[TowerTalk] UV and WX deterioration of THHN insulation and effects at R

[Guy Olinger]

That would be nice, something that can be drawn across a couple
hundred feet in a walking motion.

Manufacturer, model number and retail source URL??

73, Guy K2AV

On Mon, Dec 26, 2016 at 9:28 AM, GARY HUBER <glhuber at msn.com> wrote:
> All that is needed is a cheap cable insulation ripper.
>
> 73 es DX,
> Gary - AB9M
>
>
>
> Sent via the Samsung Galaxy Tab® 3 Lite
>
>
> -------- Original message --------
> From: john at kk9a.com
> Date:12/25/2016 9:15 PM (GMT-06:00)
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] UV and WX deterioration of THHN insulation and effects at R
>
> Your post leaves me with many questions.
>
> What are the actual measurements? What is the reason that PVC (which is
> pretty tough as well as moisture resistant) is causing this issue?  What is
> you method for rapidly stripping THHN?
>
> John KK9A
>
> To:     Towertalk <towertalk at contesting.com>
> Subject:        [TowerTalk] UV and WX deterioration of THHN insulation, and
> effects at RF.
> From:   Guy Olinger <k2av at contesting.com>
> Reply-to:       k2av.guy at gmail.com
> Date:   Sun, 25 Dec 2016 03:50:11 -0500
>
> First of all, and most important, a joyful holiday season and a prosperous
> New Year to all of you.
>
> Now down to microscopic issues that will probably have no bearing on World
> Peace...
>
> Let's be clear that I stand by my prior statements against using unstripped
> THHN at RF, respectfully, others' contrary statements notwithstanding.
>
> We have careful measurements. We can't just walk away from measurements. A
> measurement is a measurement, not an opinion. We're stuck with
> measurements.
>
> The effect in one case, losses from deteriorated insulation on elevated
> THHN radials were the same as if one had placed a 15 ohm resistor between
> the coax center conductor and the vertical wire. ***The owner was unaware
> and thought everything was fine.*** How this came to light is an involved
> story.
>
> Someone with a low band dipole in the air using unstripped THHN may be
> paying quite a penalty, especially if it's been up a long time. It would
> have developed very slowly, very sneaky. Not like having a branch drop on
> your antenna and having the SWR suddenly go bonkers.
>
> I find the defense for using UN-stripped THHN outdoors and for RF
> intriguing. Even more intriguing, stuck with the prospect that THHN might
> be bad for us, some propose going to a different (less common, more
> expensive?) THH-something variant hoping for a better insulation lifetime,
> while admitting the new THH-whatever will probably go down from UV as well,
> just later. ???????  You're hoping for what advantage from the insulation?
>
> With the single exception being some posters to this reflector, everyone I
> know locally or have corresponded with, or talked with on the phone on this
> subject, they all bought a spool of THHN from a Home Depot/Lowes/etc for
> outdoor antenna wire because it COST LESS, maybe half the price of same AWG
> from sources that sold it as bare wire.
>
> Likewise if they didn't strip it, the single reason they did not strip it
> was because it appeared to be a lot of work. Some tried to strip it but had
> the problem of the knife digging the copper. They had never seen a
> description of "the method".
>
> It turns out that it is possible to strip 250 feet of THHN in the time it
> takes to walk the length of the wire, if you use the method. The limiting
> factor is the distance you have available to stretch it out before you
> strip it. Everyone who has seen it done, later says it's obvious once
> you've seen it. Once they have seen it done they all strip the THHN and put
> up the solid bare wire.
>
> It's impossible to NOT take some hit with still-insulated THHN vs.
> stripped. If nothing else, they're out for the dielectric loss of the
> insulation.
>
> Then there are potential gradually increasing losses as the UV deteriorates
> the material, with clearly proven examples of severe end-stage losses with
> the UV deterioration.
>
> Happy Holidays everyone, and back to the egg nog.
>
> 73, Guy K2AV
>
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