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21. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Artek Manuals <Manuals@ArtekManuals.com>; Date: Sat, 22 May 2021 11:24:45 -0400; Steve et all So what is the "penalty" in DB (gain) for the using the increased bandwidth settings on this beam vs an optimized for gain approach? For the sake of discussion ignore the F/B degradation; /archives//html/Towertalk/2021-05/msg00093.html (14,212 bytes)
22. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: k7lxc--- via TowerTalk <towertalk@contesting.com>; Date: Sat, 22 May 2021 15:42:52 +0000 (UTC); _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk; /archives//html/Towertalk/2021-05/msg00094.html (9,540 bytes)
23. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Richard Smith <n6kt1@sbcglobal.net>; Date: Sat, 22 May 2021 15:54:55 +0000 (UTC); Hi Steve, Your suggestion sounds very reasonable. One question: I have read multiple times that the electrical connections between the coils and the aluminum tubing can be an issue over time. Has a g; /archives//html/Towertalk/2021-05/msg00095.html (9,878 bytes)
24. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: "Lux, Jim" <jim@luxfamily.com>; Date: Sat, 22 May 2021 09:00:02 -0700; On 5/22/21 8:42 AM, k7lxc-- via TowerTalk wrote: Sorry, but I don't believe any of that.? It sounds purely anecdotal. Anecdotal?!? Ha - most of the stuff you get here is anecdotal along with lo; /archives//html/Towertalk/2021-05/msg00096.html (10,969 bytes)
25. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: <k1ttt.dave@gmail.com>; Date: Sat, 22 May 2021 12:08:45 -0400; I had stacked 40-2cd's years ago. Both exhibited intermittent connections on the reflector coil connections resulting in fluctuating swr. I 'assume' the driven element didn't show that problem becaus; /archives//html/Towertalk/2021-05/msg00097.html (10,542 bytes)
26. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: VE6WZ_Steve <ve6wz@shaw.ca>; Date: Sat, 22 May 2021 15:36:27 -0600; Dave et al, This has drifted off topic, but I dug out my 4NEC2 Cushcraft XM-240 models and coil calculations. (please be aware I have not checked the details of this modelling since I did it some tim; /archives//html/Towertalk/2021-05/msg00098.html (11,981 bytes)
27. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Jeff Blaine <KeepWalking188@ac0c.com>; Date: Sat, 22 May 2021 17:13:29 -0500; Picking the "right" 40m beam is hard. So I appreciate the struggles the OP is going through. I went through this same process when putting up a 40m tower a couple of years back. 40m seemed the toug; /archives//html/Towertalk/2021-05/msg00099.html (12,491 bytes)
28. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Artek Manuals <Manuals@ArtekManuals.com>; Date: Sat, 22 May 2021 19:19:13 -0400; Steve Thanks for the proper proper analysis...8^) Ignoring possible SWR losses as many will unlikely go to your due diligence on matching which I applaud..I would argue that .5 to 1.3db is hardly wor; /archives//html/Towertalk/2021-05/msg00100.html (14,917 bytes)
29. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: VE6WZ_Steve <ve6wz@shaw.ca>; Date: Sat, 22 May 2021 19:30:49 -0600; Dave Indeed few will be motivated to implement a complex in-band switching system, but if you are a home brew antenna builder, its not that difficult, but it is NOT plug-and play. I like to build ant; /archives//html/Towertalk/2021-05/msg00106.html (18,663 bytes)
30. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: VE6WZ_Steve <ve6wz@shaw.ca>; Date: Sun, 23 May 2021 08:29:02 -0600; I have received a few direct email questions about this thread.. Just to be clear, the reason for inductor switching at the Yagi elements is NOT only to get a good, low SWR" match at the driver. The; /archives//html/Towertalk/2021-05/msg00109.html (20,827 bytes)
31. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: "Richard (Rick) Karlquist" <richard@karlquist.com>; Date: Sun, 23 May 2021 09:40:18 -0700; The SWR and matching at the feedpoint is really NOT the issue. The real issue is tuning the REFLECTOR across the band. That is what determines the gain and F/B performance. The PARASITIC element need; /archives//html/Towertalk/2021-05/msg00110.html (10,886 bytes)
32. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: David Gilbert <ab7echo@gmail.com>; Date: Sun, 23 May 2021 11:12:39 -0700; Exactly! I'm not in favor of turning listservers into groups.io forums, but it would be nice somehow to have a sticky list of antenna myths (with explanations) to counteract the misinformation that p; /archives//html/Towertalk/2021-05/msg00112.html (10,061 bytes)
33. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Sun, 23 May 2021 12:11:08 -0700; YES! SWR is NOT an indicator of antenna performance. 73, Jim K9YC The SWR and matching at the feedpoint is really NOT the issue. The real issue is tuning the REFLECTOR across the band. That is what; /archives//html/Towertalk/2021-05/msg00113.html (11,218 bytes)
34. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Jeff Blaine <KeepWalking188@ac0c.com>; Date: Sun, 23 May 2021 15:20:03 -0500; Ah, but it can be, just not in the way guys generally think about... A 2 element beam gain increases with coupling. And that in turn drives the feedpoint Z downward. In fact this characteristic can; /archives//html/Towertalk/2021-05/msg00114.html (13,292 bytes)
35. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Mike Zak <mike@brookblue.com>; Date: Sun, 23 May 2021 20:31:22 +0000; Is there a paper, article, YouTube video, Powerpoint deck, chapter in a book, website, message-in-a-bottle, or anything else, that clearly and succinctly describes the trade-offs and interactions bet; /archives//html/Towertalk/2021-05/msg00115.html (12,601 bytes)
36. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: "Lux, Jim" <jim@luxfamily.com>; Date: Sun, 23 May 2021 13:43:40 -0700; A 15 minute session with EZNEC, and a candidate yagi design, is plenty adequate for showing that theres some serious systems engineering involved in coming up with the right set of trade-offs, starti; /archives//html/Towertalk/2021-05/msg00116.html (11,909 bytes)
37. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Sun, 23 May 2021 13:50:28 -0700; Hi Jeff, No question that SWR changes with several elements of design, and a good match in the shack is needed to make some power amps happy. I'm no Yagi design guru, but I've done a few for special; /archives//html/Towertalk/2021-05/msg00117.html (14,697 bytes)
38. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: VE6WZ_Steve <ve6wz@shaw.ca>; Date: Sun, 23 May 2021 14:41:46 -0600; Mike, I plan to make YouTube video about this, but did you read the modelling section of my 80-40m Yagi paper? Perhaps that is exactly the message in the bottle if you are looking for? https://drive.; /archives//html/Towertalk/2021-05/msg00118.html (14,914 bytes)
39. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: "Peter Voelpel" <dj7ww@t-online.de>; Date: Sun, 23 May 2021 23:10:41 +0200; Everything can be calculated and designed with help of EZNEC. That's what I did for my 3-element fullsize yagi which works very well for me. I optimized it for best front to back within the most acti; /archives//html/Towertalk/2021-05/msg00119.html (13,832 bytes)
40. Re: [TowerTalk] OptiBeam OB2-40M (score: 1): Author: N4ZR <n4zr@comcast.net>; Date: Sun, 23 May 2021 18:52:43 -0400; The only thing I know of is K7LXC/N0AX's tribander test which was done a long time ago, like in 1998. Because of that, many of the antennas in the test have been superseded, and if anyone is masochi; /archives//html/Towertalk/2021-05/msg00123.html (13,393 bytes)

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