Chuck Kimball wrote: > > > Have you even looked it up?
I feel raped every time I walk into Hutton... I didn't keep the original message, so > I've lost what you really needed (Was the unistrut already in place? > Nope... I had to put that there... > Install I did last summer I spent: > > 10 pack of Hangers for 1/2" Hardline 16.00 > 10 Pack of Angle adapters 24.78 > 2 5 packs of minis for 7/8 hardline 5.47 2 packs of 1/4 spring nuts =4.00 The tower is 280' Do the math. Its enough to make a grown man cry. > That gives you 40' of tower support for less than $50. If you've got > round members, you can grab the Stainless Steel hose clamps locally and > don't even have the cost of the angle adapters. > > Given todays price of Gas, It doesn't take but a couple of trips to a > site to make up for the 'savings' of doing it cheaper. > > YMMV > > Chuck > > Jay Urish wrote: > > 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 > <http://www.andrew.com/search/BN_96221.aspx> > >> <http://www.andrew.com/search/BN_96221.aspx > <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 W5GM ARRL Life Member Denton County ARRL VEC N5ERS VP/Trustee Monitoring 444.850 PL-88.5
