[TowerTalk] What am I missing....balun

[Grant Saviers]

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 at 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 at contesting.com>
> Subject:	[TowerTalk] What am I missing....balun
> From:	"Jim Thomson" <jim.thom at 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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