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61. Re: [Amps] Dx pedition amp ??? (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Thu, 2 Dec 2004 08:21:14 -0000; snip You can get a 600W broadband amp kit from CCI. The pcb is about 6 x 4". It needs harmonic filters, but I'm sure I've seen someone refer to a switched set you can buy if you don't want to build.; /archives//html/Amps/2004-12/msg00022.html (7,363 bytes)
62. Re: [Amps] Current draw at 110 volts for SB-200 and SB-1000 (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Fri, 3 Dec 2004 08:17:50 -0000; Part of the problem is that the current the amp pulls (or tries to pull) is not like a resistive load but is taken in big gulps for a short period. The peak current is many (typ 5-10) times the 'aver; /archives//html/Amps/2004-12/msg00039.html (7,853 bytes)
63. Re: [Amps] Current draw at 110 volts for SB-200 and SB-1000 (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Fri, 3 Dec 2004 18:41:57 -0000; The high current 'gulps' I meant are the ones every line half cycle, not at syllabic rate. The line voltage your meter measures tends to reflect a cycle to cycle average, and doesn't indicate what ha; /archives//html/Amps/2004-12/msg00047.html (10,947 bytes)
64. Re: [Amps] Current draw at 110 volts for SB-200 and SB-1000 (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Fri, 3 Dec 2004 20:16:12 -0000; Yes, that's one reason why I labelled it 'imprecise'. The current flowing into the caps has to fall to zero at the crest of the sinewave, so you can argue that the peak voltage on the caps should mat; /archives//html/Amps/2004-12/msg00050.html (11,618 bytes)
65. Re: [Amps] Current draw at 110 volts for SB-200 and SB-1000 (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Fri, 3 Dec 2004 20:25:55 -0000; My snapshot does help explain why amps can be really dreadful when run from 'building yard' generators. A 'proper' alternator has dc in the field to produce a sinewave output. If the field current ho; /archives//html/Amps/2004-12/msg00051.html (14,178 bytes)
66. Re: [Amps] the dumb question of the month? (score: 1): Author: Steve Thompson <g8gsq@ic24.net>; Date: Sat, 11 Dec 2004 10:36:42 +0000; It's a simple question, but many entire books have been written trying to answer it. Basically, sweeping it without properly defining the source and load impedances is largely wasted effort, unless y; /archives//html/Amps/2004-12/msg00175.html (7,627 bytes)
67. Re: [Amps] the dumb question of the month? (score: 1): Author: Steve Thompson <g8gsq@ic24.net>; Date: Sat, 11 Dec 2004 12:30:30 +0000; Yes. Anyone who hasn't done the flux density calculations, or doesn't know what the ferrite, is should wind the power up cautiously. Steve _______________________________________________ Amps mailing; /archives//html/Amps/2004-12/msg00177.html (7,344 bytes)
68. Re: [Amps] Rm resistor (score: 1): Author: Steve Thompson <g8gsq@ic24.net>; Date: Tue, 14 Dec 2004 09:16:12 +0000; No. The resistor from the anode to ground is the only one you need. Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/lis; /archives//html/Amps/2004-12/msg00208.html (6,742 bytes)
69. Re: [Amps] Rm resistor (score: 1): Author: Steve Thompson <g8gsq@ic24.net>; Date: Tue, 14 Dec 2004 12:23:34 +0000; The question was whether a midpoint resistor was needed when tuning a PI-L network - surely it isn't whatever the amplifier configuration. Steve _______________________________________________ Amps m; /archives//html/Amps/2004-12/msg00210.html (8,118 bytes)
70. Re: [Amps] Which High Power Combiner Should I Use? (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Tue, 28 Dec 2004 18:31:09 -0000; Maybe they think you won't have a source of 100W resistors with suitably low inductance(assuming the one they supply is such). The purpose of the resistor is to absorb any difference between the two; /archives//html/Amps/2004-12/msg00368.html (9,278 bytes)
71. Re: [Amps] 8122 x 12 (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Thu, 30 Dec 2004 10:21:56 -0000; I think it doesn't matter which end is the output, and which end is the resistor - 50% of the power goes into each one. The inductances between the anodes work with the anode capacitance to work like; /archives//html/Amps/2004-12/msg00395.html (9,648 bytes)
72. Re: [Amps] High Voltage RF Transistors and Power Supply's (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Wed, 5 Jan 2005 22:46:47 -0000; I have a recollection that at least some of the parts in the family were good for flat out power, but struggled with linear operation - I think it was in connection with a 6m amp design. There might; /archives//html/Amps/2005-01/msg00063.html (8,169 bytes)
73. [Amps] Solid state amps (score: 1): Author: Steve Thompson <g8gsq@ic24.net>; Date: Fri, 7 Jan 2005 14:38:08 +0000; An article that might be of interest to any prospective builders: By Helge Granberg, published in QST dec '82 and Jan '83. 'Mosfet RF Power: An Update'. I have a poor quality photocopy which I can ma; /archives//html/Amps/2005-01/msg00095.html (6,504 bytes)
74. Re: [Amps] Solid state amps (score: 1): Author: Steve Thompson <g8gsq@ic24.net>; Date: Fri, 7 Jan 2005 17:01:53 +0000; That's an interesting amplifier (compare it with pictures of Finnfet amps) but it's not the same one as the QST article. There are no filter or control circuit designs either. 73, Steve _____________; /archives//html/Amps/2005-01/msg00098.html (7,458 bytes)
75. Re: [Amps] Solid state amps (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Sat, 8 Jan 2005 08:11:46 -0000; MRF154s are an expensive way to buy power - basically, they are 4 x MRF150 in a single package - and more than double the price of the single devices - MRF150s are 30 cents/W. The thing with a tube a; /archives//html/Amps/2005-01/msg00120.html (8,743 bytes)
76. Re: [Amps] Solid state amps (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Sat, 8 Jan 2005 08:17:44 -0000; I remember one like that which used bipolars. The MOSFET article I have describes a complete amp built into a rack mounting case. I did some searching and I think it might have come out as Motorola a; /archives//html/Amps/2005-01/msg00121.html (8,731 bytes)
77. Re: [Amps] Solid state amps (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Sun, 9 Jan 2005 20:03:04 -0000; That's the one we're looking for - anyone got an electronic copy? Thanks, Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailm; /archives//html/Amps/2005-01/msg00156.html (8,601 bytes)
78. Re: [Amps] Re: AMPS Link coupling (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Mon, 10 Jan 2005 08:37:21 -0000; Sketching it on a Smith chart, a quarter wave transmission line transformer follows a locus with a lower peak Ql. Does that count, even if it's of limited practical use? Steve _______________________; /archives//html/Amps/2005-01/msg00168.html (8,598 bytes)
79. Re: [Amps] 50 or 60 Hz, a problem? (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Tue, 11 Jan 2005 07:51:50 -0000; In amps where it matters (probably those with external anode tubes rather than Heath stuff), beware of blower ratings. The loss of pressure and airflow at 50Hz instead of 60Hz can be significant if t; /archives//html/Amps/2005-01/msg00194.html (7,961 bytes)
80. [Amps] MOSFET amp article (score: 1): Author: "Steve Thompson" <g8gsq@ic24.net>; Date: Tue, 11 Jan 2005 11:38:15 -0000; Now available at www.eltac.co.uk/amp_article/amp.htm In order to get something readable from my photocopy, I ended up scanning in greyscale and saving as .bmp, so it's a big zip file (32Mb). Sorry to; /archives//html/Amps/2005-01/msg00197.html (6,511 bytes)

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