I am in the process of putting up a Rohn 25 tower and have a good number of
questions about how to best go about this. I'll try to detail my situation
and what my ideas and questions are (it's probably pretty long).
I have 5 sections of Rohn 25 plus a 3 foot top section. I plan on
installing this at the rear of my house. The antennas on the tower would
basically consist of an HF tri-bander (right now a TA-33), a UHF beam and a
2m vertical. Additionally, I have some six meter Par Omni-Angles that I
would mount on the side of the tower.
My biggest difficulty comes in figuring how to best secure the tower and
make it safe. I've talked with some hams in my local contest club and have
some ideas on how to start the installation.
I have already installed a house bracket near the peak of my house. The
bracket is fastened to a 2x8 inside my attic which is lag bolted into the
studs. The 2x8 is about 10 feet long so the load on the house bracket is
well distributed across the studding in the house. Going down from there,
the tower goes through a hole in my deck to the patio below. Now, this is
where the first problem came in. Obviously, putting the base in concrete is
the best way to go. However, having a cement patio already in place and not
wanting to rip it up, this is not really possible. There are two options
that I have come up with from talking to others. The one I am leaning
towards is to use a Rohn BP25G drive in base with the three 2 foot drive
rods. I'd cut three 1.5 to 2 inch holes in the concrete and drive the rods
into the ground there. The other idea that another ham friend had would be
to get a flat base plate and bolt the tower base into the concrete slab. I
like the first option of driving the base into the ground the best.
So I pretty much have the base and house bracket situation figured out
unless anyone can tell me why either of these are bad ideas. Now for the
rest and most difficult part of the project. I have a total of 53 feet of
tower sections. The house bracket is located about 21 feet above the base
of the tower.
Question 1: Do I need to guy the tower above the house bracket? I was
originally hoping that I would not have to, but as I've thought about it, I
am thinking that this might be a good idea. It certainly can't hurt.
But then that brings up question 2: What would be the best way to guy the
tower? This is a loaded question. I really don't have the real-estate or
proper yard layout to do a "technically perfect" guy installation. I will
through out what I have in mind here and let the experts on this list tell
me if it is good or not.
One guy point I can run a good long length off the back side of the tower
out into a wooded area in my back yard. I am pretty confident that this guy
point would be very good and work well. The wooded area of my back yard
does rise in elevation compared to the rest of the yard and is actually
around the same elevation as my rooftop (about 22 feet higher than the rest
of the yard).
Now, I have to figure out where to put the other two guys. Well, they'd
need to be attached through the roof of the house. Is this a good or a bad
idea? My plan would be to bolt 2x4's or 2x6's across several roof joists in
the house. Then I'd pass a large eye bolt through the roof and fasten the
eye bolt into those boards. That would comprise my guy point. Is this a
good idea? Is it a safe idea?
Due to the size of the house and width of the roof, I have to chose between
the length of the guy wires and the angle at which they come off the tower.
The wider the angle between the guy wires, the shorter the wires will need
to be and the narrower the angle off the tower. The narrower the angle
between the guy wires, the longer they will be and the wider the angle off
the tower. Does this make sense? I need to have some advice about where I
should or should not put them or what is optimal.
I'm not so concerned about whether or not these guy points will hold with
the antennas that I have. I think they will. I am more concerned about
their strength when I am working on the tower itself and am climbing up it.
OK, I think I've pretty much laid out my situation. Any advice would be
appreciated. Now, I have a couple of final questions.
1.) Is a Tower Jack a good investment to purchase?
2.) Is there anything I can use as a substitute for a gin pole or do I need
to find one to borrow or purchase?
3.) Would a Hazer be a good idea to circumvent climbing of the tower?
Additionally, how would the hazer work on a guyed tower and with additional
antennas mounted on the side of the tower?
4.) Are kevlar guy wires recommended and are they worth their extra cost?
5.) What's the best climbing hardware to get?
I am trying to keep my whole setup as minimally instrusive as possible. I
just am not quite sure how to proceed from this point and I need some help
from people more experienced in this than myself. I am sure I will have
more questions that pop up after these get answered.
Oh yeah, one more thing. I am trying to get this done quickly before cold
weather sets in and the contesting season starts.
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