[Amps] nylons

[Karl-Arne Markström]

Nylon should probably be avoided entirely in strong RF fields.

The dielectric material property list in ITT Reference Data for Radio Engineers
lists the dissipation factor of nylon as about 0.022 at 1 MHz , 0.02 at 100 MHz and 0.012 at 3 GHz
(actually decreasing with frequency). 
This is about two orders of magnitude worse than the best plastics and ceramics.

Coupled with its low softening point and dielectric strength, it seems that nylon is a 
low-priority choice as an RF dielectric. 
Much of the same also goes for acrylic plastics (Plexiglas and Lucite).

73/

Karl-Arne
SM0AOM

----- Original Message ----- 
From: "David Kirkby" <david.kirkby at onetel.net>
To: "John Irwin" <crazytvjohn at yahoo.com>
Cc: <amps at contesting.com>
Sent: Tuesday, March 15, 2005 9:06 PM
Subject: Re: [Amps] nylons


> John Irwin wrote:
> 
> >dudes
> > 
> >a large ace hardware store opened here last week , One block away.  I have noticed a lot of nylon items that look a lot like the ceramic standoff insulators, they come with a hole in the center,and some are taped for 6-32  or other simular sizes.  lenght every 1/8 inch or so,diameter 1/4 to 1/2 inch
> > 
> >How does nylon act in rf?    Like in a amplifier as used to support variable capacitors or inductors? Next to the plate choke.
> > 
> >Anyone put some in the pi coil and see if it holds up. or does it go up in smoke?
> > 
> >thanks
> >john kb9tc
> >
> 
> One other thing I forgot to add is that I have here some Ross HyperSPARC 
> CPUs,  which were from a Sun workstation. (Sun did not make this CPU, 
> but a 3rd party did). I know this particular machine had been run 24/7 
> for many years, and never broke down.
> 
> The heat sinks were attached using some sort of black plastic screws. 
> When I moved the computer, several snapped. The material (probably a 
> nylon) had become very brittle indeed. But these HyperSPARC processors 
> were known to run very hot and were subjected to this for many years 
> indeed. So a short-term test does not give the whole story.
> 
> 
> -- 
> Dr. David Kirkby, 
> G8WRB
> 
> Please check out http://www.g8wrb.org/ 
> of if you live in Essex http://www.southminster-branch-line.org.uk/
> 
> 
> 
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