Mail Archive Search: <+from:g3rzp@g3rzp.wanadoo.co.uk>

Results:

References: [ +from:g3rzp@g3rzp.wanadoo.co.uk: 523 ]

Total 523 documents matching your query.

181. Re: [Amps] Mica cap substitute \ alternative (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Wed, 12 Jul 2006 11:13:30 +0200 (CEST); whose current carrying ability increases from 5MHz to 30MHz, mica dielectric caps' current carrying ability decreases above 5MHz.< Yes, but WHY? What's the mechanism that allows mica to be a perfectl; /archives//html/Amps/2006-07/msg00343.html (7,708 bytes)
182. Re: [Amps] Mica cap substitute \ alternative (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Thu, 13 Jul 2006 12:42:56 +0200 (CEST); So we are told that some manufacturers derate some mica caps above 5MHz. Others have caps that in slightly different applications have ratings that are high. Some mica caps can handle high currents i; /archives//html/Amps/2006-07/msg00361.html (8,404 bytes)
183. Re: [Amps] Mica cap substitute \ alternative (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Fri, 14 Jul 2006 11:03:04 +0200 (CEST); mica at all. It could well be due to heating in the very thin metallization, which would increase with frequency due to the skin effect.< Wouldn't one get the same effect with ceramic caps, where the; /archives//html/Amps/2006-07/msg00378.html (8,711 bytes)
184. Re: [Amps] Filament life (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Sat, 15 Jul 2006 16:20:05 +0200 (CEST); Bearing in mind the effects of metal migration, do you get as good a filament life on DC as on AC? I know the old dull emitter filament valves were quite good, but there's a lot of difference in meta; /archives//html/Amps/2006-07/msg00419.html (6,854 bytes)
185. Re: [Amps] Transformers (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Sun, 16 Jul 2006 09:07:08 +0200 (CEST); core size from the output power in watts it needs to deliver.< A 'reductio ad absurdum' suggests that if core size and saturation doesn't matter, there's no need for those big 1MW+ transformers that; /archives//html/Amps/2006-07/msg00430.html (7,564 bytes)
186. Re: [Amps] transformers (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Mon, 17 Jul 2006 10:53:54 +0200 (CEST); common ways to read power. First, scopes have passband ripple. They are designed of good response to a stepped waveform, frequency response flatness (or lack of ripple) is secondary. Second, they are; /archives//html/Amps/2006-07/msg00484.html (8,747 bytes)
187. [Amps] RF Chokes (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Mon, 17 Jul 2006 11:23:41 +0200 (CEST); So what inductance should the shunt feed RF Choke be? Take a 'classic' choke - the old National R-175, used at the kW DC input in AM days. It's 145 microhenries, so with something around 2kV rms acro; /archives//html/Amps/2006-07/msg00485.html (8,761 bytes)
188. Re: [Amps] FW: Transformers (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Mon, 17 Jul 2006 13:15:41 +0200 (CEST); Happens to be the ITU definition - since 'way back when'. 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/lis; /archives//html/Amps/2006-07/msg00495.html (6,979 bytes)
189. Re: [Amps] RF Chokes (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Mon, 17 Jul 2006 13:27:26 +0200 (CEST); at 90 degrees to one another , if I recall the physical layout correctly) with one fixed and one switchable bypass capacitor< Again, a situation where, especially at the LF end of the band, there's a; /archives//html/Amps/2006-07/msg00497.html (7,421 bytes)
190. Re: [Amps] transformers (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Mon, 17 Jul 2006 13:41:28 +0200 (CEST); accurate meters.< Accurate RF power measurement isn't quite as easy as it may sometimes appear. So much so that for European Standards, a measurement uncertainty of +/-0.75dB is allowed. That does i; /archives//html/Amps/2006-07/msg00499.html (9,195 bytes)
191. Re: [Amps] RF Chokes (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Mon, 17 Jul 2006 19:25:11 +0200 (CEST); alone' and are usually referenced at a much lower frequency than Fo.< I figure that when you get down to 3.5MHz that probably isn't the case. I'm a bit tied up for the next week or so, but when I hav; /archives//html/Amps/2006-07/msg00527.html (8,042 bytes)
192. Re: [Amps] QRO membership revoked (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Mon, 17 Jul 2006 19:27:45 +0200 (CEST); meal for days.< Maybe a good dose of QRO is needed. If good enough, it could be like the difficulty with a good Italian dinner - 5 days later, you feel hungry! 73 Peter G3RZP I just spent four days o; /archives//html/Amps/2006-07/msg00528.html (8,596 bytes)
193. Re: [Amps] QRO membership revoked (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Fri, 21 Jul 2006 11:23:38 +0200 (CEST); There is a down side to long term HF QRO exposure. My father in law worked at HF tx stations running many hundreds of kW in total. A photo of him is extant, showing him on night duty, asleep in a cha; /archives//html/Amps/2006-07/msg00716.html (8,668 bytes)
194. Re: [Amps] grid fuses (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Fri, 21 Jul 2006 11:59:13 +0200 (CEST); I was always taught that to leave an electrode floating (which is what the grid is doing after the fuse blows) is bad practcie and can lead to tube damage. 73 Peter G3RZP ____________________________; /archives//html/Amps/2006-07/msg00719.html (8,207 bytes)
195. Re: [Amps]Grid fuses (was: Life and gain of 3-500Z) (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Fri, 21 Jul 2006 12:08:43 +0200 (CEST); Another point to remember about using resistors as fuses is that unless the manufacturer guarantees the fusing current, time and prospective fault voltage, you haven't a clue if the results are repea; /archives//html/Amps/2006-07/msg00720.html (7,884 bytes)
196. Re: [Amps]Grid fuses (was: Life and gain of 3-500Z) (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Fri, 21 Jul 2006 12:20:37 +0200 (CEST); So if it doesn't matter, why do tube manufacturers specify a maximum grid - cathode resistance for a lot of tubes? Even low power audio tubes used in Class A? My experience is that exceeding the the; /archives//html/Amps/2006-07/msg00722.html (7,480 bytes)
197. Re: [Amps]Grid fuses (was: Life and gain of 3-500Z) (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Fri, 21 Jul 2006 19:11:18 +0200 (CEST); We have a number of possible scenarios: 1. We get, for some reason, an arc from plate to grid. The resistor/fuse/what have you opens. Because once the arc is struck, it's a low impedance with around; /archives//html/Amps/2006-07/msg00780.html (10,252 bytes)
198. Re: [Amps]Grid fuses (was: =?ISO-8859-1?Q?Life?= and gain of 3-500Z) (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Sat, 22 Jul 2006 00:07:39 +0200 (CEST); was in scenario #1. After grid is disconnected from ground, wouldn't the arc be discharging the grid plate capacity?< I suppose so - at the same time, it's charging the grid cathode capacity. 73 Pete; /archives//html/Amps/2006-07/msg00810.html (7,272 bytes)
199. Re: [Amps] 3cx3000A7 driver (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Sat, 22 Jul 2006 13:00:16 +0200 (CEST); I'd love to know why they think a +40dBm third order intercept is worth having. In a 3kHz bandwidth, you'd need phase noise at around -160dBc/Hz to make full use of that intercept point. 73 Peter G3R; /archives//html/Amps/2006-07/msg00844.html (8,058 bytes)
200. Re: [Amps] 3cx3000A7 driver (score: 1): Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>; Date: Sun, 23 Jul 2006 09:14:59 +0200 (CEST); In tomorrow's world -160dB(c) per cycle may actually be a force to contend with......< It may be, although I have severe doubts about the technology needed. This is because, in the final analysis, lo; /archives//html/Amps/2006-07/msg00916.html (9,392 bytes)

Current List: 181 - 200
Page: [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20]