[TowerTalk] UL listed protector for ladder line

[Paul Christensen]

>"It might be a great idea until the ATU fails. It is mechanical, it will eventually fail, and usually at the worst time."

All antennas are mechanical and often break at the worst time.  At least if an ATU fails, it's at ground level and conveniently fixed.

Coaxial-fed dipole antenna center insulators often break and coax degrades over time.  Some coaxial center insulators are heavy (e.g., Balun Designs).  Nor are they waterproof; I've had several.  Center insulators with SO-239 connectors require very good weatherproofing.

With balanced feeders and an ATU, there's no discontinuity nor splicing of any kind between the transmission line and the antenna.  It's one continuous piece of wire: the line wire meets the antenna center insulator, exits, and continues on to form the antenna without interruption.

The same is true with a folded dipole where one wire forms the line and antenna without interruption.  When there's ample wire bending radius at the center and end insulators, there's zero antenna maintenance up in the air unless there's breakage from a severe weather event - but that applies to all antennas.

Paul, W9AC


-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Jim Lux
Sent: Monday, June 16, 2025 10:32 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] UL listed protector for ladder line






I have seen a strategy used in achieving compliance.

"Shall use a UL listed device" (and they don't call out a specific standard), then the implementation uses something with a standard that isn't necessarily appropriate, but is, in fact, listed.



On Sun, 15 Jun 2025 14:40:19 -0700, Jim Brown <jim at audiosystemsgroup.com> wrote:

On 6/15/2025 1:49 PM, Martin A. Flynn wrote:
> I asked our municipal POC to source a list of protectors that pass the
> insurance companies muster,  here's a link to what was provided
> https://
> http://www.po/
> lyphaser.com%2FThemes%2Fpolyphaser%2FContent%2Fassets%2Fpdf%2FINF-PP-U
> L497E-&data=05%7C02%7C%7C1385a6c4212244f1c38a08ddace2c7ff%7C84df9e7fe9
> f640afb435aaaaaaaaaaaa%7C1%7C0%7C638856812224429304%7CUnknown%7CTWFpbG
> Zsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFO
> IjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=5O8tAOtmgrj9HoRG2HD8pL
> 81hgTHlfO9GILn3Lgm%2FGo%3D&reserved=0
> Flyer_V3.pdf
>
> We noted this is UL497E and not the UL452 (radio & television
> receiving
> equipment) / UL 1449 (surge suppression) that was originally called
> out, and were told this is the only option, and specifically "told not
> to press the issue".

And, as noted, they won't work for your chosen antenna, for the reasons noted. You should probably pursue one or more of the options for antennas that are relatively well matched to coax on their operating frequencies.

73, Jim K9YC

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