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Total 435 documents matching your query.

381. Re: [TowerTalk] Rohn GA55GD on top brace? (score: 1)
Author: TexasRF@aol.com
Date: Thu, 19 Jan 2012 08:42:03 -0500 (EST)
Hi Bryan, the only change to 55G sections over the past 30 years or so (in my recollection) is the Z brace bending radius has increased. This is most likely a change to make the Z bracing more resist
/archives//html/Towertalk/2012-01/msg00413.html (8,331 bytes)

382. Re: [TowerTalk] Mystery rotator is Ham-M Series 4, 1966 (score: 1)
Author: TexasRF@aol.com
Date: Thu, 2 Feb 2012 09:37:29 -0500 (EST)
John, if you have a 24 to 30v (not ctritical) transformer and a motor starting capacitor you can "rig" a testing circuit. Start with the brake terminals (1 and 2 IRC) and listen for a loud clunk when
/archives//html/Towertalk/2012-02/msg00014.html (8,528 bytes)

383. Re: [TowerTalk] Coax (score: 1)
Author: TexasRF@aol.com
Date: Mon, 9 Apr 2012 08:00:10 -0400 (EDT)
Hi y'all, the receive side of the coax loss is not nearly as bad as the transmit side. This is because of all the back ground noise on the HF bands. The noise from the heavens alone is on the order o
/archives//html/Towertalk/2012-04/msg00123.html (9,304 bytes)

384. Re: [TowerTalk] Coax (score: 1)
Author: TexasRF@aol.com
Date: Mon, 9 Apr 2012 09:22:14 -0400 (EDT)
Jim, the example compares 200ft of LMR400 to RG213. The stated difference is .358 dB/100ft for a total of .716 dB. That is a power ratio of 1.179 or 100w vs 117.9w. That is easily measured with a bir
/archives//html/Towertalk/2012-04/msg00126.html (12,070 bytes)

385. Re: [TowerTalk] Balun Recommendation (score: 1)
Author: TexasRF@aol.com
Date: Thu, 19 Apr 2012 07:42:23 -0400 (EDT)
Hi All, this is an observation from an innocent bystander: With constant power level, if the antenna Z increases, The voltage increases as well, right? Conservation of energy then requires the curren
/archives//html/Towertalk/2012-04/msg00346.html (11,515 bytes)

386. Re: [TowerTalk] Balun Recommendation (score: 1)
Author: TexasRF@aol.com
Date: Fri, 20 Apr 2012 08:18:20 -0400 (EDT)
Hi All, at the risk of really showing some ignorance, a question: If the choke is doing a good job and located at the feedpoint, isn't the common mode circuit quite short? Seems that the common mode
/archives//html/Towertalk/2012-04/msg00380.html (9,277 bytes)

387. Re: [TowerTalk] Balun Recommendation (score: 1)
Author: TexasRF@aol.com
Date: Fri, 20 Apr 2012 21:56:32 -0400 (EDT)
Hi Ian and others: Is common mode current the same as rf current flowing on the coax shield because it is connected to one half of the antenna? If so, no wonder the feed point is unbalanced; there ar
/archives//html/Towertalk/2012-04/msg00401.html (12,240 bytes)

388. Re: [TowerTalk] Sprockets with 2" bore needed (score: 1)
Author: TexasRF@aol.com
Date: Sat, 28 Apr 2012 23:34:36 -0400 (EDT)
Your local bearing supplier is your friend. They can furnish any available size in quick turn around. If machining is needed (unlikely with all the parts and options available) they can provide that
/archives//html/Towertalk/2012-04/msg00627.html (9,715 bytes)

389. Re: [TowerTalk] Sprockets with 2" bore needed (score: 1)
Author: TexasRF@aol.com
Date: Sat, 28 Apr 2012 23:40:29 -0400 (EDT)
Hello All, does anyone know what size conductors are needed for a 500ft cable used with a G1000SDX rotator? Yaesu simply says use #18 if over 125ft. Thanks/73, Gerald K5GW ___________________________
/archives//html/Towertalk/2012-04/msg00628.html (8,129 bytes)

390. Re: [TowerTalk] FW: Antenna spacing on mast (score: 1)
Author: TexasRF@aol.com
Date: Sat, 15 Sep 2012 08:53:11 -0400 (EDT)
Hi All, running this problem through a mast calculator program shows a wind survival of 93 mph with the following assumptions: 1.9" OD .145" wall water pipe yield strength of pipe 27ksi pipe length 4
/archives//html/Towertalk/2012-09/msg00265.html (10,936 bytes)

391. Re: [TowerTalk] US Tower HDX572 (score: 1)
Author: TexasRF@aol.com
Date: Tue, 18 Sep 2012 09:14:57 -0400 (EDT)
Hi Tom, before giving up on the existing motor, you might try to revive it. If you can rotate the motor shaft by hand, it highly likely something is wrong with the start circuit. These motors have se
/archives//html/Towertalk/2012-09/msg00348.html (9,130 bytes)

392. Re: [TowerTalk] Choice of aluminum (score: 1)
Author: TexasRF@aol.com
Date: Sat, 13 Oct 2012 18:36:45 -0400 (EDT)
Hi Rudy, 6061-T6 aluminum has a yield strength rating the same as 6063-T832 that is sold by Texas Towers and others. The 6061-T6 costs more than 6063-T832 because of the extra heating/quenching steps
/archives//html/Towertalk/2012-10/msg00176.html (9,013 bytes)

393. Re: [TowerTalk] Crank up tower bracing rubbing against cable (score: 1)
Author: TexasRF@aol.com
Date: Fri, 19 Oct 2012 14:45:37 -0400 (EDT)
Jonathan, this sounds like a recipe for disaster! 300 to 500 pounds of force is one matter; making sure you don't exceed that with a vehicle is another matter. I have seen no 500 pound fuses. Another
/archives//html/Towertalk/2012-10/msg00332.html (10,147 bytes)

394. Re: [TowerTalk] shunt feeding tower on 160 (score: 1)
Author: TexasRF@aol.com
Date: Sun, 11 Nov 2012 20:58:57 -0500 (EST)
Hi Steve, with a vswr as low as 2:1 it would be tempting to match it right in the 50 ohm feed line with a stub match. For example. starting with 37R +j0, 40 degrees down the line the impedance is 49.
/archives//html/Towertalk/2012-11/msg00083.html (9,476 bytes)

395. Re: [TowerTalk] Hi Gain Hi-Towers (score: 1)
Author: TexasRF@aol.com
Date: Wed, 19 Dec 2012 10:26:46 -0500 (EST)
Wayne, have you done a stress analysis of the stinger? You should be able to use one of the yagi stress programs to do that. If you think about it, your 44ft stinger is similar to one half of an 88ft
/archives//html/Towertalk/2012-12/msg00085.html (12,066 bytes)

396. Re: [TowerTalk] 80M Ideas (score: 1)
Author: TexasRF@aol.com
Date: Thu, 27 Dec 2012 12:21:03 -0500 (EST)
Larry, your excellent results suggest that you have already solved the "desert radial" problem! On the unworkable 80m feed problem, that is easily solved by use of a parallel tuned circuit from the b
/archives//html/Towertalk/2012-12/msg00151.html (13,848 bytes)

397. Re: [TowerTalk] 15m monster finally up - EME and Video (score: 1)
Author: TexasRF@aol.com
Date: Tue, 5 Feb 2013 11:37:03 -0500 (EST)
Hi All, the round trip time for EME signals is about 2 1/2 seconds so it is easy to determine the path. 73, Gerald K5GW eme active on 6m, 2m, 70cm, 23cm, 13cm, 9cm, 6cm and 3cm; something is constant
/archives//html/Towertalk/2013-02/msg00085.html (16,248 bytes)

398. Re: [TowerTalk] 15m monster finally up - EME and Video (score: 1)
Author: TexasRF@aol.com
Date: Tue, 5 Feb 2013 12:09:51 -0500 (EST)
Hi Tonno, very impressive results! You may not be aware of the galactic noise arriving from various sources in the heavens. The amplitude of these noise sources vary quite a bit from day to day as th
/archives//html/Towertalk/2013-02/msg00086.html (16,201 bytes)

399. Re: [TowerTalk] Fwd: 15m monster finally up - EME and Video (score: 1)
Author: TexasRF@aol.com
Date: Wed, 6 Feb 2013 10:11:02 -0500 (EST)
Hi All, eme doppler shift varies directly with frequency. Maximum at 21MHz is + 58 Hz at moon rise and -58 Hz at moon set for latitudes near the equator and virually 0 Hz at the poles The majority of
/archives//html/Towertalk/2013-02/msg00105.html (14,810 bytes)

400. Re: [TowerTalk] possible 15M EME ES5TV to K3LR QSO on April 27. (score: 1)
Author: TexasRF@aol.com
Date: Wed, 6 Feb 2013 12:46:57 -0500 (EST)
Hi Tim, I will check out the date and elevation angles on both ends. It may well be that the angles are not compatible for eme. To work, it would have to be approaching moonset for ES5TV and shortly
/archives//html/Towertalk/2013-02/msg00109.html (11,603 bytes)


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