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Re: [TowerTalk] Feedlines: inside or out on tower?

To: "Jim Hoge" <>, "towertalk" <>
Subject: Re: [TowerTalk] Feedlines: inside or out on tower?
From: "Gene Smar" <>
Date: Sun, 19 Aug 2012 11:38:42 -0400
List-post: <">>

     Professionals install the cables on the outside of towers because it's 
easier to do so when you're on the clock.  In that case there is no 
particular advantage to trying to mount 2-inch nominal cable inside the 
tower structure.

     However, some Hams, myself included, install coax and control cables 
inside the tower to provide some shielding effect to the cables if we intend 
to load the tower on the low frequency bands.  If we shunt-feed our towers 
or use the tower as part of any other antenna system such as a half-sloper, 
having the coax cables inside the tower structure will keep them out of the 
calculus for the radiating elements of the system (Faraday cage effect.) 
That is, these cables will not become part of the outside of the tower that 
radiates the lowband signal.

     BTW - the three or four runs of RG-213 that are on my Trylon tower are 
easily hidden inside the angle steel of each leg.  To attach to the tower I 
wrapped a single length of #12 solid insulated house wiring around the coax 
bundle, twisted it a couple of times, then ran a wire end through a 
pre-drilled hole and twisted both ends together.  With this method I can 
re-enter the bundle to change or add cables, then reseal a few more times 
before I have to replace the wire.

73 de
Gene Smar  AD3F

----- Original Message ----- 
From: "Jim Hoge" <>
To: "towertalk" <>
Sent: Sunday, August 19, 2012 11:10 AM
Subject: [TowerTalk] Feedlines: inside or out on tower?

After reading John's (KK9A, P40A) post regarding tower painting, I have a 
question for the group. While I would be hard pressed to recall a tower I 
have worked on that has not had its feedlines and control cables run on the 
inside of leg, it is obvious from his post that not everyone does so. What 
is the thinking behind running the cables on the inside or the outside? BTW, 
I've even seen hardline run on the inside of 45 and 55, glad it wasn't me 
who had to install it.

Jim W5QM

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