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GET /hyperkitty/api/list/[email protected]/email/QPV4UIRG5YSG2X2NYCLZOJOD3HAQSKOF/?format=api
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/QPV4UIRG5YSG2X2NYCLZOJOD3HAQSKOF/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "[email protected]", "message_id_hash": "QPV4UIRG5YSG2X2NYCLZOJOD3HAQSKOF", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/35Y4RSZDXQ67N6FBW3UREN2EKETECT7V/?format=api", "sender": { "address": "ve9qrp (a) gmail.com", "mailman_id": "4d6061838db34aba9a1c4722addebfaf", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/4d6061838db34aba9a1c4722addebfaf/emails/?format=api" }, "sender_name": "Bruce Robertson", "subject": "[amsat-bb] Re: New Lindy's QRV", "date": "2010-02-09T02:42:52Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/35Y4RSZDXQ67N6FBW3UREN2EKETECT7V/?format=api", "children": [], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Being omnidirectional, this antenna offers no gain, so preamps are, in\nmy opinion, absolutely essential (at least on 70cm). Moreover, you\nneed to use one that has a proven low noise factor. For practical\npurposes , this means SSBUSA or ARR models.\n\nBy way of contrast, note the reception of AO-51 in the second half of\nthis videohttp://www.youtube.com/watch?v=XgNcCGXeRyw It's not great,\nbut its better than you describe, and I'm doing it indoors, with a\nsilly wire dipole made out of #12 copper wire. However, it's directly\nconnected to a preamp, and that makes all the difference.\n\nSimilarly, all the 70cm work in my videos is currently conducted with\na 1/4 wave vertical connected directly to an N-connector, up about 20'\nin the air, followed by 10' feet of LMR400 and a good low-noise\npreamp. The reason I'm building the lindy is to even out the pattern\ncompared to the vertical, which, of course, has deep nulls overhead\nand elsewhere in its elevation pattern. Despite that, HO-68's beacon\nis audible Q-5 from horizon to horizon for me even with the 1/4 wave\nvertical.\n\nWhile a preamp represents a considerable amount of money, the good\nnews is that the improvement from a preamp applies to any sort of\nantenna you might use or build, at least those to which it is\nconvenient to connect a preamp.\n\n73, Bruce\nVE9QRP\n\nOn Mon, Feb 8, 2010 at 8:26 PM, David Ek <[email protected]> wrote:\n> Question for anyone out there: I just built the parasitic Lindy from the\n> Feb 2010 QST. What kind of performance (on receive) should I expect from\n> it during, say, an AO-51 pass (max EL 83 deg)? I had my Kenwood TH-F6a\n> HT connected directly to it (only a few feet of RG-8X coax to the\n> antenna) with no preamp, and I only had good copy for a moment here and\n> there. Just wondering if I need a preamp or if I need to be suspicious\n> of my construction.\n>\n> tnx & 73,\n>\n> Dave NK0E\n>\n> -----------------\n>\n> Edward Cole wrote:\n> I forgot to add that these are patterned after Tony, AA2TX, designs\n> (UHF version is in Feb. 2010 QST).\n> My variation was to use pvc sched-40 plastic pipe (white).\n>\n> The preamp is one of the older DEMI designs that uses a mgf-1302\n> GasFet with about 0.7 dBNF. I see about one s-unit of noise when I\n> turn it on. There is 4-feet of RG-58 to the UHF Lindy and 60-feet to\n> the FT-847 from the preamp. The VHF Lindy has no preamp and is fed\n> with 60-feet of RG-213.\n>\n> The VHF Lindy brings up repeaters 70-miles away with 50w, and the UHF\n> Lindy hears repeaters that far away. So actually can make a nice\n> general purpose antenna.\n>\n> 73, Ed\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\n-- \nhttp://ve9qrp.blogspot.com\n\n", "attachments": [] }