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121. Re: [Amps] 4CX10,000J / Unwanted emissions (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 03 Jul 2006 14:23:28 +0100; I haven't looked up SM5BSZ's site, but the previous post mentions good IMD. I was raving about my R4C and TS830 phase noise and rx dynamic range and a friend brought in his TS50 for comparison. In a; /archives//html/Amps/2006-07/msg00092.html (8,918 bytes)
122. Re: [Amps] Advanced Power Technologies ARF1505 (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Thu, 06 Jul 2006 10:44:09 +0100; On the output perhaps. 5000pF Cin will make broadband input matching very interesting! Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contest; /archives//html/Amps/2006-07/msg00236.html (8,203 bytes)
123. Re: [Amps] Advanced Power Technologies ARF1505 (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Thu, 06 Jul 2006 13:52:14 +0100; The 5400pF is measured at 1MHz, but it's not going to change that much at other frequencies, and at the upper end of hf Zi looks like a half decent short circuit. Maybe matching at the top end and th; /archives//html/Amps/2006-07/msg00238.html (8,650 bytes)
124. Re: [Amps] Advanced Power Technologies ARF1505 (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Thu, 06 Jul 2006 15:06:26 +0100; The datasheet says +j0.6 at 27MHz - looking at the figures for 13/27/40MHz, Zi models roughly as 9nH in series with 5400pF in series with 0.3R. The inductance sounds about right for the bond wires. O; /archives//html/Amps/2006-07/msg00241.html (9,047 bytes)
125. Re: [Amps] Ferritronics FL2200m DBM for 4CX10,000amp (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Tue, 11 Jul 2006 07:30:43 +0100; Use a 47R resistor and diode probe to measure the LO level, and then map the pin connections. I'd be very surprised if Mini-Circuits didn't have something that will drop in and work fine. I've always; /archives//html/Amps/2006-07/msg00319.html (7,542 bytes)
126. Re: [Amps] TP9383/SD1460 used in 70MHz PA (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Wed, 12 Jul 2006 07:50:38 +0100; I'd expect them to work fine on 4 or 6m. As John said, the die might have been tweaked to give best ruggedness and efficiency in class C use, but that's unlikely to stop them being useable in typical; /archives//html/Amps/2006-07/msg00342.html (7,841 bytes)
127. [Amps] High frequency heater supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Thu, 13 Jul 2006 15:37:48 +0100; Does anyone know if there are problems using high frequency (say 30kHz) ac to run the heater in a valve with a cathode? For that matter, the filament in a valve without a cathode? Thanks, Steve _____; /archives//html/Amps/2006-07/msg00369.html (6,244 bytes)
128. Re: [Amps] High frequency heater supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Thu, 13 Jul 2006 16:44:02 +0100; Yes, I had thought the same - 50/60Hz sidebands low down don't hurt anyone else, 30kHz away would. Any tiny imbalance in the heater feed would do that. Just to be clear, given variations in terminolo; /archives//html/Amps/2006-07/msg00372.html (7,712 bytes)
129. Re: [Amps] High frequency heater supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Fri, 14 Jul 2006 18:38:53 +0100; I'd echo Jim (K9YC)'s comments about mechanisms. In Europe, all spurious has to be -36dBm; 80dB down at 25W and 86dB at 100W. That demands a particular mindset, and often requires linear rather than; /archives//html/Amps/2006-07/msg00381.html (8,475 bytes)
130. Re: [Amps] Switching Power Supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Fri, 14 Jul 2006 19:31:00 +0100; Not this one - but it would apply to another one in the planning. No transformer in stock, but enough bits to build a switcher - so I get to learn something too. Not quite penniless, but certainly pa; /archives//html/Amps/2006-07/msg00385.html (7,879 bytes)
131. Re: [Amps] Switching Power Supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Fri, 14 Jul 2006 22:24:04 +0100; I'm aiming for a floating supply as the current project is a tetrode running with the screen at ground potential. I initially thought about a dc supply where the switching frequency can be filtered t; /archives//html/Amps/2006-07/msg00396.html (9,977 bytes)
132. Re: [Amps] Switching Power Supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sat, 15 Jul 2006 07:48:06 +0100; For what I have in mind, the heater supply will come from the secondary of a fully isolated transformer. 5kV insulation is easy to achieve and fault current shouldn't flow through the heater. I don't; /archives//html/Amps/2006-07/msg00413.html (9,809 bytes)
133. Re: [Amps] Switching Power Supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sat, 15 Jul 2006 08:04:08 +0100; Yes - terminology used about directly and indirectly heated cathodes, heaters and filaments varies both within and across continents. Given my interest in vintage wireless, I think of 813s, 3-500s et; /archives//html/Amps/2006-07/msg00414.html (8,827 bytes)
134. Re: [Amps] Transformers (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sun, 16 Jul 2006 09:11:18 +0100; Electromag was something that just didn't lodge in my brain at university and I struggled with inductor and transformer design for ages - especially trying to compare Gauss/Oersteds/inches with Tesl; /archives//html/Amps/2006-07/msg00434.html (7,939 bytes)
135. Re: [Amps] Transformers (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sun, 16 Jul 2006 11:46:31 +0100; I can't speak for iron cores, but all the data I've been studying recently for ferrites uses SI units - Teslas and m^2 or mm^2 - there again, it's data from European or Japanese manufacturers. I gues; /archives//html/Amps/2006-07/msg00436.html (9,362 bytes)
136. Re: [Amps] Switching Power Supplies (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sun, 16 Jul 2006 23:00:15 +0100; Hi Hal. I understand all the points you make - for sure anything with semiconductors in it has to be potentially more fragile than a simple mains transformer, but I think it also depends on situation; /archives//html/Amps/2006-07/msg00454.html (12,788 bytes)
137. Re: [Amps] FW: Transformers (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 17 Jul 2006 07:35:28 +0100; I agree entirely with your definition etc. but Rich's original question said the voltage was 400V p-p - isn't that 141V rms? In that case, the power is 400W pep. 73, Steve ___________________________; /archives//html/Amps/2006-07/msg00483.html (7,686 bytes)
138. Re: [Amps] QRO membership revoked (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 17 Jul 2006 19:04:21 +0100; Call it detox, and charge folks lots of money for the experience. Tell them it's good for their soul. I helped a local club at our VHF field day a couple of weeks ago, running a station in the '100W; /archives//html/Amps/2006-07/msg00536.html (8,488 bytes)
139. [Amps] Meaurements (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Fri, 21 Jul 2006 10:33:06 +0100; A couple of measurements I made in a spare hour: Philips 330uF 400V electrolytic (about 2 yrs old). I measured without dc bias on the cap - series resistance at 2MHz is a few tenths of an ohm, rising; /archives//html/Amps/2006-07/msg00717.html (7,109 bytes)
140. Re: [Amps] 3cx3000A7 driver (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sat, 22 Jul 2006 13:48:33 +0100; Maybe because it's fairly easy to achieve and looks impressive to those who don't realise. Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.con; /archives//html/Amps/2006-07/msg00846.html (7,815 bytes)

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