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GET /hyperkitty/api/list/[email protected]/email/WIMZZ2S4B35NWIDLSHVT2GC3U4RYA3FQ/?format=api
{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/WIMZZ2S4B35NWIDLSHVT2GC3U4RYA3FQ/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "[email protected]", "message_id_hash": "WIMZZ2S4B35NWIDLSHVT2GC3U4RYA3FQ", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/OILGPN425AJDTYDSAHZSXGVCCYNMAD4V/?format=api", "sender": { "address": "robert (a) k3rrr.com", "mailman_id": "4c878317ca874f668e48214c6598131f", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/4c878317ca874f668e48214c6598131f/emails/?format=api" }, "sender_name": "Robert", "subject": "Re: [amsat-bb] Cheap rotator setup", "date": "2018-12-20T05:56:04Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/OILGPN425AJDTYDSAHZSXGVCCYNMAD4V/?format=api", "children": [ "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/H7B6P5YABNKCZ75A7AZ2ES4HYK5LXTC2/?format=api" ], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "Hi Eli,\n\nI am the author of that webpage you're using for a guide for your own \nset up. I humbly appreciate that you have chosen the page for some \nguidance - that page is one of the Top 5 pages at my site so lots of \nfolks have successfully used it. Several of them have been pushing me to \nsubmit this to QST as an article which I may do (my last one was exactly \n30 years ago - so it may be time for the next one.)\n\n::::::::::::::::::::::::\nNote that I extensively edited the web page today so I genuinely am \nseeking additional help from all to help make this page even better and \nto give it more clarity or correct any technical errors - especially \nbefore I submit the page info to QST....\n::::::::::::::::::::::::\n\nEli, as a result of your question, I just added the below info to the \nweb page - along with a slider that shows 31 new photos that give more \ndetails and a detailed diagram of the antenna's beamwidth....check out \nthe page for more info since those cannot be shown here...but for those \nwho don't want to look, here is a highlight quote from the page to \nhopefully answer Eli's question.\n\n--------------------------------------\n\n“Why Are You Using a 45° Angle for Fixed Elevation Instead of the \nRecommended 15°?”\n\nI thought I had better add a comment as to why I am obviously using a \n45° angle instead of the recommended 15°.\n\nI am personally surrounded by RF eating 65 foot trees and a RF eating \ntwo-story house. As a consequence, I chose to move the A430S10 50° \nantenna beamwidth (see below) and center them on a fixed 45° instead of \n15°.\n\nOstensibly, I would lose coverage from 0° to 20° (45° center angle minus \nhalf of the 50° beamwidth of the antennas, or 25° = 20° ) by doing this \n– but I’m going to lose those angles (and then some) anyway because of \nthe tree and house QRM.\n\nTrust me when I tell you that trees and houses do a damnably good job of \nblocking RF at satellite frequencies – in my case below 30° in summer \nand 22° in winter! (This is going to be one of my next videos on my \nYouTube channel at http://Youtube.com/K3RRR.)\n\nBeamwidth is loosely defined as the width of the main lobe of radiation \nfor both transmit and receive. This is a whole discussion by itself but \nfor my cheapie antenna system, you’re better off with a wide beamwidth \nversus a more narrow beamwidth for your antennas. The following diagram \nfrom Diamond Antennas shows the comparison of what that width of the \nmain lobe looks like with my orange arrows showing where they cross the \n3 db points.\n\nIf you kinda sorta extrapolate, you can see that an imaginary line from \nthe 3 db intersection point to the outer circle would translate to about \n25° either side of the zero mark – for a total spread from both sides \nequal to about 50° of beamwidth. (The other chart shows the same info \nfor Diamond’s bigger brother the A430S15 – 15 elements instead of 10. \nyou can see how much narrower the beamwidth is albeit with not that much \ndifference in gain.)\n\nIn more technical terms, the A430S10 has an E-Plane 3 dB Beamwidth = 50 \ndegrees. In layman’s language, this means that you will have a good \nreceive AND transmit signal 25° above and 25° below your center angle – \nwhich in my case is 45° due to the constraints of Home Depot.\n\nHome Depot?\n\nI picked 45° because Home Depot sells PVC connectors for that angle – \nand only that angle since 90° angles really are not that useful for the \nhamsats!\n\nAgain, with these antennas having a 50° beamwidth, my setup handled \npasses between 20° and 70°. This same wide beamwidth also makes pointing \nthe antenna more forgiving – which is important for cheap rotators which \nare not all that accurate between calibrations.\n\n(The E-Plane 3 dB Beamwidth = a whopping 95 degrees for the A144S5 two \nmeter five element Yagi – so it was not the limiting consideration.)\n\nBut enough about me and why I chose 45°. Let’s talk about you and your \nneed for 15°.\n\nPermanently Bending Schedule 40 PVC With My Wife’s Help\n\nI need to plagiarize myself and steal a couple of paragraphs I have on \nthis other webpage on my site:\n\nAttic AMSAT Antenna – Working the Ham Radio Satellites With A Rotatable, \nComputer Controlled, Yagi Attic Antenna\n\n“If you have played with PVC for antennas for a while you will already \nknow they don’t make 15° connectors. So, I was faced with trying to bend \na straight piece PVC – which I thought was going to be difficult.\n\n“As it turns out, it is surprisingly trivial to heat even Schedule 40 \nPVC so that it becomes bendable with a standard 1500 watt hair dryer in \nless than 10 minutes of your time! (Thanks to YouTube for this education!)”\n\nWife Jan’s hair dryer actually had some attachments and gizmos which \nfocused the heat better than mine so I swiped hers for this task. She \nwas surprisingly unamused and recommended I get a heat gun for future \napplications. I obediently followed her recommendation and got this \nparticular heat gun.\n\nSomething about briar patches came to mind for some reason – even though \nthere was no mention in the Amazon description.\n\n--------------------------------------\n\nEli, I have just now added the above information to the cheap antenna \npage – I appreciate the heads up on helping make this clearer for other \nfolks too.\n\nHope this helps...and hope to work you on the birds soon!\n\n73,\n\nRobert K3RRR\n\n -.- ...-- .-. .-. .-.\n73 de Robert K3RRR\nhttp://K3RRR.com\n@K3TripleR\nhttp://YouTube.com/K3RRR\n-.- ...-- .-. .-. .-.\n\nOn 12/17/2018 6:37 PM, Eli Caul wrote:\n> Hi folks -\n>\n> In my ongoing effort to figure out how to use the SSB satellites, I duplicated this setup over the weekend:\n>\n> http://k3rrr.com/cheap-computer-controlled-tv-rotor-for-amsat-satellites-and-includes-free-satellite-tracking-with-pstrotator-and-the-usb-uirt/\n>\n> I bought a list of materials based on the photograph, and it didn't occur to me that the PVC parts pictured put the antennas at approximately 45 degrees and not the recommended 15 degrees.\n>\n> Has anyone done this setup? If so, how did you assemble it so that the antennas ended up at the recommended angle?\n>\n> There were a couple of higher angle passes yesterday (one was at 50 degrees) but so far I haven't been able to 'loop' the satellite. I'm using a Yaesu FT-991A for uplink and an Airspy SDR on the downlink.\n>\n> Advice appreciated. So far I've gotten some excellent advice from AMSAT members and I really appreciate the groups level of expertise and patience with my fundamental questions.\n>\n> 73 de KK6ZHZ,\n>\n> - Eli Caul\n>\n> Director of Customer Care\n> Sonic\n> 707-237-6201 Direct\n> 707-521-0131 Faxline\n>\n>\n\n", "attachments": [] }