Amen, Karl-Arne
The styrenes - such as ABS - are quite good around RF.
On Mar 15, 2005, at 1:31 PM, Karl-Arne Markström wrote:
> 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@onetel.net>
> To: "John Irwin" <crazytvjohn@yahoo.com>
> Cc: <amps@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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>
>
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Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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