Ron,
From a base perspective I would go with a pier pin for two reasons;
- If you ever want to go to a different size tower like 45g or 55g
you will be able to easily. This does make it challenging to install
the first few sections until they are guyed. Make the base, as you
plan, the correct size for the larger tower. I don't have my Rohn book
in front of me, but I believe both 25g and 45g call for base cb1.
- I like a pier pin so the tower can twist a bit from high winds or
the torque of the antenna turning. Just makes sense to me not to have a
fixed base which would probably cause additional stress on the tower
(I'm not an engineer but this just makes sense to me).
Put your guy anchors out far enough (if you can) so you can side mount
and rotate antennas lower down on the tower. My 80' tower has guy
anchors out 80' which allows me to side mount as well as go higher
(albeit not much higher) some day.
Also, use philystran guy cable if you can so you do not have interaction
with antennas.
Do not attach guy wires to the very top section. This will make it
easier to remove the top section if you decide to go higher as well as
giving you maneuverability while working on top of the tower. Care does
need to be taken how much mast/antennas sticks out the top.
Good luck.
Rich - N5ZC
On 3/24/2014 7:30 AM, Ron Rosson wrote:
Well the weather here in Colorado is finally getting to the point where I need to get of my backside
and start setting plans to get my first tower put up here in Loveland, Co. I have 6 10’
sections and one top section plus 1 8’ section (all 25G). Depending on who I have talked to
in person I have got mixed information on using burring the 8’ section or setting a base
plate for the tower. Which is the better route? Also In my google searches I have found not tied and
true method (free info) for the depth of the whole to dig for the base and how to set the rebar be
it I go with encasing a tower section in cement or with purchasing a base plate for the tower. Below
is what I know that I need to do:
- Cement needs to be 3000 PSI rated
- I want to go bigger on the whole just in case I want to go higher
than what I currently have on hand
- Get with local County to make sure I am ok with how I want to get
this accomplished.
- Once the cement is poured I have a minimum of 30 days of curing
before I can start putting sections together
- If it falls it has to land on my property and not any of my neighbors
:)
What I do not know:
- Best way to accomplish digging of the hole and setting it up for the
tower
- Disturbed or undisturbed
- Rebar pattern
- Dimensions (x by y by z (where z is the depth)
- How to properly setup the anchors for the guy wires
- Can I guy to the same point from different heights if my height requires a guy at
“a" feet and another at “b” feet.
All guidance and pointers is greatly appreciated. If you are local I am open to
a visit for some personal pointers to see the lay of the land (so to speak)
TIA
--
73 de KF5JRA
Ron Rosson
ron@oneinsane.org
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