w1jr wrote:
< snip >
> In 1989 I helped develop a low cost PTFE coax for the Cushcraft
> Corporation. They needed a cost effective coax for installing mobile
> antennas in automobiles that wouldn't melt if placed near catalytic
> converters etc. Cushcraft marketed it as "Ultra Link" coax. Ultra
> Link, as I recall, is about the diameter of RG58. It uses PTFE
> (instead of teflon) dielectric.
k6gt questioned: Hmmm. I was under the impression that "Teflon" IS "PTFE".
I thought
that Teflon was DuPont's trade name for PolyTetraFluoroEthylene.
<snip>
quoth wikipedia:
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer which finds
numerous applications. PTFE's most well known trademark in the industry is
the DuPont brand name Teflon, as DuPont initially discovered PTFE.
<snip> <summary appendage> Roy Plunkett is credited with the serendipitous
discovery in 1938.
To which I add:
Gore later worked with extruding and drawing the stuff, to discover that its
physical and dielectric properties changed with stress. Micro pores
were created by the process. Which is why Goretex fabric foul wx gear
breathes.
In high-precision measurement systems, distinction was made between teflon
and PTFE, as to differences in dielectric properties. If you're measuring
charge..and using teflon cables...it could take several minutes to discharge
the teflon cable capacitance to allow a proper measurement....whereas PTFE
has a lower dielectric constant, due to the micropores. i.e. Same stuff,
slightly different form.
N2EA
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