- 261. [AMPS] New member and Drake L7 questions (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 25 Sep 2000 14:25:14 +0100
- Even if the meter has a 500mV drop at full scale, a 1N540x in parallel will make <1% difference in the reading. Go much above 500mV, and you do see a difference because the diode starts to conduct. O
- /archives//html/Amps/2000-09/msg00984.html (9,645 bytes)
- 262. [AMPS] Amp using 833A (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 25 Sep 2000 16:30:40 +0100
- Easiest of all! You seem to have swallowed the can, too :) 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.com/g3sek -- FAQ on WWW: http:/
- /archives//html/Amps/2000-09/msg00990.html (8,973 bytes)
- 263. [AMPS] New member and Drake L7 questions (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 26 Sep 2000 08:07:13 +0100
- Many "1A" meters are actually a 100uA, 1mA or 10mA movement with an internal shunt. Open the meter and snip the shunt, and you're back on track. Only partly - remember that the voltage drop at surge
- /archives//html/Amps/2000-09/msg01015.html (9,732 bytes)
- 264. SV: [AMPS] Linearizing Linears, feedback or feedforward (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 26 Sep 2000 11:16:42 +0100
- I found one about a year ago at bookfinders.com, a network of mostly small second-hand book dealers. You enter some search data - in this case, "pappenfus" (one "s") will find what you want - and it
- /archives//html/Amps/2000-09/msg01018.html (9,765 bytes)
- 265. [AMPS] SB-220 Smoke Test (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Wed, 27 Sep 2000 15:48:11 +0100
- VLF resonances are *the* main cause of parasitic oscillation in VHF/UHF power amps. They generally arise because half-wave tuned lines become open-circuits at low frequencies, so that both the input
- /archives//html/Amps/2000-09/msg01106.html (9,204 bytes)
- 266. [AMPS] SB-220 Smoke Test (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Thu, 28 Sep 2000 07:45:59 +0100
- Since I own neither of those two amplifiers, I'm only asking a question here. As you say, there are two opposing effects and you don't know "a priori" which one will win at any given frequency. What
- /archives//html/Amps/2000-09/msg01145.html (10,376 bytes)
- 267. [AMPS] Bargain basement broadband tetrode amp (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Fri, 18 Aug 2000 07:42:01 +0100
- Oh... that's what you were asking... No, that certainly doesn't work with any RF tetrode I've ever heard of. In these tetrodes, the screen is generally designed to run at about 20% of the anode volta
- /archives//html/Amps/2000-08/msg00333.html (10,670 bytes)
- 268. [AMPS] Bargain basement broadband tetrode amp (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Fri, 18 Aug 2000 20:50:51 +0100
- Too low. The plate and screen voltages are OK, but the grid bias is too negative for the recommended ZSAC of 100mA... which is *another* thing that's important for linearity. 73 from Ian G3SEK Editor
- /archives//html/Amps/2000-08/msg00362.html (9,316 bytes)
- 269. [AMPS] Testing HV Psu (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 29 Aug 2000 10:10:10 +0100
- It depends why you want to do this. If it's to check that nothing blows up if the supply is shorted, you only need to do it once or twice and it doesn't need anything fancy. For that purpose, you cou
- /archives//html/Amps/2000-08/msg00480.html (10,258 bytes)
- 270. [AMPS] Testing HV Psu (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Wed, 30 Aug 2000 08:57:32 +0100
- Steve's memory is correct, but there is also a circuit for a HV crowbar. It uses a string of thyristors to discharge the reservoir cap, and a solid-state relay to disconnect the mains from the transf
- /archives//html/Amps/2000-08/msg00541.html (9,309 bytes)
- 271. [AMPS] Testing HV Psu (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Wed, 30 Aug 2000 08:40:55 +0100
- wrote: Sure, that would be a stupid thing for a car user to do. But you have just *manufactured* a power supply, so you do exactly what car manufacturers do - a crash test. If it works OK, all it cos
- /archives//html/Amps/2000-08/msg00542.html (8,951 bytes)
- 272. [AMPS] Testing HV Psu (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Thu, 31 Aug 2000 14:06:14 +0100
- Found the direct URL: http://www.mrs.bt.co.uk/dubus/9002-7.pdf 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.com/g3sek -- FAQ on WWW: ht
- /archives//html/Amps/2000-08/msg00576.html (8,508 bytes)
- 273. [AMPS] Buy/Sell (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 6 Jun 2000 17:15:48 +0100
- Maybe it's just that the tech/sales ratio is a bit low at present. Peter 'RZP has a topic that would wake us all up... 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadC
- /archives//html/Amps/2000-06/msg00039.html (8,107 bytes)
- 274. [AMPS] Dumb directly heated cathode amp operational questions (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Wed, 7 Jun 2000 21:27:49 +0100
- This could be a 50Hz/60Hz thing - blowers perform much more poorly on 50Hz. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.com/g3sek -- F
- /archives//html/Amps/2000-06/msg00062.html (9,235 bytes)
- 275. [AMPS] s meter calibration (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 13 Jun 2000 07:45:55 +0100
- 50uV/6dB is an IARU recommendation, but it has little effect in real life. The idea of a single input level for S9 came long before modern transceivers, where there is a choice of 2, 3 or even 4 diff
- /archives//html/Amps/2000-06/msg00144.html (9,635 bytes)
- 276. [AMPS] s meter calibration (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 13 Jun 2000 20:16:53 +0100
- line in That is the kind of thing I meant by: Also it should be possible to compensate for gain variations due to switching in various preamps or attenuators, so that the S-meter indicates the signal
- /archives//html/Amps/2000-06/msg00156.html (10,244 bytes)
- 277. [AMPS] How To Design HV Glitch Protection Circuits (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Wed, 14 Jun 2000 07:54:15 +0100
- What Bob describes can easily happen with 4CX250/350 sockets, if you don't take the trouble to protect them. Eimac's advice about a series resistor in the anode supply is good, but their advice about
- /archives//html/Amps/2000-06/msg00172.html (10,871 bytes)
- 278. [AMPS] 3cx1000a7 bias (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Sun, 18 Jun 2000 23:23:42 +0100
- This question keeps coming around, and whenever Rich mentions the string of diodes, it's also the cue for me... There's a circuit on my site that is continuously adjustable and gives true constant-vo
- /archives//html/Amps/2000-06/msg00250.html (7,856 bytes)
- 279. [AMPS] 3cx1000a7 bias (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 19 Jun 2000 20:17:02 +0100
- The URL above goes directly to the part of one particular page that is relevant to the present discussion. That page is in fact the last of three, giving background technical material and partial sch
- /archives//html/Amps/2000-06/msg00259.html (8,421 bytes)
- 280. [AMPS] G3SEK Triode Board (score: 1)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Sun, 25 Jun 2000 22:33:59 +0100
- I have e-mailed Jim directly with Digi-Key part numbers and substitution suggestions, but would also appreciate feedback from anyone else on US sources for: RFP08P05 - Harris-Intersil, P-channel MOSF
- /archives//html/Amps/2000-06/msg00387.html (7,708 bytes)
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