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101. [Amps] 10 Meters (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Thu, 14 Mar 2002 15:24:51 -0000
One difficulty with higher DC supplies is the relays that are needed to provide complete galvanic isolation without arcing. That's why the 270volt dc bus standard for new military aircraft led to the
/archives//html/Amps/2002-03/msg00306.html (8,505 bytes)

102. [Amps] 10 Meters (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Thu, 14 Mar 2002 16:02:02 -0000
Except for the EMC problems in the car electrics......... Was it not one of the Toyota 4WD vehicles that blew the computer if you used 100 watts of RF at HF in it? About 10 years ago, I guess - there
/archives//html/Amps/2002-03/msg00309.html (8,785 bytes)

103. [Amps] 10 Meters (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Fri, 15 Mar 2002 07:24:52 -0000
Showing my age now, doesn't that sound a bit like something called an SCR299? 73 Peter G3RZP
/archives//html/Amps/2002-03/msg00339.html (7,598 bytes)

104. [Amps] Plasma Generator (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Mon, 18 Mar 2002 13:08:11 -0000
I wouldn't! I've been in it for 23 years, and I really wouldn't advise it....Try something honest, like politics! 73 Peter G3RZP
/archives//html/Amps/2002-03/msg00394.html (6,409 bytes)

105. [Amps] Tuned Input ? (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Wed, 20 Mar 2002 07:42:26 -0000
It's probably worth noting that the current in them isn't negligible, so itsy bitsy little wire ended parts may not offer adequate reliability - depending on how long you take to tune up, if you use
/archives//html/Amps/2002-03/msg00435.html (7,306 bytes)

106. [Amps] Henry 2KD Classic (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Thu, 21 Mar 2002 15:31:07 -0000
I'd add to that that if you hear a ticking noise from the caps, they're history, too - and in both cases, not very good history! Sometimes they tick as they break down inside. Where are the resistors
/archives//html/Amps/2002-03/msg00464.html (7,864 bytes)

107. [Amps] Henry 2KD Classic (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Fri, 22 Mar 2002 07:19:37 -0000
I don't know whether there's a correlation between physical size and life. I have a Sprague 32 mfD 450v electrolytic, manufactured in 1944. It hadn't been used for 40 years until I checked it out las
/archives//html/Amps/2002-03/msg00497.html (7,770 bytes)

108. [AMPS] FS:ARRL-002 Hipersil Xfmr (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Mon, 4 Feb 2002 08:03:17 -0000
Don't understand. How does shorting or opening affect the resistance of the winding? The advantage of shorting the primary while measuring the secondary resistance I can see; the back EMF from discon
/archives//html/Amps/2002-02/msg00047.html (7,791 bytes)

109. [AMPS] FS:ARRL-002 Hipersil Xfmr (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Mon, 4 Feb 2002 15:10:02 -0000
I've never zapped the meter, but I have zapped me with that back emf! 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative requests: amps-R
/archives//html/Amps/2002-02/msg00050.html (7,595 bytes)

110. [AMPS] Power out indicator (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Mon, 18 Feb 2002 09:50:45 -0000
Sri for delay - been away. Generally speaking, I agree with Rich. However, some tuner circuits can be tuned up to have a very low input SWR and no output, with the tuner losses being transformed up t
/archives//html/Amps/2002-02/msg00180.html (9,156 bytes)

111. [AMPS] Power out indicator (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Mon, 18 Feb 2002 11:47:55 -0000
The tuner for the British Army D11/D13 tx's could certainly do it. I've seen it in a Z match, too. Not often - depends on the load. I don't like the Z match anyway. Especially in a Z match - which is
/archives//html/Amps/2002-02/msg00183.html (9,068 bytes)

112. [AMPS] Power out indicator (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Tue, 19 Feb 2002 07:15:34 -0000
That an input match can be achieved is not in dispute. When the input match is achieved, there should be output, and with some tuner circuits, that may not always be the case. In other words, two mat
/archives//html/Amps/2002-02/msg00194.html (9,554 bytes)

113. [AMPS] Power out indicator (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Tue, 19 Feb 2002 08:02:46 -0000
It's quite easy in a Z match, although a lot depends on what you define as a 'reasonable load'. Think about one thing: if a Z match is so good, why are so many of the commercial tuners T or L network
/archives//html/Amps/2002-02/msg00196.html (10,198 bytes)

114. [AMPS] Power out indicator (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Tue, 19 Feb 2002 13:06:39 -0000
Don't follow that one. In the L network, the Q is fixed by the impedance transformation. In the pi or the T (one of which is the dual of the other), having the three variables allows Q to be a chosen
/archives//html/Amps/2002-02/msg00199.html (8,425 bytes)

115. [AMPS] Parallel Network (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Mon, 25 Feb 2002 08:53:08 -0000
Sorry for delayed reply - been travelling, and going to be in Stcokholm quite a lot in the next two months, so reading e mails intermittently. The parallel tuned circuit tuner is very flexible: howev
/archives//html/Amps/2002-02/msg00266.html (7,827 bytes)

116. [Amps] test (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Tue, 26 Feb 2002 08:49:00 -0000
/archives//html/Amps/2002-02/msg00285.html (6,181 bytes)

117. [AMPS] Chassis for HB Amps (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Thu, 3 Jan 2002 07:27:00 -0000
It's said that if you have any skill, the only tools you need are a drill, hacksaw and file. I haven't got that skill............but having got me a guillotine (shear) and bender (brake) as well as a
/archives//html/Amps/2002-01/msg00030.html (8,162 bytes)

118. [AMPS] Building new 4-1000A amp (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Thu, 3 Jan 2002 08:58:54 -0000
I used an L network in a marine tx many years ago: the antenna load for test purposes in the 1.6 - 3.8MHz band was 10 ohms in series with 250pF, so an L network gave adequate harmonic rejection. The
/archives//html/Amps/2002-01/msg00031.html (8,266 bytes)

119. [AMPS] Building new 4-1000A amp (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Thu, 3 Jan 2002 12:37:35 -0000
For some reason (advancing age?) I forgot to mention the 'half wave filter', popular back in the early days of dealing with TVI. Being an electrical half wave, it reproduces the load impedance back a
/archives//html/Amps/2002-01/msg00033.html (8,917 bytes)

120. [AMPS] Building new 4-1000A amp (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Fri, 4 Jan 2002 13:55:48 -0000
Very true, and you need to use low loss cable, too. I did the sums for a half wave filter for 7MHz using a cable stub for the capacitor: using 1/2inch Heliax was OK on loss, but a bit too big for an
/archives//html/Amps/2002-01/msg00050.html (8,201 bytes)


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