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281. Re: [Amps] 4CX1500B cathode Connection (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Mon, 23 Feb 2009 17:19:30 +0000; There's a complete data sheet online at http://www.g8wrb.org/data/Eimac/4CX1500B.pdf The download will be quite slow, as this is hosted on a home computer now. I used to have complimentary hosting fo; /archives//html/Amps/2009-02/msg00661.html (7,862 bytes)
282. [Amps] Donations wanted for http://www.g8wrb.org/ (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Fri, 15 May 2009 09:45:19 +0100; Many of you have no doubt made use of http://www.g8wrb.org/ for data sheets on tubes, information on the YC156 or whatever else you found interesting. Due to the space and bandwidth requirements, thi; /archives//html/Amps/2009-05/msg00067.html (7,460 bytes)
283. Re: [Amps] [Moon-net] Major breakthrough with regenerative yagi. (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Tue, 19 May 2009 10:33:16 +0100; It may have been sent as a joke, but perhaps it was not. Both myself and Leif (SM5BSZ) gave it some attention. Perhaps we were both fooled, but perhaps you are mistaken too. I've come across a lot of; /archives//html/Amps/2009-05/msg00118.html (8,778 bytes)
284. Re: [Amps] [Moon-net] Major breakthrough with regenerative yagi. (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Wed, 20 May 2009 07:26:01 +0100; We have the same problem here in the England - you may have seen it hit the news in the USA, as numerous things have been leaked by the Daily Telegraph. Basically our MPs have been having a great tim; /archives//html/Amps/2009-05/msg00132.html (11,794 bytes)
285. Re: [Amps] [Moon-net] Major breakthrough with regenerative yagi. (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Wed, 20 May 2009 07:41:20 +0100; Interesting you say that. I wonder how many other kids have had the same idea. It is probably the easiest concept of a perpetual motion machine to understand. I can't think of an easier example mysel; /archives//html/Amps/2009-05/msg00133.html (10,520 bytes)
286. Re: [Amps] Query about capacitor value (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Tue, 15 Sep 2009 14:19:36 +0100; Ultimately, it it worth what someone is willing to pay for it. Stick it on eBay and see what it fetches. Not knowing its specs is likely to devalue it quite a bit. It's probably not too useful as a 5; /archives//html/Amps/2009-09/msg00195.html (8,049 bytes)
287. Re: [Amps] Eimac tube on the 'bay (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Wed, 28 Oct 2009 22:47:53 +0000; I can't say for the USA, but I have it in my house. The reason it was installed was the load of 27 'economy 7' storage heaters. The heaters were distributed around the 3 phases. If you said you inten; /archives//html/Amps/2009-10/msg00346.html (9,547 bytes)
288. Re: [Amps] Stripline design (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Thu, 19 Nov 2009 23:13:28 +0000; The theory and the practice do not always agree too much, but some of the RSGB and ARRL manuals do cover the theory Basically you need to make a transmission which has an equal and opposite reactance; /archives//html/Amps/2009-11/msg00204.html (11,126 bytes)
289. Re: [Amps] Stripline design (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Fri, 20 Nov 2009 00:37:50 +0000; I think the original poster wanted an understanding of stripline design - something you do not get by plugging in dimensions into expensive closed-source 'black-box' software. The theory of transmiss; /archives//html/Amps/2009-11/msg00206.html (14,193 bytes)
290. Re: [Amps] Dummy Loads & Wattmeters (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Wed, 02 Dec 2009 18:21:47 +0000; There is no such thing as an accurate power measurement with a Bird 43. As an 'industrial placement' during an electrical and electronic engineering degree, I worked in a National Standards Laborator; /archives//html/Amps/2009-12/msg00040.html (10,281 bytes)
291. Re: [Amps] power meters for HF/VHF (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Thu, 03 Dec 2009 00:10:18 +0000; I would argue you need to do this if you want better than 10-15%, not 5%. Also remember the Bird is (or at at least was) rated at +/- 5% of FSD. So if you are measuring at the half scale, Bird would; /archives//html/Amps/2009-12/msg00052.html (11,098 bytes)
292. Re: [Amps] Dummy Loads & Wattmeters (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Thu, 03 Dec 2009 00:21:41 +0000; I've no idea personally. I just know a Bird slug in a Bird 43 is not as good as Bird make it out to be. Dave _______________________________________________ Amps mailing list Amps@contesting.com http; /archives//html/Amps/2009-12/msg00053.html (8,982 bytes)
293. Re: [Amps] Dummy Loads & Wattmeters (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Thu, 03 Dec 2009 21:22:30 +0000; "I can't really think why a ham needs to know RF power very accurately. In which case, Bird 43's are fine." I am saying if you want better accuracy, then there are other options. I was sharing some r; /archives//html/Amps/2009-12/msg00089.html (14,649 bytes)
294. Re: [Amps] Dummy Loads & Wattmeters (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Thu, 03 Dec 2009 21:46:11 +0000; Be aware, RMS power is a useless unit. You can compute the RMS power of an RF signal, but it is no practical use whatsoever. Dave _______________________________________________ Amps mailing list Amp; /archives//html/Amps/2009-12/msg00090.html (8,604 bytes)
295. Re: [Amps] Dummy Loads & Wattmeters (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Thu, 03 Dec 2009 22:15:10 +0000; Technically you would need to define confidence. Is being 10% certain the result is within +/- 10% OK for you? Do you need to be 50% confident it is within 10%? Do you need to be 90% confident it is; /archives//html/Amps/2009-12/msg00094.html (12,527 bytes)
296. Re: [Amps] Dummy Loads & Wattmeters (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Thu, 03 Dec 2009 22:29:09 +0000; Bird might well have calorimeters, but I very doubt they would use them routinely for calibrating meters. I suspect they use a Marconi/HP/Agilent/Boonton power meter and attenuator to routinely do it; /archives//html/Amps/2009-12/msg00096.html (9,223 bytes)
297. Re: [Amps] Electricity costs (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Wed, 09 Dec 2009 01:24:28 +0000; An ex work colleague of mine told me it often possible to get some electricity free, by using the voltage between earth and neutral. These are tied together at the local sub-station, but at your hous; /archives//html/Amps/2009-12/msg00239.html (7,966 bytes)
298. Re: [Amps] Isolation Transformer (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Mon, 14 Dec 2009 06:54:50 +0000; Virtually all transformers sold today are isolation transformers, in that they do provide isolation between primary and secondary. An 'auto-transformer' does not, but they are quite rare beasts. So f; /archives//html/Amps/2009-12/msg00316.html (8,662 bytes)
299. Re: [Amps] water cooling (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Sun, 20 Dec 2009 14:48:06 +0000; Perhaps I have mis-understood what you are saying, in which case I apologise. Surely it is conductivity of the water that matters, not of the tubing. Most plastics have a hell of a lot lower conducti; /archives//html/Amps/2009-12/msg00509.html (8,764 bytes)
300. Re: [Amps] Watts to DBM?? (score: 1): Author: "Dr. David Kirkby" <david.kirkby@onetel.net>; Date: Sun, 20 Dec 2009 15:29:42 +0000; Han, you seem to be the only one to answer the original question directly. I would have added however that the log needs to be to the base 10, and not base e. Depending on what software you use to do; /archives//html/Amps/2009-12/msg00510.html (8,088 bytes)

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