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61. TopBand: Ducting (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 8 Jul 1997 20:48:06 +0000; To: <topband@contesting.com> Hi Bob, I think you and I both agree ducting is speculative, and can not be measured. Since it can not be measured, we can't know many exact dimensional quantities. At t; /archives//html/Topband/1997-07/msg00033.html (13,961 bytes)
62. TopBand: Re: Why the duct? (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 8 Jul 1997 20:48:06 +0000; Hi Yuri, To: <topband@contesting.com> Are you sure the ionosphere is affected by updrafts from the condition or type of earth below it? Do these vertical updrafts cut through the trade winds and jet; /archives//html/Topband/1997-07/msg00034.html (9,211 bytes)
63. TopBand: Light Dimmer Noise (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 8 Jul 1997 20:48:06 +0000; Hi Chip, The reason they don't help is if you shield an antenna from the time varying electric field you also shield it for any time varying magnetic fields or radiation fields. All shielding does i; /archives//html/Topband/1997-07/msg00035.html (9,392 bytes)
64. TopBand: Re: Why the duct? (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 9 Jul 1997 09:03:15 +0000; To: <topband@contesting.com> What is the change in dielectric constant with temperature of air at 1.8 MHz? Does the two meter signal refract or duct because of temperature changes, or MOISTURE layer; /archives//html/Topband/1997-07/msg00040.html (10,341 bytes)
65. TopBand: Shielding (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 9 Jul 1997 09:03:15 +0000; To: <topband@contesting.com> The type of material, magnetic or not, only affects the resistivity of the material at RF. Eddy currents prevent magnetic effects from taking place no mater what the mat; /archives//html/Topband/1997-07/msg00041.html (11,892 bytes)
66. TopBand: Vertical antenna phasing (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 16 Jul 1997 14:21:16 +0000; To: <topband@contesting.com> And probably not work very well. Hi Steve, The key is in two areas. One area is keeping the current UNIFORM in the vertical (that requires top loading) and loading losse; /archives//html/Topband/1997-07/msg00062.html (8,983 bytes)
67. TopBand: Three eighths wave inv-L (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 29 Jul 1997 09:38:03 +0000; To: <topband@contesting.com> Hi Steve, That's a pretty poor ground to use if you have room for radials. Everyone in VK has a ten thousand acre ranch, don't they? ;-) That's strange. Assuming an even; /archives//html/Topband/1997-07/msg00111.html (10,104 bytes)
68. TopBand: Elevation Angle of Maximum Radiation from Verticals (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 30 Jul 1997 10:48:36 +0000; Hi Earl, Good to hear you again! I was thinking of the early W5RTQ articles about shunt feeding towers when the topic came up. To: <topband@contesting.com> Be careful using NEC based programs to dete; /archives//html/Topband/1997-07/msg00127.html (10,768 bytes)
69. TopBand: Elevation Angle of Maximum Radiation (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 30 Jul 1997 10:48:36 +0000; To: <topband@contesting.com> I has the same results using BC arrays. The 250 ft -300 ft verticals stunk, my 1/4 vertical would beat them. I find the same effect on 80 meters. A low incident angle gr; /archives//html/Topband/1997-07/msg00128.html (8,090 bytes)
70. TopBand: Elevation Angle of Maximum Radiation from Verticals (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 30 Jul 1997 12:08:32 +0000; To: <topband@contesting.com> You should be surprised Bob. A vertical antenna's radiation angle is affected very little by a near field radial system. The only exception would be if the radials were a; /archives//html/Topband/1997-07/msg00133.html (8,420 bytes)
71. TopBand: 160m shunt feeds (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Thu, 31 Jul 1997 09:44:11 +0000; To: <topband@contesting.com> Hi Carl, The inductive reactance of an additional #12 wire fifty or a hundred feet high can be pretty high, requiring a large amount of capacitive reactance ( a low valu; /archives//html/Topband/1997-07/msg00145.html (13,231 bytes)
72. TopBand: Slinky Beverage (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Thu, 31 Jul 1997 14:50:36 +0000; To: <topband@contesting.com> Hi Pete, I played around with slow wave structures (which is what that would be) in the 70's. Coiling the wire does several things. One thing is it increases the phase d; /archives//html/Topband/1997-07/msg00148.html (8,917 bytes)
73. TopBand: Radial current (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 4 Jun 1997 23:25:37 +0000; I have some questions and comments, naturally. ;-) How on earth (no pun intended) do you get a "radial near zero impedance"? There is no such thing unless it is lossless. If the radial is lossless, t; /archives//html/Topband/1997-06/msg00014.html (12,695 bytes)
74. TopBand: Radial current (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Thu, 5 Jun 1997 14:03:11 +0000; Hi Ward, If I understand correctly, you wonder what would happen if earth effects were uniform, and the current unbalance was due to length or placement of the radials. Let's look at the case of two; /archives//html/Topband/1997-06/msg00016.html (8,721 bytes)
75. TopBand: Another great Beverage idea (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 23 Jun 1997 15:08:30 +0000; I haven't read the page, but someone mention a web page somewhere had a funny description of how to guesstimate termination impedance. On rec.radio,amateur.antenna someone mention mentioned a web pa; /archives//html/Topband/1997-06/msg00051.html (11,054 bytes)
76. TopBand: VK3IO loud (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 30 Jun 1997 09:09:58 +0000; VK3IO was loud at sunrise, but only R 2-3 because of thunder showers to my west. Some Europeans were in pretty well also, so the band is still open. Must be summer ducting, from morning fog ;-) 73, T; /archives//html/Topband/1997-06/msg00063.html (6,759 bytes)
77. TopBand: Top Hat Loaded Verticals (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Thu, 1 May 1997 08:14:30 +0000; I do the same thing on 80 Carl. My 35 ft 80 meter vertical compares quite well against a 130 ft long dipole up at 130 ft on 80. I use about 60 radials 70 feet long on 80. In Sylvania Ohio, I used th; /archives//html/Topband/1997-05/msg00001.html (7,384 bytes)
78. TopBand: Re:Folded elements (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Thu, 1 May 1997 15:53:59 +0000; Hi Joe, Accelerating charges cause radiation. If an antenna has half the length, we need twice the charge acceleration to radiate the same power. If we move twice the charges past a given point, we h; /archives//html/Topband/1997-05/msg00004.html (10,486 bytes)
79. TopBand: Split Gorunds for Folded Feed Verticals? (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Fri, 2 May 1997 09:31:28 +0000; Hi Jim, I expect this thread to be censored at any moment, but hopefully we can come to some resolution. I think understanding HOW antenna's work is very important to 160 operators. It's the last ban; /archives//html/Topband/1997-05/msg00007.html (9,572 bytes)
80. TopBand: ARRL uncommitted (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Fri, 23 May 1997 20:35:56 +0000; A SSB sub-band also makes sense for regular rag chewing. Every other band has one, even the new WARC bands where SSB is permitted. Even VHF bands. Instead, CW operators are supposed to suffer on 160; /archives//html/Topband/1997-05/msg00086.html (8,624 bytes)

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