[Towertalk] Feedlines inside or out?

[Bill Hider (N3RR)]

There are several considerations, but addressing the lightning issue for
coax attached to the outside of a tower:

There is no lightning issue if you ground the shield of the coax at the top,
close to the tower just before the coax leaves the tower to go to the
antenna AND ground the coax shield at the bottom of the tower before the
coax leaves the tower and continues towards the house/SPG, etc.  Use
recommended grounding practices including ground kits, etc, at the top and
bottom of the tower.  (SEE: http://www.erols./com/n3rr) Also, see PolyPhaser
references mentioned in my site.

Now, other considerations include:

Climbing methods and potential interference to climbing from the attached
coax.  Climbing towers is a personal issue and depends on the type of tower.

Type of tower (Angle/tubular/crankup).  This will help determine how you
attach coax, climb, etc.

Wind loading: On angle towers, nesting the coax inside the inside angle,
inside the tower, will not increase wind loading of the tower.  On tubular
towers, wind loading is only slightly controllable - coax inside the tower
would have slightly less wind loading since the horizontal and diagonal
tower elements would shield/mask the coax wind area somewhat.

Coax attachment bracketry.  It may be easier to attach the coax outside the
tower, riding up on a tower face rather than on a tower leg.

That's all I can think of.  Any others?

Bill, N3RR


----- Original Message -----
From: "Steve/n0tu" <n0tu@codenet.net>
To: "TowerTalk" <towertalk@contesting.com>
Sent: Wednesday, May 29, 2002 8:15 AM
Subject: [Towertalk] Feedlines inside or out?


> I've seen a few tower installations with feedlines were mounted on the out
> side of the tower instead of inside. From what I've read and heard all
> cabling should go up the inside, Right?! The case where I saw it on the
> outside was 7/8" hardline or maybe larger? I admint large diameter
hardline
> would be a real bugger to haul up the inside of the tower!
>
> So what's the rule? Inside or out? And if you do run your hardline up the
> outside, are you at greater risk of leading a that dreaded strike down the
> feedline into the shack? Common sense seems to say better to stay inside
the
> tower w/cabling. But common sense is sometimes mislead. Please advise.
> THANKS!
>
> Steve/n0tu
>
>
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