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Total 288 documents matching your query.

201. Re: [TowerTalk] Noob question re: Thrust Bearings (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Sun, 10 May 2020 20:49:33 -0500
3D printer. K5UJ _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/li
/archives//html/Towertalk/2020-05/msg00059.html (8,439 bytes)

202. Re: [TowerTalk] HST4-50 Heliax (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Thu, 14 May 2020 06:25:23 -0500
If that is truly an air dielectric coax, meaning a helical spiral structure instead of foam dielectric, then it has to be pressurized or run with a dryer if it's outside. An air dielectric 1/2 inch l
/archives//html/Towertalk/2020-05/msg00078.html (7,197 bytes)

203. [TowerTalk] Insuramce (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Sat, 23 May 2020 05:23:00 -0500
The purpose of a policy on hour home and other structures on your land is to cover catastrophic loss. Examples: Fire, a large tree falling on your home, destruction from earthquake, tornado, (your ro
/archives//html/Towertalk/2020-05/msg00138.html (7,508 bytes)

204. Re: [TowerTalk] NVIS (not exactly towers, but HF) (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Tue, 9 Jun 2020 09:39:09 -0500
I didn't see anything in the abstract that made me want to read it as far as ham radio is concerned. A number of hams over the past years have cited military work with cloud burners as a justificatio
/archives//html/Towertalk/2020-06/msg00037.html (7,522 bytes)

205. [TowerTalk] NVIS (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Fri, 12 Jun 2020 06:02:48 -0500
Yeah, how about some frequencies to go with those height measurements? Rob K5UJ _______________________________________________ _______________________________________________ TowerTalk mailing list
/archives//html/Towertalk/2020-06/msg00077.html (7,729 bytes)

206. Re: [TowerTalk] NVIS (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Fri, 12 Jun 2020 06:08:35 -0500
The problem with these antennas (one problem at least) is when they are used by hams who don't understand the lack of reciprocity between transmitting and receiving when using them. They hear great b
/archives//html/Towertalk/2020-06/msg00078.html (8,462 bytes)

207. Re: [TowerTalk] Inverted Vees (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Mon, 15 Jun 2020 05:55:17 -0500
Inverted Vs are compromise antennas in most cases compared to flat top dipoles. The ARRL hyped the inverted V in handbooks claiming its advantage with a 50 ohm Z (as if 75 ohms would make an antenna
/archives//html/Towertalk/2020-06/msg00092.html (8,347 bytes)

208. Re: [TowerTalk] Inverted Vees (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Tue, 16 Jun 2020 05:14:32 -0500
The current distribution from the feed point to ends doesn't taper linearly but halfway out it isn't close to maximum. I can't model anything here and anyway, I don't put all my trust in antenna mode
/archives//html/Towertalk/2020-06/msg00112.html (10,810 bytes)

209. Re: [TowerTalk] Inverted Vees (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Tue, 16 Jun 2020 05:36:33 -0500
<<<As Jim pointed out horizontal polarization beats vertical polarization almost all the time. Your V is H-pol. I've modeled dozens of antennas for restricted spaces (like suburban lots) and, of cour
/archives//html/Towertalk/2020-06/msg00113.html (9,035 bytes)

210. Re: [TowerTalk] Inverted Vees (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Tue, 16 Jun 2020 08:45:40 -0500
Correction: That should have read: The ends of a low inverted V are in a similar situation. _______________________________________________ _______________________________________________ TowerTalk
/archives//html/Towertalk/2020-06/msg00119.html (7,856 bytes)

211. Re: [TowerTalk] Mystery hardware part. (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Sun, 16 Aug 2020 06:41:01 -0500
Welcome to the world of modern hardware. Where you can walk into a store and fill a teeny bag of washers, angle brackets, split bolts and so on, and have $50 to $100 less in your pocket when you lea
/archives//html/Towertalk/2020-08/msg00105.html (7,855 bytes)

212. Re: [TowerTalk] Wire Rope (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Thu, 10 Sep 2020 05:06:45 -0500
I've been told that modern copperweld doesn't have anywhere near the thickness of copper on it compared to the copperweld of 60 or 70 years ago. The old wire lasted. I think W6AM used it with his rho
/archives//html/Towertalk/2020-09/msg00109.html (8,790 bytes)

213. Re: [TowerTalk] Looking for a light coaxial (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Sat, 12 Sep 2020 05:20:33 -0500
It's a fixed non-rotatable wire beam. A balanced antenna. Feed it with balanced line. Light weight ladder line in the 400 to 600 ohm range. You can use AWG 16 stranded. No baluns, significant loss, h
/archives//html/Towertalk/2020-09/msg00137.html (9,368 bytes)

214. Re: [TowerTalk] Vertical dipole other choices? (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Wed, 21 Oct 2020 04:55:28 -0500
Hi Steve, You originally expressed interest in 80 meter antennas so I'm going to address that in the context of vertical dipoles. Firstly, you left out some information that matters: How high are you
/archives//html/Towertalk/2020-10/msg00197.html (9,476 bytes)

215. Re: [TowerTalk] Vertical dipole other choices? (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Tue, 27 Oct 2020 13:56:10 -0500
By the way, I don't know if this was pointed out or not, but with a very good low loss ground system, creating a highly efficient vertical monopole, the power density is almost twice as high as that
/archives//html/Towertalk/2020-10/msg00256.html (9,009 bytes)

216. Re: [TowerTalk] Vertical dipole other choices? (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Wed, 28 Oct 2020 06:00:04 -0500
There's no mileage to vary because a receiving test is hardly any kind of accurate assessment of antenna transmitting efficiency. Put up a half wave vertical and put in a ground system of at least 6
/archives//html/Towertalk/2020-10/msg00263.html (9,853 bytes)

217. Re: [TowerTalk] Vertical dipole other choices? (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Wed, 28 Oct 2020 07:05:33 -0500
"Modeling" is hardly conclusive and you don't say how long your modeled radials were. They have to be 1/2 lamda to return the induced currents in earth from the current maxima halfway up the driven
/archives//html/Towertalk/2020-10/msg00264.html (11,625 bytes)

218. Re: [TowerTalk] Vertical dipole other choices? (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Wed, 28 Oct 2020 10:51:06 -0500
In this case reciprocity may not exist. Also, if you are measuring skywave received signals, there are variables that are not being controlled. You also compared the radialess half wave with a 90 de
/archives//html/Towertalk/2020-10/msg00268.html (10,398 bytes)

219. Re: [TowerTalk] Where to get LMR 400 (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Mon, 2 Nov 2020 13:30:30 -0600
To be honest, I've never understood the love affair with LMR. I think it's horrible cable. You have an aluminum foil shield with tinned copper braid laid over it. I wouldn't want to solder that and
/archives//html/Towertalk/2020-11/msg00011.html (8,469 bytes)

220. [TowerTalk] Adding to existing radial field (score: 1)
Author: Rob Atkinson <ranchorobbo@gmail.com>
Date: Wed, 25 Nov 2020 04:37:05 -0600
How many radials are already down? What frequencies is the antenna used for? How long are the existing radials? 73 Rob K5UJ _______________________________________________ ___________________________
/archives//html/Towertalk/2020-11/msg00222.html (6,990 bytes)

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