- 261. [Amps] Looking for Opinions (score: 1)
- Author: 2@vc.net (2)
- Date: Tue, 27 Aug 2002 08:26:38 -0700
- ** AEA found they had a high return rate on the LA-30. Since the returned units exhibited the symptoms of intermittent VHF instability described in the October, 1988 _QST_. they began retrofitting l
- /archives//html/Amps/2002-08/msg00284.html (7,180 bytes)
- 262. [Amps] Parasitics and Amp Supply LK-500 (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 28 Aug 2002 10:02:34 -0700
- If you have a dipmeter, check the dip between the Tune-C and the blocking C. The VHF dip in a stock LK should be sharp, indicating a high VHF-Q. This is hardly good news unless one is trying to build
- /archives//html/Amps/2002-08/msg00302.html (8,148 bytes)
- 263. [Amps] Parasitics and Amp Supply LK-500 (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 28 Aug 2002 10:09:40 -0700
- Thanks, Chris. Are aunt Emma and uncle Joe enjoying their trip to Ireland? - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures. end
- /archives//html/Amps/2002-08/msg00303.html (8,258 bytes)
- 264. [Amps] Which 3-500Z (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 28 Aug 2002 10:22:53 -0700
- RR. Another problem is the bleeder resistors produce too much heat for the electrolytics. Changing from 25-kohmequalizers to c. 100kohm would help. I still get full suds from an Amperex bottle that
- /archives//html/Amps/2002-08/msg00304.html (8,933 bytes)
- 265. [Amps] Which 3-500Z (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 28 Aug 2002 15:06:30 -0700
- The voltage on 1kd-5 and 2kd-5 filaments would be c. 5v in Singapore where they have 100v/200v, 50Hz.. As understand it, both amps were mfg in Singapore. - R. L. Measures, a.k.a. Rich..., 805.386.373
- /archives//html/Amps/2002-08/msg00312.html (7,381 bytes)
- 266. Hetaer volts, was RE: [Amps] Which 3-500Z (score: 1)
- Author: 2@vc.net (2)
- Date: Thu, 29 Aug 2002 04:55:52 -0700
- Maybe Singapore is now in step with most of the planet. Is it 60Hz? - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures. end
- /archives//html/Amps/2002-08/msg00322.html (8,803 bytes)
- 267. Heater volts, was RE: [Amps] Which 3-500Z (score: 1)
- Author: 2@vc.net (2)
- Date: Thu, 29 Aug 2002 05:44:54 -0700
- 100V-200V/50Hz motors and transformers run ok as is on 120V-240V/60Hz and vice-versa. However, 234V/50Hz units would require a special design in order to be interchangeable with 240V/60Hz. - I like
- /archives//html/Amps/2002-08/msg00325.html (10,948 bytes)
- 268. [Amps] bypass caps. (score: 1)
- Author: 2@vc.net (2)
- Date: Thu, 29 Aug 2002 05:51:18 -0700
- Ceramic [ barium-titanate ] dielectric caps have less inductance than mica-dielectric caps and they are able to carry more current instead of less above 5MHz. Ceramic caps are also less costly to ma
- /archives//html/Amps/2002-08/msg00326.html (6,730 bytes)
- 269. [Amps] al80a (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 31 Jul 2002 19:08:43 -0700
- Zero grid-fil resistrance incicates a bent filanment helix touching the grid. (Photo in September, 1990 *QST*, and on my Web site) Either the amplifier has been operated aeronautical mobile in an ac
- /archives//html/Amps/2002-07/msg00004.html (7,464 bytes)
- 270. [Amps] RE: FW: diode strings...bias (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 31 Jul 2002 19:08:46 -0700
- ** If 600pF of grid bypass to gnd was causing the drive requirement to go up, there should have been a difference between 3.5 and 29MHz. At 3.5MHz, 600pF has 75-ohms. At 29MHz, 9.5-ohms. ** the 922
- /archives//html/Amps/2002-07/msg00005.html (10,015 bytes)
- 271. [Amps] SB-200 power supply (score: 1)
- Author: 2@vc.net (2)
- Date: Tue, 16 Jul 2002 16:38:59 -0700
- 1n5408s typically measure >1100piv. The cost should be under 19¢ each. - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures. end
- /archives//html/Amps/2002-07/msg00232.html (7,056 bytes)
- 272. [Amps] KW Linear for FT-817 (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 02:47:40 -0700
- A power-gain of x300 from one tetrode or pentode is not any easy trick. The most I ever managed to do was x100. The potential trouble with designing in more gain is that a higher grid-terminating res
- /archives//html/Amps/2002-07/msg00240.html (7,610 bytes)
- 273. [Amps] KW Linear for FT-817 (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 07:42:46 -0700
- ** A 1500W-out transistor HF linear amplifier produces c. 1600w-max of heat. A heat sink to remove this amount of heat is somewhat :) larger than 11" x 7" x 4". cheers, Alex - R. L. Measures, a.k.a.
- /archives//html/Amps/2002-07/msg00247.html (8,695 bytes)
- 274. [Amps] Bias Zener Diodes In Parallel ? (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 09:52:21 -0700
- Does P equal I^2*R, Tom? I thought P equals E*I = 4.48w. 5W zeners are in DO5 packages, which are like axial-lead 3A rectifiers, which don't use a heat sink. Zener case temp is 25ºC/77ºF-m
- /archives//html/Amps/2002-07/msg00257.html (10,068 bytes)
- 275. [Amps] KW Linear for FT-817 (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 09:52:26 -0700
- ** This issue had nothing to do with what the gentleman asked. It has to with what Alex proposed as a solution. cheerz, Alex - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measur
- /archives//html/Amps/2002-07/msg00258.html (10,298 bytes)
- 276. [Amps] Re: KW Linear for FT-817 (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 09:52:30 -0700
- Stuffing 1500W Chebyshev bandpass filters in that size box might require a 10-ton hydraulic press. cheers, Jim - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures. end
- /archives//html/Amps/2002-07/msg00259.html (7,930 bytes)
- 277. [Amps] Re: KW Linear for FT-817 (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 09:55:20 -0700
- True, but 1500W is ideal for driving an 8160. - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures. end
- /archives//html/Amps/2002-07/msg00260.html (8,249 bytes)
- 278. [Amps] Nice big Plate transformer fs (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 10:02:59 -0700
- Holy cow, that is a BIG one. The most I ever saw was 1000kv-rms @ 1A. 4620kv-rms should make c. 12 Megavolts DC in a FWD. - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures.
- /archives//html/Amps/2002-07/msg00261.html (7,716 bytes)
- 279. [Amps] Bias Zener Diodes In Parallel ? (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 13:29:24 -0700
- -- Bingo. Tom sez P=I^2*E. [see above quote] -- i.e., can both formulas be true? Does 4.48w = 3.6w? ok Good points Would the case temp of said zener be nmt 25ºC at 4.48W diss. in July? Cheers,
- /archives//html/Amps/2002-07/msg00265.html (10,461 bytes)
- 280. [Amps] Bias Zener Diodes In Parallel ? (score: 1)
- Author: 2@vc.net (2)
- Date: Wed, 17 Jul 2002 16:54:25 -0700
- I have never seen anything smaller than 10w in a stud mount. 3A axial lead rectifiers are in a DO-5 case. - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures. end
- /archives//html/Amps/2002-07/msg00272.html (9,257 bytes)
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