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361. Re: [TenTec] Antenna measurements (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Tue, 23 Apr 2013 22:07:01 +0100; This is the concise statement I have in my (very) old course notebook: Static charge -> electric field Moving charge (non-accelerating) -> magnetic field Accelerating or decelerating charge -> EM rad; /archives//html/TenTec/2013-04/msg00255.html (11,713 bytes)
362. Re: [TenTec] Built in SWR meter bannans (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Wed, 24 Apr 2013 09:18:55 +0100; Rick, It's not difficult - just a bit tedious - to work this stuff out. Let me walk you through the example of a feedpoint 1:1 balun for a 40m beam: 1) Assume the power level is 1kW and the beam feed; /archives//html/TenTec/2013-04/msg00281.html (13,391 bytes)
363. Re: [TenTec] Built in SWR meter bannans (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Wed, 24 Apr 2013 11:54:38 +0100; That's correct! So if I were a tuner manufacturer I might be tempted to use an iron powder core for the balun rather than a "lossy" mix like #31 or #43 - the customer probably wont spot that it achie; /archives//html/TenTec/2013-04/msg00285.html (10,757 bytes)
364. Re: [TenTec] Built in SWR meter bannans (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Wed, 24 Apr 2013 20:54:08 +0100; Certainly Sevick's books are some of the very few available on the topic, but I'm not sure I would call them "definitive works". I know that may appear to be heresy, but I've now "invested" in 3 of S; /archives//html/TenTec/2013-04/msg00304.html (11,045 bytes)
365. Re: [TenTec] Built in SWR meter bannans (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Wed, 24 Apr 2013 22:42:18 +0100; If you wind a 4:1 Guanella balun as two identical 1:1 chokes on a common core, you force the CM voltages across the two chokes to be the same because they share the same flux. If we call the input vo; /archives//html/TenTec/2013-04/msg00311.html (12,329 bytes)
366. Re: [TenTec] 9420 PS Problem (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Sun, 09 Jun 2013 15:35:20 +0100; Mine failed 9 years ago and I fitted a Ł15 replacement from RS-Components here in UK. Not much help to you as the part is no longer available :( It's worth noting that transformer is powered 24x7x365; /archives//html/TenTec/2013-06/msg00051.html (7,795 bytes)
367. [TenTec] 961 Power supply - internal photos needed (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Sat, 06 Jul 2013 15:34:49 +0100; I have most of the pieces to replicate a 961 Power Supply to go with my spare CorsairII, but I don't have the 81402 Pass Transistor board. The components for the board are easy to source, but I just; /archives//html/TenTec/2013-07/msg00111.html (7,436 bytes)
368. Re: [TenTec] Tuner (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 08 Jul 2013 21:21:04 +0100; For the record, here's a Smith Chart that shows in the coloured areas those impedances which need the so-called "HighZ" L-match configuration: http://www.karinya.net/g3txq/temp/hiz_loz.png In the Gre; /archives//html/TenTec/2013-07/msg00124.html (8,792 bytes)
369. Re: [TenTec] Tuner (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 08 Jul 2013 22:56:01 +0100; At 3.5MHz, the SWR(50) of an 80m dipole cut for resonance at 3.8MHz could easily be 12:1 or higher. Depending on the length of the coax, that can present impedances at the tuner that will be well out; /archives//html/TenTec/2013-07/msg00130.html (8,863 bytes)
370. Re: [TenTec] Tuner (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 08 Jul 2013 23:21:30 +0100; The problem is most acute when the length of the coax transforms the off-resonance feedpoint impedance to a low resistive value - for example around 6 Ohms for 45ft of Rg-8X; the tuner then doesn't h; /archives//html/TenTec/2013-07/msg00132.html (9,884 bytes)
371. Re: [TenTec] Tuner (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Tue, 09 Jul 2013 11:17:58 +0100; Let's not perpetuate the myth that the G5RV was designed as a single band 20m antenna! "Since only an average size back garden was available it was not deemed worthwhile to construct a beam for the D; /archives//html/TenTec/2013-07/msg00151.html (10,386 bytes)
372. Re: [TenTec] OCF antennas evolution (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Thu, 11 Jul 2013 21:52:18 +0100; Because: a) It's a voltage balun and therefore will drive *unequal* currents into anything except a perfectly balanced load. A voltage balun has *zero* common-mode impedance. b) Its a 4:1 balun; so,; /archives//html/TenTec/2013-07/msg00264.html (10,148 bytes)
373. Re: [TenTec] OCF antennas evolution (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Sat, 13 Jul 2013 17:06:49 +0100; I would expect the current "hot spots" to be every 22ft or so on 15m. You should slide the current probe at least 11ft to be sure to encompass one. Perhaps that's what you meant? Steve G3TXQ On 12/07; /archives//html/TenTec/2013-07/msg00305.html (11,396 bytes)
374. Re: [TenTec] TT 238C will not tune (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 29 Jul 2013 10:06:25 +0100; A number of points: 1) An "ugly" balun is a poor choice for use at the output of a wide-band tuner. It has high choking impedance over only a very narrow band of frequencies, and outside that narrow; /archives//html/TenTec/2013-07/msg00434.html (11,958 bytes)
375. Re: [TenTec] OT: Openwire/Window Line and Bad Wx (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Mon, 29 Jul 2013 19:22:21 +0100; ARRL literature has consistently underestimated the losses of ladderline. For example, the matched losses quoted in the ARRL Antenna Book - at least up to the 21st edition - are about one half the fi; /archives//html/TenTec/2013-07/msg00449.html (12,011 bytes)
376. Re: [TenTec] OT: Openwire/Window Line and Bad Wx (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Wed, 31 Jul 2013 22:07:08 +0100; I found time today to do some experimenting on this issue of how window-line losses increase when the line gets wet. I took 60ft of 300 Ohm window (JSC 20AWG conductors) and suspended it about 4ft ab; /archives//html/TenTec/2013-07/msg00489.html (10,817 bytes)
377. Re: [TenTec] OT: Openwire/Window Line and Bad Wx (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Thu, 01 Aug 2013 14:41:02 +0100; I've now run this experiment a further 3 times with pretty consistent results: on average, adding the water dropped the velocity factor by 1.8% and increased the matched loss by 0.25db/100ft at 26MHz; /archives//html/TenTec/2013-08/msg00003.html (9,108 bytes)
378. Re: [TenTec] OT: Openwire/Window Line and Bad Wx (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Thu, 01 Aug 2013 16:19:10 +0100; Problem solved .... I think. Just added some wetting agent - washing up liquid - to the water and re-sprayed. Losses jumped to 5dB/100ft at 26MHz! Steve G3TXQ I hope you document the test on your web; /archives//html/TenTec/2013-08/msg00011.html (9,768 bytes)
379. Re: [TenTec] OT: Openwire/Window Line and Bad Wx (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Thu, 01 Aug 2013 19:26:33 +0100; Ok, let me try the simple Executive summary: Taking a length of window-line fresh off the drum, and dowsing it with UK (midlands) rain water I see an small increase in attenuation at the top of the H; /archives//html/TenTec/2013-08/msg00023.html (11,234 bytes)
380. Re: [TenTec] OT: Openwire/Window Line and Bad Wx (score: 1): Author: Steve Hunt <steve@karinya.net>; Date: Sat, 03 Aug 2013 14:01:40 +0100; We're talking here about reported changes in loss that - if true - would be equivalent to a 5dB change between dry and wet on a 100ft of ladderline feeding a doublet on 10m. Are you folks trying to t; /archives//html/TenTec/2013-08/msg00041.html (12,588 bytes)

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