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Total 156 documents matching your query.

61. Re: [Amps] little OT, but here goes . . . (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Sun, 22 Jun 2008 11:36:07 +0100
Loud is good, louder is better David G3UNA _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2008-06/msg00169.html (8,013 bytes)

62. Re: [Amps] Silver Strap (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Tue, 8 Jul 2008 18:49:40 +0100
I've read that silver plated coils encourage VHF and UHF oscillations. David G3UNA Silver! What a waist! After all it´s only 28 MHz. _______________________________________________ Amps mailing list
/archives//html/Amps/2008-07/msg00062.html (8,512 bytes)

63. Re: [Amps] Silver Strap (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Wed, 9 Jul 2008 06:31:13 +0100
10 marks for pretty David G3UNA _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2008-07/msg00077.html (9,496 bytes)

64. Re: [Amps] Silver Strap (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Wed, 9 Jul 2008 06:47:38 +0100
On this list a while ago. The theory was that in a wide band hf amplifier vhf /uhf oscillations/ parasitics are likely and a coil lossy at those frequencies helps to degrade their power; whereas a co
/archives//html/Amps/2008-07/msg00078.html (9,101 bytes)

65. Re: [Amps] Silver Strap (score: 1)
Author: <d.cutter@ntlworld.com>
Date: Wed, 9 Jul 2008 10:27:07 +0100
Yes, Ian, that's just where I got the notion, but I'd be happy with a conclusion somewhere, perhaps a website...yours maybe? David G3UNA -- Email sent from www.virginmedia.com/email Virus-checked usi
/archives//html/Amps/2008-07/msg00081.html (9,608 bytes)

66. Re: [Amps] More pictures... (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Thu, 10 Jul 2008 23:46:19 +0100
I was very pleased to read that you believe a way forward with a solid state design is to use off line power, ie do the insulation in the rf stage. My ignorance with this is how the extra insulation
/archives//html/Amps/2008-07/msg00100.html (9,124 bytes)

67. Re: [Amps] Wire (score: 1)
Author: <d.cutter@ntlworld.com>
Date: Tue, 29 Jul 2008 12:46:26 +0100
My *2kW* Drake balun has a polycarbonate frame around the toroid to support the bare wire off the toroid. Bare wire cools better, particularly when suspended off the toroid like this. David G3UNA --
/archives//html/Amps/2008-07/msg00349.html (9,729 bytes)

68. Re: [Amps] Damage? (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Tue, 29 Jul 2008 18:05:17 +0100
I heard police cars are subjected to 70V/m though couldn't say what the frequency range is. David G3UNA _______________________________________________ Amps mailing list Amps@contesting.com http://li
/archives//html/Amps/2008-07/msg00351.html (8,471 bytes)

69. Re: [Amps] Damage? (score: 1)
Author: <d.cutter@ntlworld.com>
Date: Mon, 28 Jul 2008 15:22:38 +0100
I've heard that police cars are tested to around 70V/m somewhere in vhf region. David G3UNA -- Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam __
/archives//html/Amps/2008-07/msg00353.html (10,331 bytes)

70. Re: [Amps] 3-500Z glitch resistor (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Tue, 16 Sep 2008 23:10:20 +0100
Glass tubes are not so easy to find: some plastics might do just as well filled with sand. David G3UNA _______________________________________________ Amps mailing list Amps@contesting.com http://lis
/archives//html/Amps/2008-09/msg00159.html (13,325 bytes)

71. Re: [Amps] 3-500Z glitch resistor (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Wed, 17 Sep 2008 07:18:16 +0100
Something I missed, thanks for the tip. I'm not a smoker and I would have to search for a Wal-Mart over here. Shame to waste a product, though, just for the packaging. David G3UNA -- Original Message
/archives//html/Amps/2008-09/msg00168.html (15,885 bytes)

72. Re: [Amps] OT: 4 square query (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Wed, 05 Nov 2008 22:49:13 -0800
In my modelling exercises with 4 squares I have found that almost anything near a 4 square will upset it and it doesn't have to be even near resonance. have a bad effect on f/b but not much on gain a
/archives//html/Amps/2008-11/msg00036.html (7,500 bytes)

73. Re: [Amps] QRO Heat management (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Mon, 10 Nov 2008 10:28:30 -0800
Not sure if the obvious it has already been stated, but a crucial point is that the cooling air must be directed in the right place and that is quite tricky. Tubes with their own ducted fans and chim
/archives//html/Amps/2008-11/msg00094.html (7,823 bytes)

74. Re: [Amps] Vacuum Relay Issues (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Mon, 01 Dec 2008 10:45:59 -0800
I've cured problems similar to this with mechanical switches by running a small dc current thro the contacts from a 12V source. It would tricky to do this with rf involved, an isolated supply for a s
/archives//html/Amps/2008-12/msg00017.html (8,594 bytes)

75. Re: [Amps] Inductor Software? (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Fri, 05 Dec 2008 00:28:09 -0800
Therefore don't use software or even a calculator or slide rule or arithmatic - use the charts in the handbooks. The difference in inductance between tube and wire in a large diameter coil is easily
/archives//html/Amps/2008-12/msg00102.html (9,103 bytes)

76. Re: [Amps] Fwd: rx noise? (score: 1)
Author: <d.cutter@ntlworld.com>
Date: Tue, 9 Dec 2008 10:32:41 +0000
Did the regulator have proper bypass in the first place or was this a problem just waiting to pop out? Capacitor-to-regulator distance is critical. I've never known a regulator go funny if it was pro
/archives//html/Amps/2008-12/msg00165.html (8,430 bytes)

77. Re: [Amps] Fwd: rx noise? (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Tue, 09 Dec 2008 15:05:02 -0800
Fascinating stuff. I couldn't find a reference to exactly what regulator is used. 7812 or variable regulator? David G3UNA _______________________________________________ Amps mailing list Amps@contes
/archives//html/Amps/2008-12/msg00184.html (11,245 bytes)

78. Re: [Amps] Fwd: rx noise? (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Tue, 09 Dec 2008 23:41:47 -0800
That makes it even more curious. The LM7812 is less susceptible to instability compared to some others and according to a NS application note does not need an output cap for stability, though I would
/archives//html/Amps/2008-12/msg00187.html (13,387 bytes)

79. Re: [Amps] bit non in vkland! (score: 1)
Author: <d.cutter@ntlworld.com>
Date: Wed, 10 Dec 2008 15:11:26 +0000
Try Farnell, they stock the 8307ANZ £7.86 8307ARZ £11.71; MAX7543JN £8.96 MAX 110 INCOMPLETE NUMBER 73 David G3UNA -- Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software
/archives//html/Amps/2008-12/msg00189.html (8,004 bytes)

80. Re: [Amps] Autotransformer (score: 1)
Author: "David Cutter" <d.cutter@ntlworld.com>
Date: Sun, 14 Dec 2008 15:19:31 -0800
General comment: I can only use my large variac if I use a switch-on delay with it. Connected directly to the mains 240V supply it would blow a 13A fuse every time. I put a large 1k resistor in serie
/archives//html/Amps/2008-12/msg00227.html (7,174 bytes)

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