[TowerTalk] Now What?
K7LXC
K7LXC@aol.com
Tue, 14 Apr 1998 10:38:43 EDT
In a message dated 98-04-13 23:34:04 EDT, no6x@inreach.com writes:
> I have read the many posts regarding "to pour or not to pour?"
The question is not whether "to pour or not to pour", it's do I follow
the Rohn specs or do I hip-pocket engineer it? The LXC Prime Directive is "DO
what the manufacturer says". I don't recall any mention in the Rohn catalog of
installing the bottom of the tower in dirt without the benefit of concrete or
rebar. The "I done it this way for 25 years and it ain't fallen down yet"
approach is WRONG!
Granted, a properly housebracketed tower that meets Rohn specs but has
the base in the dirt isn't a big candidate for catastrophe but that's not the
way it should be installed.
> I know have questions about my origional Idea.
> Being a renter and a Ham I am a bit challenged.
> I am planning a tower install sometime this year, and have been doing lots
> of reading and asking questions. Up to this point my thought was to just
> dig a great big hole and fill it with concrete and hope like hell the
> Landlords did not find out how deep it was.
Pour the concrete so that it is below grade and cover it with dirt when
you leave. In the worst case, you can rent an electric jackhammer and take out
all or most of the concrete when you move.
> Then the thought of moving has crossed my mind, now comes the NOW WHAT?
> I was thinking of something freestading to avoid the guy wires, and would
> like to get something 60-70 feet with the hopes of stacking a pair of
> tribanders, maybe 40/70. However If a guy was to use some of the before
> mentioned methods would it still be structurally sound enought not to
> crumble and kill a inocent kid . The Idea of a 4-5 foot hole with the tower
> stuck in then 1 1/2 inch rock covering sounds nice.
Nice but wrong.
> Will it handle the load of say 70 feet of Rohn 25?
"Handle?" What do you think an engineer will say about it? Or a
commercial installer?
> Or maybe Rohn 45 should be used?
> Could I get buy with a house bracket at about 15 feet and 1 set of guys for
> a pair of tribanders? (most likely one fixed and top rotatable)
> I see a plus to this as worst case I might destroy one section of tower and
> only loose a couple hundred bucks, instead of all the material and concrete
> which is much more expensive.
> Ok enough babbling...what to do, what to do???
First of all Tulare County is a 70 MPH windspeed zone - the lowest
rating they give - so you don't have big winds to worry about.
Sixty feet of 25G will handle approximately 16 sq.ft. of antennas @ 70
MPH so your stack of tribanders is feasible. It's a little better than 45G as
it's easier to rotate antennas around the 12 inch face than the 18 inch face
of 45G. The big trick is to make sure your guy anchors are a long ways out
there (maybe 100% or more) so that you have enough room under the guys to
swing the lower antenna.
Rohn catalogs are five bucks from TOWER TECH.
Cheers, Steve K7LXC
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