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1. Re: [TowerTalk] How Helically Wound Verticals Really Work (was : Vertical dipoles) (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Thu, 19 Nov 2009 15:12:23 -0800; YES! The problem, of course, is that you may need both, in which case I would use as much top loading as possible (multiple wires, longer) and add some inductance near the top of the vertical section; /archives//html/Towertalk/2009-11/msg00371.html (9,304 bytes)
2. Re: [TowerTalk] Vertical Dipoles (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Wed, 18 Nov 2009 08:55:37 -0800; The relevance is a practical one. Let's say I have a rope in a pulley at 100 ft (or a tower that I can climb) and I want to support an antenna, and I have no other supports (or at least nothing high); /archives//html/Towertalk/2009-11/msg00323.html (8,354 bytes)
3. Re: [TowerTalk] Vertical dipoles (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Wed, 18 Nov 2009 08:44:23 -0800; YES! AND it has gain in the horizontal plane. The ground reflection from a vertical dipole is FAR less beneficial than it is from a vertical monopole or horizontal dipole. 73, Jim K9YC ______________; /archives//html/Towertalk/2009-11/msg00322.html (7,680 bytes)
4. Re: [TowerTalk] Vertical dipoles (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Tue, 17 Nov 2009 22:45:08 -0800; Hold on a minute -- I think we are talking about very different antennas. :) I have a top-loaded vertical (some would call it a monopole) for 160M that works a treat, but it is not a DIPOLE. It's an; /archives//html/Towertalk/2009-11/msg00310.html (8,917 bytes)
5. Re: [TowerTalk] Vertical dipoles (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Tue, 17 Nov 2009 22:08:36 -0800; I'm missing a lot in your email. First, you say you're talking about a vertical dipole for 160M, and that the highest point is 55 ft. How can that be? A half wave on 160M is 80M, which is about 260 f; /archives//html/Towertalk/2009-11/msg00309.html (9,108 bytes)
6. Re: [TowerTalk] Vertical dipoles (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Tue, 17 Nov 2009 11:58:29 -0800; dipole Michael, This IS a "regular vertical dipole," it behaves exactly the same as if it were a horizontal dipole and coax turned on its side, except that it needs only one support, not two. Rudy's; /archives//html/Towertalk/2009-11/msg00300.html (9,049 bytes)
7. Re: [TowerTalk] Vertical dipoles (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Tue, 17 Nov 2009 08:23:12 -0800; Take a look at N6LF's website, which shows an interesting method. Then look at http://audiosystemsgroup.com/NCDXACoaxChokesPPT.pdf which shows my variation of that method using ferrite chokes. 73, Ji; /archives//html/Towertalk/2009-11/msg00296.html (7,323 bytes)
8. Re: [TowerTalk] power requirements (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Tue, 17 Nov 2009 00:03:26 -0800; WAY off the topic of towers, so I'll make it brief. Try to do as much as possible with 12V equipment and 12V power. Inverters waste efficiency and make lots of RF noise. No problem with finding good; /archives//html/Towertalk/2009-11/msg00286.html (7,278 bytes)
9. Re: [TowerTalk] Single point ground (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Wed, 04 Nov 2009 07:46:09 -0800; That's the right way to do it! If you simply disconnect on the other side of the panel (leaving the antennas ungrounded), there's always the chance (and a good chance) that a strike will find it's wa; /archives//html/Towertalk/2009-11/msg00110.html (9,329 bytes)
10. Re: [TowerTalk] Single point ground (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Wed, 04 Nov 2009 07:38:02 -0800; The electrician who wired small building that houses my shack here in CA did something almost as dumb, but on a smaller scale. That's one of the things I fixed. 73, Jim K9YC _________________________; /archives//html/Towertalk/2009-11/msg00109.html (8,586 bytes)
11. Re: [TowerTalk] Single point ground (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Tue, 03 Nov 2009 20:59:53 -0800; Yes, BUT: Don't use that circuitous route through the attic, because lightning won't follow it. Lighting will take the lowest impedance path, which is usually the shortest one. DO bond everything tog; /archives//html/Towertalk/2009-11/msg00096.html (8,014 bytes)
12. Re: [TowerTalk] RFI to HF rig (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Mon, 02 Nov 2009 20:38:03 -0800; There is an RFI reflector on contesting.com. If you ask this question there, you will get great answers. In general, LCD TVs are good, Plasmas are bad. This is the first I've heard about DLP, one way; /archives//html/Towertalk/2009-11/msg00053.html (8,428 bytes)
13. Re: [TowerTalk] 10m OWA 24' (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Mon, 02 Nov 2009 14:52:17 -0800; Yes, BUT -- there are two nice pieces of software on CD that comes with the ARRL Antenna Book that make it easy to solve this. One is called "SCALE" I think -- it's a DOS program that lets you scale; /archives//html/Towertalk/2009-11/msg00036.html (7,941 bytes)
14. Re: [TowerTalk] Antennas for a restricted space (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Sat, 31 Oct 2009 01:21:44 -0700; You're right, the 3-el SteppIR looks big on a 42 ft lot. :) But so would any other small tribander. Don't rule out the 2-el SteppIR. I'd bet it will work as well as most small tribanders, and it's sm; /archives//html/Towertalk/2009-10/msg00491.html (7,649 bytes)
15. [TowerTalk] RG218 (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Fri, 30 Oct 2009 10:53:56 -0700; I have the opportunity to buy some RG218 made by Times. Can anyone tell me about this cable? I know it's 50 ohms, 7/8-inch, PVC-II jacket, and 0.9dB/100 ft at 100 MHz. Is anyone using this stuff? Wha; /archives//html/Towertalk/2009-10/msg00476.html (6,499 bytes)
16. Re: [TowerTalk] Log periodic antennas and front end overload? (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Sun, 25 Oct 2009 17:04:22 -0700; It should not be a big deal. But -- it really comes down to the front end of your receiver. Buy a good one and you have no worries! 73, Jim K9YC _______________________________________________ ______; /archives//html/Towertalk/2009-10/msg00427.html (7,528 bytes)
17. Re: [TowerTalk] Verticals over sloping ground (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Sat, 24 Oct 2009 18:02:23 -0700; Don't worry about it. The terrain that matters is not the near field, but in the first 5 miles or so running radially from your QTH. My 160M vertical is ground mounted with about 70 radials that vary; /archives//html/Towertalk/2009-10/msg00424.html (8,372 bytes)
18. Re: [TowerTalk] Single point ground question (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Fri, 23 Oct 2009 12:32:54 -0700; The forum moderator is absolutely correct. Several fundamental principles apply. First, ALL grounds MUST be bonded together for safety, and they should be bonded together by the shortest practical pa; /archives//html/Towertalk/2009-10/msg00414.html (8,694 bytes)
19. Re: [TowerTalk] Please remove my address from the list (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Fri, 23 Oct 2009 09:49:32 -0700; Yes. All the good email programs make it easy to sort incoming mail into folders. I subscribe to nearly a dozen email lists. Each comes into it's own folder, and I read them when I have time. I do NO; /archives//html/Towertalk/2009-10/msg00407.html (8,865 bytes)
20. Re: [TowerTalk] Verticals Above Beams (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Fri, 23 Oct 2009 07:51:09 -0700; I had one on the roof of a Chicago apartment that I rented for 20 years between '67 and '86. I was pretty happy with it. 73, Jim K9YC _______________________________________________ _________________; /archives//html/Towertalk/2009-10/msg00402.html (8,083 bytes)

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