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References: [ +from:johnf@futurenet.co.za: 121 ]

Total 121 documents matching your query.

61. [AMPS] Running a 3-500Z in the horiz. plane (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Wed, 3 Feb 1999 16:41:19 +0200; Somewhere I have an old GEC tube data book, in they specifically say that the 572B MUST NOT be operated in the horizontal plane. OK the book is very old and I suppose that things may have changed, bu; /archives//html/Amps/1999-02/msg00101.html (10,222 bytes)
62. [AMPS] 50 ohm 50 watt resistor... (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Wed, 3 Feb 1999 16:48:39 +0200; I have tried these, at 2GHz the vswr was less than 1,2:1 Interesting as they are advertised as low-inductance resistors for switch mode power supply snubbers, low inductance they certainlt are if you; /archives//html/Amps/1999-02/msg00102.html (9,645 bytes)
63. [AMPS] MFJ-259 and matching circuits (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Wed, 3 Feb 1999 16:52:22 +0200; A subtle point I think all have missed is that 50 ohms only exists in the lab!! However, both techniques will work equally well, I think if I didn't have a $100k network analyser at my disposal I wou; /archives//html/Amps/1999-02/msg00103.html (13,486 bytes)
64. [AMPS] Cantenna Dummy loads (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Wed, 3 Feb 1999 17:02:37 +0200; Water cooled dummy loads are commonly used in the broadcast transmitter scene. I once visited Marconi in Chelmsford to do some acceptance tests on a 100kW transmitter. In each bay where the transmitt; /archives//html/Amps/1999-02/msg00104.html (11,304 bytes)
65. [AMPS] Filament voltage inrush (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Sat, 6 Feb 1999 10:21:31 +0200; These should be perfect, provided you choose the right one. They are NTC thermistors, PTC are used for tv set de-gaussing coils. The NTC type resistance drops as it heats up, PTC does the opposite. J; /archives//html/Amps/1999-02/msg00205.html (8,326 bytes)
66. [AMPS] 470uF/450v caps for $2.25 (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Tue, 9 Feb 1999 16:23:25 +0200; Question: Has anybody seen any documentation on how electrolytics perform in a strong rf field? I know that as a decoupler at rf the usual power supply type is pretty "bum". What about an amplifier w; /archives//html/Amps/1999-02/msg00271.html (14,717 bytes)
67. [AMPS] 8877 ???? (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Sun, 28 Feb 1999 19:59:41 +0200; Or fit some "hold-down" straps - Hi. John ZS5JF -- To: <amps@contesting.com> -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUES; /archives//html/Amps/1999-02/msg00701.html (7,907 bytes)
68. [AMPS] Dollars per dB (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Fri, 1 Jan 1999 13:41:43 +0200; As an old ham once told me " It's not what you put up in the air that counts, it's what you put up the coax"!!!!! Happy New Year to all John ZS5JF -- From: Rich Measures <measures@vc.net> To: <amps@c; /archives//html/Amps/1999-01/msg00007.html (9,107 bytes)
69. [AMPS] Plate load charts (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Wed, 6 Jan 1999 07:16:54 +0200; Amplifier" a tank inductor with a Q of less than 400 doesn't warrant using!!!! Measured using a Marconi Q meter I found that a Q of 600 and above is practical with normal aspect coils. The position; /archives//html/Amps/1999-01/msg00077.html (11,669 bytes)
70. [AMPS] 4CX1500B (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Tue, 12 Jan 1999 19:01:11 +0200; Pin diodes are great for rf switching at the kW level. However, they have a few shortcomings due to the circuitry you need around them to make them work. The biggest problem is the rf chokes which ar; /archives//html/Amps/1999-01/msg00159.html (8,498 bytes)
71. [AMPS] Rapid Warmup Indirectly Heated Cathode Tubes (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Tue, 12 Jan 1999 18:53:01 +0200; In the broadcasting industry the use of low heater voltage for a standby transmitter is common practice. It is known as running the filament at "black-heat". Virtually all modern tv transmitters in t; /archives//html/Amps/1999-01/msg00160.html (13,817 bytes)
72. [AMPS] 100KW induction furnace (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Thu, 21 Jan 1999 18:25:22 +0200; Did it work ? John ZS5JF -- To: <amps@contesting.com> To: <amps@contesting.com> furnace at it's amps input both of a start the noticed on shunted with reason to try conductors out -- FAQ on WWW: http; /archives//html/Amps/1999-01/msg00295.html (10,383 bytes)
73. [AMPS] big or small amps, we're all hams (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Mon, 25 Jan 1999 22:53:48 +0200; Thanks John for bringing a voice of "medium road" to the discussion. I have learnt a lot from several professional rf engineers who are not hams but understand high power amplifiers and are willing t; /archives//html/Amps/1999-01/msg00386.html (13,070 bytes)
74. [AMPS] big or small amps, we're all hams (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Tue, 26 Jan 1999 19:55:51 +0200; I agree on the inaccuracies in some of the ARRL publications. The same errors are reprinted year after year without apparently anyone checking the subject matter. I am the first to admit that most, i; /archives//html/Amps/1999-01/msg00411.html (20,469 bytes)
75. [AMPS] AIL-707 spares wanted (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Tue, 26 Jan 1999 20:30:17 +0200; Can some kind ham in the San Diego area help me to find some spares for an old spectrum analyser? I have written several times to the address without any success, maybe a phone call will have the des; /archives//html/Amps/1999-01/msg00412.html (6,692 bytes)
76. [AMPS] Bandwidth (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Wed, 27 Jan 1999 22:39:37 +0200; Right on - see how the internet slowed almost to a halt on the day the Scarr report was put on the web!!! John ZS5JF -- <amps@contesting.com> To: <amps@contesting.com> circuit, 'Occupied' or reflecto; /archives//html/Amps/1999-01/msg00497.html (9,680 bytes)
77. [AMPS] RE: Down Alpha 89 (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Thu, 28 Jan 1999 19:04:06 +0200; Had a Gecko fall off the ceiling once when I was working 2m EME and caused a "helluva" bang when it fell across the high voltage capacitor bank. Certainly wakes you up!!! John ZS5JF -- To: <amps@cont; /archives//html/Amps/1999-01/msg00533.html (9,341 bytes)
78. [AMPS] ARRL and QST (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Thu, 28 Jan 1999 19:01:55 +0200; Right on Peter - I use heavy computer simulation packages today compared to the old days when every thing was done with a calculator (and a slide rule before that!!) but as you say if you don't have; /archives//html/Amps/1999-01/msg00534.html (10,430 bytes)
79. [AMPS] ARRL and QST(and CW Relevance) (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Thu, 28 Jan 1999 21:29:14 +0200; Whereas I appreciate your concern about the subject being "off-beam" I believe myself and I suspect a lot of others like to "chew the fat" from time to time and take a very dim view of someone tellin; /archives//html/Amps/1999-01/msg00544.html (9,663 bytes)
80. [AMPS] (and CW Relevance) (score: 1): Author: johnf@futurenet.co.za (John Fielding); Date: Sun, 31 Jan 1999 09:30:10 +0200; I have an acquaintance who is a marine operator, during heavy weather (which is common on our coastline) he tells me that the pitching and rolling of the ship makes using the Inmarsat system impossib; /archives//html/Amps/1999-01/msg00642.html (10,749 bytes)

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