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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*\[Amps\]\s+RF\s+insulating\s+materials\s+\-\s+engineered\s+plastics\s*$/: 9 ]

Total 9 documents matching your query.

1. [Amps] RF insulating materials - engineered plastics (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Tue, 28 Aug 2012 00:40:48 -0600
I just finished a series of comparison tests of a handful of polymeric materials and blends, for use in high power VHF amplifier projects. I didn't test Nylon, Delrin acetal, Polyethylene or Polyprop
/archives//html/Amps/2012-08/msg00496.html (9,212 bytes)

2. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: David Kirkby <david.kirkby@onetel.net>
Date: Tue, 28 Aug 2012 08:48:36 +0100
An interesting set of results. Is there a zero missing on the row "PTFE+Glass 84 98 20 205 goodmechanical" since it simplies the current started at 20 mA and rose to 205 mA, when I expect you mean 20
/archives//html/Amps/2012-08/msg00497.html (9,267 bytes)

3. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Tue, 28 Aug 2012 07:51:20 -0600
John, This is extremely interesting but something seems incorrect. Assuming your teflon dielectric puck: C(pf) = .2248 * K * A * (N-1) / d = .2248 * 2.1 * PI * (1.5^2) * 1 / .75 = 4.45pF Xc @ 90MHz =
/archives//html/Amps/2012-08/msg00499.html (10,660 bytes)

4. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: "Jeff DePolo" <jd0@broadsci.com>
Date: Tue, 28 Aug 2012 11:18:02 -0400
Minor correction - you used diameter of the puck instead of the radius when calculating the area. C = 2.1 * 0.2248 * (1.5/2)^2 * pi / 0.75 = 1.11 pF Xc = 1593 I = 10607/1593 = 6.66 Arms -- Jeff WN3A
/archives//html/Amps/2012-08/msg00502.html (13,293 bytes)

5. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Tue, 28 Aug 2012 09:23:57 -0600
Jeff, Whoops! You are are correct and thanks for finding the error. That makes the current amplitute discrepancy 4 times less but the calculated current is still 32 times the reported current. Will w
/archives//html/Amps/2012-08/msg00504.html (14,086 bytes)

6. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Tue, 28 Aug 2012 13:26:24 -0600
David, you are correct, should be 200 mA for the starting plate current for that column. I have used a 3D printed plastic part as an air shroud around the screen contact ring on the TH628, operating
/archives//html/Amps/2012-08/msg00509.html (11,587 bytes)

7. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Tue, 28 Aug 2012 13:32:13 -0600
Dave It would be nice to have the time and a wide variety of materials to do this. Everyone seems to have a pet material for RF insulators. I did the measurements for materials i use on my job. All w
/archives//html/Amps/2012-08/msg00510.html (9,153 bytes)

8. [Amps] RF insulating materials - engineered plastics (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Tue, 28 Aug 2012 13:53:45 -0600
Several things could explain what is described: 1) The RF oscillator in the preheater is free-running. It is affected by the dielectric in the air capacitor zone. In addition, it is coupled such that
/archives//html/Amps/2012-08/msg00511.html (9,821 bytes)

9. Re: [Amps] RF insulating materials - engineered plastics (score: 1)
Author: David Kirkby <david.kirkby@onetel.net>
Date: Tue, 28 Aug 2012 21:01:57 +0100
OK. I was wondering if there was a simple way of measuring the properties of a dielectric without access to high power equipment, before incorporating it into high power equipment. I've been looking
/archives//html/Amps/2012-08/msg00512.html (11,325 bytes)


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