/0B0Dkk87YYl-xX2gzLXk5MHZKVU0/view\n>\n> and the EZ-Lindenblad:\n>\n> http://www.amsat.org/wordpress/wp-content/uploads/2015/08/An-EZ-Lindenblad-Antenna-for-2-Meters2.pdf\n>\n> The difference is in the lengths of the \"RG-59 (75ohm) phasing harness\"\n> and dipoles to achieve a 50 ohm impedance at the required frequency.\n>\n> The angle of the crossbooms affects the directivity of the antenna, in\n> the examples given, 60 degrees for a NOAA satellite in a geosynchronous\n> orbit and 30 degrees for a LEO orbit.\n>\n> The only differences I see are the 50 ohm load feedpoint and the\n> Lindenblad dipoles are not exactly in the same plane as the DCA.\n>\n> -73, Joe Spier, K6WAO\n> President, AMSAT\n",
    "attachments": []
}