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141. [Towertalk] Re: Insulated Wire (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Thu, 3 Oct 2002 21:49:23 -0400; Yes and no; but mostly no. Coaxial cable has a velocity factor significantly less than one, and equal to one divided by the square root of the dielectric constant of the insulating material that fill; /archives//html/Towertalk/2002-10/msg00118.html (9,543 bytes)
142. [Towertalk] GAO Challenger DX (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Sun, 6 Oct 2002 22:03:47 -0400; Agreed. As you can read in U S Army Signal Corp manuals, calculate by means of NEC-4, and/or prove for yourself by experiment, for DX (as opposed to short-range ground-wave work) a horizontal dipole; /archives//html/Towertalk/2002-10/msg00201.html (8,240 bytes)
143. [Towertalk] GAO Challenger DX (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Mon, 7 Oct 2002 13:52:25 -0400; I simulated vertical dipoles with NEC-4. See below. The heights I looked at with NEC-4 did not exceed one-half wavelength, so the length of the vertical dipole was constrained not to exceed one-half; /archives//html/Towertalk/2002-10/msg00223.html (10,943 bytes)
144. [Towertalk] GAO Challenger DX (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Mon, 7 Oct 2002 14:10:57 -0400; Let's compare a vertical with a horizontal dipole at the same max. height of, say, 70 ft. NEC-4 says, for * f = 3.5 MHz; * vertical dipole top height = 70 ft (21.336 m) and bottom height = 2 m; * my; /archives//html/Towertalk/2002-10/msg00224.html (9,245 bytes)
145. [Towertalk] Large Ferrite Beads? (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Mon, 7 Oct 2002 14:20:23 -0400; In April 2002, Amidon quoted to me: Fair-Rite Amidon _Dimensions (inches)_ _AsubL__ Price Part No. No. (????) Qty. O.D. I.D. Thick (nH/T^2) (each) -- -- -- -- -- -- -- -- 5977006401 FT-100-77 200 1.0; /archives//html/Towertalk/2002-10/msg00225.html (7,999 bytes)
146. [Towertalk] GAO Challenger DX (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Mon, 7 Oct 2002 15:27:00 -0400; Billy Cox <aa4nu@ix.netcom.com> has complained that I have not compared a 1/2w horizontal dipole to a 1/2w vertical for f = 3.5 MHz, so here is the result of that comparison. NEC-4 says, for * f = 3.; /archives//html/Towertalk/2002-10/msg00229.html (9,553 bytes)
147. [Towertalk] GAO Challenger DX (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Mon, 7 Oct 2002 16:06:29 -0400; OK; here are NEC-4 results for two "half-wavelength" (actually 10.1-m long) dipoles for f = 14 MHz: one vertical with its bottom one full free-space wavelength, i.e., 21.414 meters above my New Engla; /archives//html/Towertalk/2002-10/msg00232.html (9,428 bytes)
148. [Towertalk] GAO Challenger DX (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Mon, 7 Oct 2002 17:12:22 -0400; You said "let's keep the models as close as possible," which sounded to me like a complaint -- and a **fair** complaint -- that comparing antennas of unequal lengths was unfair (even though I had des; /archives//html/Towertalk/2002-10/msg00238.html (11,098 bytes)
149. [Towertalk] Feeding longwire with coax (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Tue, 8 Oct 2002 11:10:53 -0400; Yes, it does. The balanced line should be an odd number of quarter wavelengths long, and if the antenna and feedline are tuned correctly, the balanced line can be connected to an unbalanced tuner out; /archives//html/Towertalk/2002-10/msg00263.html (7,545 bytes)
150. [Towertalk] choices (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Wed, 9 Oct 2002 01:14:48 -0400; It's not _all_ bad. My G5RV in the shape of an inverted "U" only 30 feet high and my friend W1NU's G5RV in the shape of an inverted "V" 55 feet high at its apex both work well on both 80 and 40 meter; /archives//html/Towertalk/2002-10/msg00288.html (8,388 bytes)
151. [Towertalk] Large Ferrite Beads? (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Wed, 9 Oct 2002 10:37:37 -0400; Yes, certainly. Just keep in mind the smaller choking impedance of a one-turn "winding" on a "toroid," which is thinner than a "bead." E.g.: One "turn" through an FT-140-77 toroidal core (actual meas; /archives//html/Towertalk/2002-10/msg00297.html (8,740 bytes)
152. [Towertalk] choices (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Wed, 9 Oct 2002 13:24:15 -0400; I know; I read that article, and we've all seen or heard examples, sometimes first-hand, of contacts made with practically no antenna. And I agree with you that it pays to have multiple antennas, and; /archives//html/Towertalk/2002-10/msg00303.html (11,350 bytes)
153. [Towertalk] Choices (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Wed, 9 Oct 2002 14:32:44 -0400; Yes. Mainly, the higher, the better. And the higher the co$t. -Chuck, W1HIS; /archives//html/Towertalk/2002-10/msg00307.html (8,444 bytes)
154. [Towertalk] choices (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Wed, 9 Oct 2002 17:09:57 -0400; NEC-4 can model every detail that you've mentioned, and many more, e.g., insulation on the wire, both lumped and distributed loading, and traps. If you know what you're doing, it works. I've modeled; /archives//html/Towertalk/2002-10/msg00318.html (10,189 bytes)
155. [Towertalk] Choices (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Wed, 9 Oct 2002 17:15:00 -0400; 1. We East Coast guys work Central, South, and Southeast Asia through the aurora. Sometimes western Asia, too. 2. The path from MA to the UK is often in the radio aurora. It was for much of the last; /archives//html/Towertalk/2002-10/msg00319.html (8,549 bytes)
156. [Towertalk] choices (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Thu, 10 Oct 2002 01:03:33 -0400; Thank you for making this important point, although "any" may be a slight overstatement. You are correct that, if an antenna is more than a half-wavelength long, then bending it (e.g., into an invert; /archives//html/Towertalk/2002-10/msg00340.html (9,872 bytes)
157. [Towertalk] Balun Location (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Thu, 10 Oct 2002 11:28:18 -0400; The boom will be a big fat shorted turn, so to some extent it will spoil the choke, but winding coax around the boom on a form should still work if the diameter of the form is much greater than (say,; /archives//html/Towertalk/2002-10/msg00355.html (7,801 bytes)
158. [Towertalk] Balun Location (more) (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Thu, 10 Oct 2002 12:22:28 -0400; To which I replied: "The boom will be a big fat shorted turn, so to some extent it will spoil the choke, but winding coax around the boom on a form should still work if the diameter of the form is mu; /archives//html/Towertalk/2002-10/msg00356.html (8,546 bytes)
159. [Towertalk] Riveting (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Fri, 11 Oct 2002 17:25:21 -0400; I understand that the telescoping Al-tubing pieces of a Force 12 antenna are riveted together. Do the instructions for assembling a Force 12 antenna include applying some kind of oxidation-inhibiting; /archives//html/Towertalk/2002-10/msg00411.html (6,606 bytes)
160. [Towertalk] Balun Location (score: 1): Author: ccc@space.mit.edu (Chuck Counselman); Date: Fri, 11 Oct 2002 17:28:31 -0400; Remember to wind counter-clockwise on that munimula.; /archives//html/Towertalk/2002-10/msg00412.html (7,291 bytes)

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