[TowerTalk] Feedlines: inside or out on tower?

Jay Kesterson K0GU k0gu at verinet.com
Mon Aug 20 13:49:08 EDT 2012


I have a Rohn 45G tower with one run each of 1/2" and 1 5/8" Heliax 
inside the tower plus a run of 3/4" CATV hardline. Another 45G with a 
run of 7/8" Heliax. It really goes in fairly easily. I rigged a pulley 
just below the middle of the rotor plate to pull up the coax. Someone 
needs to climb with the coax as it goes up as the end will inevitably 
snag on rungs on the way up. Someone needs to feed the cable in the 
tower at the bottom as someone/something pulls the coax up with the rope 
slowly.

Heliax jacket is strong and somewhat slick so it slides in the tower 
fairly easily at the bottom with the help of someone pushing it into the 
tower as someone pulls on the rope. 1/2" and 7/8" Heliax aren't so thick 
that they couldn't be damaged if one pulled hard on the rope without 
someone feeding in the coax at the bottom. My CATV hardline has no 
jacket and the aluminum shield is kind of soft so extra care (read go 
very slow) is needed. 1 5/8" Heliax would perhaps break you before you 
broke it. :-) But if you are using a device with mechanical advantage to 
pull it up (advisable, it's heavy) you could probably do some damage to 
something.

I rather foolishly installed all these coaxes by myself. I fed a couple 
of feet of coax in the tower, pulled the rope a little with my truck and 
climbed up the tower a few times when the ends snagged. It wasn't a lot 
of fun by myself but I am kind of hardheaded when I want to get 
something done. Get a couple of friends over, feed in a couple of feet 
of cable at the bottom at a time and it should go smoothly (well as 
smoothly as antenna work ever goes).

Oh if you use really big hardline you might not be able to get it in a 
the very bottom of the tower. My 1 5/8" goes in the tower about three 
feet above ground. But likely could have gone in one rung lower. I would 
suggest putting it in the tower where you have the entire distance 
between two rungs. Although with smaller sizes you might be able to get 
away with less distance if you go slow. Just don't try anything that 
even comes remotely comes close to kinking the cable. If in doubt back 
it out a couple of feet and try again. You will get the feel for what 
will or won't work pretty quickly and it isn't that hard.

73,  Jay  K0GU



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