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Total 419 documents matching your query.

41. Re: [Amps] Liquid cooling (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 26 Aug 2011 20:51:32 +0000
Bill, Yes, and that's due to the phase modulation introduced by the varying capacitances of the FETs. These things behave like varactors! Yes, as long as you actually use an AM receiver to receive th
/archives//html/Amps/2011-08/msg00197.html (14,322 bytes)

42. Re: [Amps] Transformer material weight (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 10 Sep 2011 19:41:39 +0000
Randy, The designer has some degree of freedom to trade copper for iron, and the decision will affect the performance of the transformer in the way of making it better suited for continuous high load
/archives//html/Amps/2011-09/msg00027.html (7,722 bytes)

43. Re: [Amps] Transformer material weight (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Wed, 14 Sep 2011 18:23:56 +0000
Hi Gene, I would like to take the opportunity to clear up some misconceptions. Not so. There are several factors to play with. Firstly, core materials are not all alike, and some can work at a much h
/archives//html/Amps/2011-09/msg00104.html (13,632 bytes)

44. Re: [Amps] Transformer material weight (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 16 Sep 2011 23:19:20 +0000
Hi John, A good question! I used to have that same problem, until I found the solution! ;-) Cleaning any varnish off the laminations is the first step, but you have that right. And here comes the tri
/archives//html/Amps/2011-09/msg00116.html (9,599 bytes)

45. Re: [Amps] Transformer material weight (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Wed, 21 Sep 2011 00:51:42 +0000
Hi John, Unfortunately I have no good trick for that. Just patience, and working carefully. If it counts as a trick, a thin insulation layer between winding layers can help getting nice smooth windin
/archives//html/Amps/2011-09/msg00136.html (9,529 bytes)

46. Re: [Amps] Silver plated Cu strap sources? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Wed, 07 Dec 2011 13:33:04 +0000
I recently got some surplus silver plated copper straps, entirely for free. They came from a large power generating plant, that had its whole exciter system replaced. But these strips might be a litt
/archives//html/Amps/2011-12/msg00061.html (8,039 bytes)

47. Re: [Amps] Guidelines.....toroids for tank ckts (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 26 Mar 2012 00:44:15 +0000
It might be rather lossy. The resistive permeability might be larger than the inductive one. But once the jelly is hot, eat it, it tastes good when hot. That will leave you with a high-Q donut. A ye
/archives//html/Amps/2012-03/msg00273.html (8,808 bytes)

48. Re: [Amps] Filter Capacitors (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 13 Apr 2012 02:13:28 +0000
Jim, I will go into a little more detail than Carl did! ;-) You need to decide how much ripple is acceptable, and then simply go by the definition of the units. One farad is the amount of capacitance
/archives//html/Amps/2012-04/msg00116.html (10,085 bytes)

49. Re: [Amps] Filter Capacitors (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 13 Apr 2012 18:41:19 +0000
Gerald, It's not a theory. It's the very definition of the unit "farad"! But it's "farad", not "microfarad"! A capacitor of one microfarad instead would gain one volt in one second if charged by one
/archives//html/Amps/2012-04/msg00130.html (10,112 bytes)

50. Re: [Amps] Filter Capacitors (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sun, 15 Apr 2012 18:50:36 +0000
Hi Gerald, Dwayne, It can be calculated in several ways, of course. I was just volunteering the method I prefer, because it's the simplest and most practical I have found. When I calculate the capaci
/archives//html/Amps/2012-04/msg00146.html (14,622 bytes)

51. Re: [Amps] Tubes vs. Solid State (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Tue, 01 May 2012 19:35:36 +0000
Dear all, I have been following this thread, and at some moments shuddered at what some of you opine, and assented at what others write, and several times I would almost have replied to something, to
/archives//html/Amps/2012-05/msg00021.html (16,537 bytes)

52. Re: [Amps] every db lost re Tubes vs. Solid State (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Tue, 01 May 2012 20:13:30 +0000
Much the same here. And it's a real problem, because every connector I can buy locally (Chile) is Chinese-made, and while the best of them are satisfactory, most of the rest are junk. But not always
/archives//html/Amps/2012-05/msg00026.html (10,343 bytes)

53. Re: [Amps] Tubes vs. Solid State (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Tue, 01 May 2012 20:37:15 +0000
Al, A bucket under the desk, holding some 20 liters of water. A small submersible AC powered pump in the bucket, the kind sold in home improvement stores for decorative indoor fountains. Plain half-i
/archives//html/Amps/2012-05/msg00029.html (9,596 bytes)

54. Re: [Amps] Tubes vs. Solid State (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 03 May 2012 02:34:46 +0000
Roger, and all, In fact I have been wondering about this question. The reasons I can see for commercial manufacturers not doing it this way might be both technical and commercial: - Hams are obviousl
/archives//html/Amps/2012-05/msg00097.html (26,069 bytes)

55. Re: [Amps] Tubes vs. Solid State (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 04 May 2012 02:21:48 +0000
Bob, That typically happens when your output network isn't correctly done. There is an incredible amount of equipment, including HF ham transceivers comemrcially made today, that have incorrectly imp
/archives//html/Amps/2012-05/msg00151.html (11,675 bytes)

56. Re: [Amps] Tubes vs. Solid State (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 04 May 2012 03:33:53 +0000
Jim, I don't want to engage in a war about this matter, so I won't reply to all your statements, even when I feel different than you about them. But a few things you wrote, like direct questions, nee
/archives//html/Amps/2012-05/msg00152.html (19,539 bytes)

57. Re: [Amps] Dummy Load Blues (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 15 Jun 2012 03:06:47 +0000
I built my very own Cantenna-like dummy load several years ago. The resistor is a carbon/ceramic tubular one with silvered ends, about 4cm diameter and 10cm long. It's 50 ohm, but I have no idea abou
/archives//html/Amps/2012-06/msg00123.html (9,413 bytes)

58. Re: [Amps] Dummy Load Blues (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 15 Jun 2012 21:12:32 +0000
Larry, I didn't even measure whether the raised SWR on VHF is due to series inductance, parallel capacitance, or whatever. When I made that PI circuit, I was in a hurry to test a 1kW rig I had repair
/archives//html/Amps/2012-06/msg00163.html (8,876 bytes)

59. Re: [Amps] Lines Voltage High (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 16 Jun 2012 02:29:00 +0000
Hi Glen, and all, it's funny to see how things develop differently, depending on the country! It's true that you can supply more power, and have lower loss, by applying higher voltage to the grid. Bu
/archives//html/Amps/2012-06/msg00183.html (10,571 bytes)

60. Re: [Amps] Faulty MFJ 269 (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 07 Jul 2012 18:46:15 +0000
Andy, Check the diodes in the impedance bridge. These are quite easy to fry. A quite modest discharge of static into the antenna terminal is enough to end their life as semiconductors, and turn them
/archives//html/Amps/2012-07/msg00098.html (6,898 bytes)


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