[Repeater-Builder] Re: slightly OT: securing feedline to the side of a tower

[skipp025]

Andrew is not the only source of hardline hangers. I buy pretty 
much the exact same snap in hangers with a generic brand name from 
Talley for about 1/3 the price. 

skipp 


> Great advice! I know how much the andrew hardware costs... 
> That would bankrupt this project.
> 
> I ended up going the all home depot route with galv unistrut 
> and strut clamps, minis  and my spacing is 8'. I will evaluate 
> the load on the feedline, and add additional supports in problem 
> areas..
> 
> 
> Jeff DePolo wrote:
> > 
> > 
> >  > Nope, because like you said, they would draw the feedline into the
> >  > strut, smashing it all up...
> > 
> > I regularly use cushioned clamps for attaching rigid feedline to
unistrut.
> > I usually buy them from McMaster-Carr, but I'm sure they're available
> > elsewhere. McMaster-Carr has them available in "tubing sizes" in
additional
> > to normal trade sizes- 1 5/8" or 3 1/8" rigid line is really 1
5/8" or 3
> > 1/8" OD. The soft plastic insert prevents the clamps from damaging the
> > line. Here's what they look like:
> > 
> > www.mcmastercarr.com - search for 32625T62
> > 
> > However, I wouldn't use them nor "mini's (Minearallac-type EMT
clamps) on a
> > tower, nor would I use any kind of off-the-shelf galvanized,
anodized, any
> > kind of plated unistrut on a tower. The galv on regular
electrical-grade
> > hardware doesn't hold up as long as most other tower-grade galvanized
> > structural steel. Valmont makes good hot-dipped galv strut if you
wanted to
> > go that route. And as always, use only high-grade galv or
stainless bolts,
> > nuts, and other hardware to attach to the tower. Never ever use
any kind of
> > plated steel components on a tower. They will quickly rust and become
> > semiconductors, and you will almost as quickly be banished from
the site
> > (assuming managed by diligent/competent people).
> > 
> > Personally, I'd stick with the real stuff - stainless round member
adapters
> > (hose clamps) or stainless angle member adapters (beam clamps), and
> > stainless butterflies or snap-ins. Do it once, do it right. If you
make a
> > few calls to local tower companies, I'd bet you'll find someone
that either
> > has a surplus that they'll see you at a fraction of the new cost,
or maybe
> > even a few 5-gallon buckets of hardware taken down that might
still be in
> > good condition and can be reused.
> > 
> > As far as spacing between brackets/hangers, it varies with wind
speed, icing
> > conditions, and line size. Here's Andrew's chart, based on EIA-222:
> > 
> > http://www.andrew.com/search/BN_96221.aspx 
> > 
> > 
> > Most towers around here come from the factory with brackets spaced
at 4'.
> > 
> > And remember, coax "hangers" really aren't hangers. They aren't
meant to
> > hold the vertical weight of the line - that's what hoisting grips (aka
> > Kellems grips) are for. The job of the hangers is to keep the line
from
> > flopping around horizontally in the wind, not to hold the weight up. A
> > properly-installed butterfly is only tight enough to keep the line
from
> > moving, not hold the weight.
> > 
> > As an alternative to butterflies or snap-ins, on big towers where
feedline
> > "bundling" is a necessity due to congestion and to reduce the
windload, the
> > traditional techinque is to install runs of rigid conduit the
entire length
> > of the tower (inside preferably), and then using tie wires (12AWG THHN
> > solid) or "band it" stainless straps to aggregate the lines
together around
> > the conduit, again at regular (4' nominally) intervals. Hoisting
grips are
> > still used every 200' to hold the weight of each cable individually.
> > 
> > Tie-wiring a cable directly to a leg is generally considered bad
practice
> > for a number of reasons. First, what do you do when you come to a leg
> > flange? If you hug the cable tight against the flange, the sharp
edges of
> > the flange creates a spot for it to wear through. If you form the
cable
> > loosly around the flange, it leaves it open for room to move and
create new
> > problems that way. Also, by being mounted to the leg, it becomes an
> > obstacle when someone else comes along and wants to attach an
antenna mount
> > to the leg. It's also more likely to get damaged by climbers and
rigging
> > lines. The list goes on and on...
> > 
> > Hope this helps.
> > 
> > --- Jeff
> > 
> > 
> 
> -- 
> Jay Urish CCNANetwork Engineer
> http://jay.unixwolf.net
> Home)972.691.0125Cell)972.965.6229
>

Re: [Repeater-Builder] Re: slightly OT: securing feedline to the side of a tower

[Kris Kirby]

On Sat, 2 Jun 2007, Ron Wright, Skywarn Coodinator wrote:
> I have also seen 1ft pieces of #14 house wire cut to 1 ft lengths used 
> with success, but have to make sure properly route arround tower leg 
> flanges or movement, and there is suppose to be some movement, will 
> eventually ware into feedline jacket.  Prefer the clamps, but at $3 
> each the wire looked good and did work or now since 1998.

There's "do it right" and there's "do it again".

--
Kris Kirby, KE4AHR  <[EMAIL PROTECTED]>
"The illegal we do immediately.  The unconstitutional takes
 a bit longer." -- Henry Kissinger

[Repeater-Builder] Re: slightly OT: securing feedline to the side of a tower

[Ron Wright, Skywarn Coodinator]

Jay,

Here on some of the towers that hold repeaters, cel phone sites, FM 
broadcast all with helix they use the proper clamp at 5 ft or less 
intervals.  See some at about 5" helix, but most either 7/8 or 1-5/8.

I have also seen 1ft pieces of #14 house wire cut to 1 ft lengths 
used with success, but have to make sure properly route arround tower 
leg flanges or movement, and there is suppose to be some movement, 
will eventually ware into feedline jacket.  Prefer the clamps, but at 
$3 each the wire looked good and did work or now since 1998.

73, ron, n9ee/r



In Repeater-Builder@yahoogroups.com, Jay Urish <[EMAIL PROTECTED]> wrote:
>
> Hi Folks,
> This weekend I will be un jury rigging a lame feed line install at 
my 
> repeater site. The tower is a 300' four sided guyed monster.
> 
> I am planning on using uni-strut on the side facing the building 
and 
> using butterfly clamps or EMT clamps to hold my feed line. I am 
open to 
> suggestions on the vertical spacing of my unistrut brackets. At 
what 
> interval should 1/2 - 7/8 and 1-1/4 heliax be secured?
> 
> Any suggestions?
> -- 
> Jay Urish W5GM
> ARRL Life Member  Denton County ARRL VEC
> N5ERS VP/Trustee  
> 
> Monitoring 444.850 PL-88.5
>

Re: [Repeater-Builder] Re: slightly OT: securing feedline to the side of a tower

[Gerald Pelnar]

Yes.

I was only confirming that I had misunderstood which clamps Jay intended to 
use. My original post said to use stainless.

Sorry for the confusion,
Gerald

- Original Message - 
From: "Laryn Lohman" <[EMAIL PROTECTED]>
To: 
Sent: Friday, June 01, 2007 8:59 PM
Subject: [Repeater-Builder] Re: slightly OT: securing feedline to the side 
of a tower


>
>> >
>> > OK Jay, in the electrical business we call those mineralac hangers
>> > (depending on where you live).
>> >
>> > Gerald
>
> Won't the Minerallac plated hardware begin to rust after a year or two
> outside, just like other plated stuff?
>
> Laryn K8TVZ
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
> 

[Repeater-Builder] Re: slightly OT: securing feedline to the side of a tower

[Laryn Lohman]

> > 
> > OK Jay, in the electrical business we call those mineralac hangers
> > (depending on where you live). 
> > 
> > Gerald

Won't the Minerallac plated hardware begin to rust after a year or two
outside, just like other plated stuff?

Laryn K8TVZ