> In a message dated 8/27/2006 12:28:30 P.M. Pacific Daylight Time,
> email@example.com writes:
>> On a Rohn 25/45/55 tower, is it standard practice to run hardline, coax
> control cables up the tower legs inside the tower or outside?
> Standard practice is to put them outside and secure them to a leg. The
> only reason I can see for running the cables inside the tower is the
> use of the tower as a Farraday shield for lightning protection.
Don't forget physical protection. We are almost surrounded by woods and we
get lots of high winds. Although the tower is a ways from any tree it's not
uncommon to see branches go whizzing by when the gust fronts come through.
About a month ago we had some strong storms coming in. I was getting ready
to head out on storm watch, but decided to shoot some photos from the back
yard of the front coming in. When the larger branches started flying I
decided the back yard was not place to be, particularly when I heard a tree
about 4' in diameter start to fail. That's quite a distinctive noise.
> Even doing that does nothing to prevent the lightning transient from
My cables are grounded at the base of the tower before they head in through
the conduit to the grounding bulkhead at the house entrance.
> traveling down the cables into the shack so it would be a waste of time
> much energy and colorful colloquialisms) to run them inside the tower
I would agree with hard line, but I'm in the process of moving all the
cables not only to the inside of the tower but inside the corner brace at
the guy atach points. It takes little more to put control cables and LMR-400
inside the tower, at least not in a 45-G. I'm adding a run of LMR-600 and
that too will follow the same route as the others.
> adequate building entry grounding.
>> Are cable ties the best way to attach the cables?
> Could be. Some guys like to use 6" pieces of wire to tie the bundle
> together; they're easy to take apart when you want to add or subtract a
Properly applied ties and wire will work fine, but I do not like cable ties
as they can easily be over tightened to the point of distorting the coax.
OTOH they should work fine if they are wide and one is installed about every
two or at most, 3 feet. In the case of wire it doesn't have to be tight as
it can be wrapped so tension will only pull it tighter, but like cable ties
it's small and there needs to be lots of them to prevent the weight of the
cables causing the wire to over tighten. I've seen cables nearly flattened
by cable ties and some very deep grooves from using wire as a support.
>> Seems like it would be a lot easier to string cables on the outside of
It's easier, but I'd not call it a lot easier. Even on the big system here I
prefer to run everything I can on the inside. In the past I've bundled the
cables up the outside of one tower leg and used lots of tape. It gets very
cold in the winter and hot in the summer, but I've not had any of it give
way. OTOH removing tape on a realy hot day sure is *sticky*<:-)) That
adhesive gets on everything.
> Bingo! I will only run cables inside a tower if the owner holds a gun
> my head - it's just too much hassle for little or no practical
>> More specifically, in addition to a fairly large complement of coax (5
> and control cables (7 runs), I'm thinking about putting a couple of runs
> 1-5/8" hardline (because that's what I have) up to my stack switch at
> 65'. Seems to me it will be difficult to feed this stuff into the tower
Now even 1 5/8" hard line would be easy to snake up the inside of a 45-G if
only going 65', but I would prefer to run it outside.
> it may be better to run it on the outside. Has anyone out there run
> hardline up a ham tower? How did you do it and how did you attach it to
Not having reached the microwaves yet and as it's only a 200 foot run to the
top of my tower I've never had a need for anything that large. (Plus it'd be
a bear to get through the conduit into the basement) <:-))
> First, you should use a hoisting grip or Kellum grip to pull the cable
> up -
> it weighs a couple of pounds per foot. It spreads the weight over a large
> area of the cable safely so you don't damage it. Then attach the hoisting
Special care applies to even regular coax when you are pulling up long runs.
Some cables like 9913 are particularly fragile and can be easily kinked.
> to a brace and it'll support the whole weight. Using a hose clamp or two
> another way to secure it. Then black tie wraps will finish it off. Do not
> white tie wraps - they're not UV resistant and will fall apart in a year
It depends on the formulation in the ties. I've never seen white, or clear
ties hold up and I've used some large (wide) black ones that I could snap
with two fingers after the ties had beed on the tower just over a year. I
was going to move/relocate a portion of the coax. When I started to release
the fastener it broke with just finger pressure. It was a good thing I had
them about every two feet. So, don't depend on "black" being UV resistant.
Check the package to make sure they are UV resistant. If it doesn't say so
they probably aren't. Good, large ties are *Expensive*
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
> Steve K7LXC
> TOWER TECH
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