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Total 138 documents matching your query.

41. Re: [Amps] 3rd Order IMD (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Thu, 22 Sep 2005 14:34:12 -0400
As much as I believe Hallicrafters and Johnson are well designed transmitters, I don't believe they use NFB in their finals. The equipment at my QTH is exclusively boat anchor. David KC2JD --Original
/archives//html/Amps/2005-09/msg00295.html (7,772 bytes)

42. [Amps] Advise on Oscilloscopes (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Sat, 8 Oct 2005 11:26:03 -0400
I am looking to upgrade my workbench and want to replace my oscilloscope. I want 2 channel scope that is a true dual beam with dual time bases. What are some recommendations for scopes that are not p
/archives//html/Amps/2005-10/msg00185.html (6,701 bytes)

43. Re: [Amps] arent we a little off topic here?? (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Mon, 10 Oct 2005 12:46:58 -0400
Many years ago there was a construction article for a beautiful CW transmitter in the 1967 ARRL Handbook entitled "A Self-Contained 450-Watt C.W. Transmitter". Following the details in the article, I
/archives//html/Amps/2005-10/msg00248.html (9,798 bytes)

44. [Amps] HP VTVM Parts (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Wed, 26 Oct 2005 13:25:06 -0400
Does anyone have a spare DC probe assembly or the plastic housing of the DC probe for a HP 410C VTVM? I accidentally set a hot soldering iron down on mine and semi-melted it. It still works but looks
/archives//html/Amps/2005-10/msg00600.html (6,542 bytes)

45. Re: [Amps] looking for source of Doorknob caps besides ebay (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Thu, 27 Oct 2005 11:13:09 -0400
Economy Electronics is a source of doorknob capacitors, vacuum variables, tubes, etc. Not necessarily cheap, but if you gotta have it, you've gotta have it. David KC2JD http://www.economyelectronics.
/archives//html/Amps/2005-10/msg00624.html (8,140 bytes)

46. Re: [Amps] Buyer beware! (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Sun, 30 Oct 2005 07:11:11 -0500
I've had one similar experience with a ham in KY. I asked about parts for a Butternut antenna on another reflector and got a reply from him. He stated that a ham friend of his had seen my post and to
/archives//html/Amps/2005-10/msg00683.html (10,713 bytes)

47. Re: [Amps] schematic software? (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Tue, 1 Nov 2005 17:46:07 -0500
George, Get an older version of Visio Technical. They come cheap and work fine. I bought mine at a garage sale for a couple of dollars along with a copy of AutoCAD V13. 73 David Hi all, Does anyone k
/archives//html/Amps/2005-11/msg00014.html (7,511 bytes)

48. Re: [Amps] schematic software? (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Wed, 2 Nov 2005 15:01:41 -0500
IMHO I find that ExpressSch is fine if you are working with pc boards and solid state devices, etc. but if you are including tubes and other "obsolete" devices in your schematics, it's not so useful.
/archives//html/Amps/2005-11/msg00035.html (9,011 bytes)

49. Re: [Amps] Meaning of "conduction cooled" (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Thu, 3 Nov 2005 10:49:16 -0500
The term conduction cooled refers to a series of metal ceramic tubes that were cooled by contact with a metal heat sink though a BeO ceramic block in a manner analogous to the way solid state devices
/archives//html/Amps/2005-11/msg00047.html (8,538 bytes)

50. Re: [Amps] Meaning of "conduction cooled" (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Thu, 3 Nov 2005 12:25:59 -0500
Strictly speaking, glass envelope tubes are cooled by a combination of radiation and convection with only a very slight amount of conduction cooling. The cooling of anode is by radiation and the enve
/archives//html/Amps/2005-11/msg00052.html (9,231 bytes)

51. Re: [Amps] HV checking (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Sat, 5 Nov 2005 14:17:53 -0500
Get a good HV probe and be careful. As long as you are a little nervous about doing the testing you are probably OK. It's when you don't give it a second thought that you're in trouble. I make sure t
/archives//html/Amps/2005-11/msg00066.html (8,611 bytes)

52. Re: [Amps] Aluminum alloys for panels? (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Tue, 15 Nov 2005 17:07:21 -0500
Jim, 5052 will work OK. Go to you local metal salvage yard, i.e., scrap yard and see what you can find. I have gotten some pieces of aluminum sheet at attractive prices. Don't worry about what alloy
/archives//html/Amps/2005-11/msg00192.html (8,710 bytes)

53. Re: [Amps] Anode Impedance of 4-400A (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Tue, 15 Nov 2005 17:31:33 -0500
Eric, For a parallel pair of 4-400A's, use plate voltage divided by 1.8 times the DC current. That will give you an value for impedance that is close enough for all practical purposes. David KC2JD Do
/archives//html/Amps/2005-11/msg00193.html (7,844 bytes)

54. Re: [Amps] Anode Impedance of 4-400A (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Tue, 15 Nov 2005 20:04:39 -0500
I think we are nit picking here since the original request was for an approximation of Zp. However just to keep things going, I think a multiplier of 1.55/1.6 more closely approximates class A operat
/archives//html/Amps/2005-11/msg00203.html (11,538 bytes)

55. Re: [Amps] [R-390] R-389 Sold For $3550.00 on eBay (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Mon, 21 Nov 2005 13:35:33 -0500
Tracy, Your max bid is also hidden in proxy bidding. A snipe bid that does not exceed your bid maximum will not win the auction and would have increased the winning bid price no matter when it was pl
/archives//html/Amps/2005-11/msg00406.html (8,238 bytes)

56. Re: [Amps] Air Varible (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Sun, 1 Jan 2006 12:52:29 -0500
Ron, According to my catalogs, a 154-30 is a Johnson E series, single section, 1500V - 1000pF capacitor. David KC2JD Clearwater, FL I have a Air Varible that I bought for 8877 project. It has 154-30
/archives//html/Amps/2006-01/msg00013.html (7,505 bytes)

57. Re: [Amps] spraying tank coils ? (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Tue, 24 Jan 2006 15:39:07 -0500
Go to your local auto parts store and get some clear high temp engine enamel. David KC2JD Hi, I just wound a shiny 75 meter pi-net tank coil out of 5/16 inch copper tubing. Can I spray it with someth
/archives//html/Amps/2006-01/msg00585.html (7,890 bytes)

58. Re: [Amps] AC to DC (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Mon, 30 Jan 2006 13:24:37 -0500
Sometimes knowledge from the past is forgotten. Please refer to Bill Orr's Radio Handbook. I am looking at 1970 18th Edition, page 436, DC Relay Operation. Bill states that an AC relay will operate w
/archives//html/Amps/2006-01/msg00728.html (9,830 bytes)

59. Re: [Amps] Pi vs Pi-L (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Thu, 2 Feb 2006 08:56:14 -0500
If you check in any Handbook of Chemistry and Physics, you will see that there is very little absolute difference in conductivity between copper and silver. There may be positive attributes to silver
/archives//html/Amps/2006-02/msg00021.html (10,733 bytes)

60. Re: [Amps] silver use for conductors TSPA (score: 1)
Author: "David C. Hallam" <dhallam@rapidsys.com>
Date: Thu, 2 Feb 2006 14:41:13 -0500
I stand corrected on which facility used silver for wiring. David KC2JD Correction: The production of Pu in Hanford used reactors, and a lot of radiochemistry. While it did need lots of electricity t
/archives//html/Amps/2006-02/msg00028.html (8,266 bytes)

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