Rob,,,, first... your base is quite a bit of overkill...For Rohn 25 you
only need 4 X 4 X 4 at the most...I think 3 X 3 X 3 is plenty.
Before that amount of concrete can move the tower will buckle. Rohn 25
is
designed not to go over 30 ft without guy wires.(freestanding)
And with very little wind load (antenna). 50 ft of unguyed tower is
asking
for a disaster !!!!!
A friend of mine in Kentucky, K8MWO, has a 50 ft with a hazer, and a
KT36XA.
He has it guyed once I think at 40 ft. He drops the guys with no wind
blowing, and the hazer comes down and he says maneuvering the guys around
the hazer travel
Is the "tricky" part of it. But he has NO PROBLEM with this set up. He
will
gladly answer any emails to help you with a similar setup
As far as grounding,,, ground rods should NEVER go inside concrete. I
ground my tower with a 10 ft rod at each leg, with solid copper
Coming off each leg to the rod. Be sure and ground the guy cables at each
anchor with at least an 8 ft rod. You can spend as money on grounding
As you wish,, but this is a good reasonable setup. I would avoid cadwelds.
2
clamps per leg, and 2 on the rod,, you will do good. Do NOT use anything
That will rust up for clamping. If you can get a ground off your electric
service to the tower grounds,-even better.
Your 3 inch pipe WILL get water in it... drill some small drain holes at
the lowest point. If the pipe is laying in a small bed of gravel,, this
will
Enhance draining,, and not get dirt clogging the holes.
AND all this is MY OPINION... Good Luck,,, Dan N4GNR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Rob
Matherly
Sent: Monday, April 25, 2016 5:42 PM
To: TowerTalk@contesting.com
Subject: [TowerTalk] New Tower Install
Hi All -
First time poster to the list, long-time lurker.
I'm getting set to install my first tower after having been in the hobby
for nearly 20 years. I'm going to install 40' of Rohn25 with a Hazer.
I'm
going to set it in a 4x4x5 block of concrete that I have the option to
make
it taller later on (without the Hazer, of course.)
Please advise if I am correct: I do not need to guy the tower given the
base size and height, correct? I've been told I can go up to 50' unguyed
by some, but others say anything over 40' needs guyed.
Regarding grounding: I've seen different ways of doing it. What is the
best way to ground the tower? Rod at the bottom of the hole? Rod to the
side of the slab?
I'm going to feed it underground with a 3" CPVC line coming up into a
weatherproof box mounted a short distance from the tower. Do I need to
tie
the ground bus in the cabinet to the ground in the tower, or do I need to
keep them separate?
Thanks
Rob
w0jrm
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