Nice to have the clarification of FEP vs PTFE.
A bit more FEP data from DuPont:
https://www.chemours.com/Teflon_Industrial/en_US/assets/downloads/teflon-fep-film-properties.pdf
"Long Time Weatherability
Inert to outdoor exposure; no measurable change after
20 years in Florida
High transmittance of ultraviolet and all but far infrared
radiation "
Anecdotally, for 30 years I've been using up a 933 ft spool of Thermax
RG142 silver plated double shield that I scored at a Raytheon missile
division surplus auction. So I am pretty sure it is Mil spec and it is
marked so. Open FT240-31 chokes wound with it and in the sun for 5
years show no degradation. For beams I put the chokes inside plastic
J-boxes since the 142 center wire is silver plated CCS and won't take
lots of repetitive bending from wind and rotation forces. Happy at QRO
all HF bands.
The DuPont formulation guide shows the 9xxx series as the most suitable
for wire insulation.
https://www.chemours.com/Teflon_Industrial/en_US/products/product_by_name/teflon_fep/index.html
RE Chinese knock offs - caveat emptor - Duh.
Grant KZ1W
On 2/22/2017 7:01 AM, john@kk9a.com wrote:
Taping RG-393 is a good precaution and I would do the same if was using
that on an antenna where replacement would be difficult. I bought a used
antenna once and some RG-142 teflon coax with a tan jacket was still
attached. I am not sure how long it was outdoors but it looked in perfect
condition. As an experiment I had a piece of teflon coax outside and saw
no degradation after a couple of years so I think FEP is pretty tough. I
do not understand the "will only last 15 minutes" comment.
John KK9A
To: <towertalk@contesting.com>
Subject: [TowerTalk] What am I missing....balun
From: "Jim Thomson" <jim.thom@telus.net>
## The outer jacket on 393 and 142 is not PTFE. PTFE is used for the
dielectric inside. PTFE aka terflon.
## Outer jacket is FEP-9 . These cables are made by everybody and their
dog.
Made in the UK, china, rfs makes it, so does times microwave, belden, and a
bunch more.
I suspect its either a quality control issue, or a tweak in the formulae,
rendering it semi useless
for UV outdoors. Im not going to take a chance, and will 88 or 33 tape
it the
entire length.
Which is not vey much, so not an issue. Its too expensive as is, and 33
or 88
tape is cheap
insurance.
Jim VE7RF
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