Several comments:
On Nov 11, 2007, at 5:20 PM, AD5VJ Bob wrote:
> I said 03 feet of gravel I meant to say 03" of gravel sorry abt the
> typo.
6" of gravel is more like it.
>> I am digging a hole to install my rohn 25g tower.
>>
>> I am going up 40 feet at this point (ONE EACH THREE ELE
>> TRIBANDER AND ROTOR) with plans to add to the tower later
>> with additional sections.
>>
>> I will be using part of a section in the ground (4 feet I
>> think) and then attaching the rest I suppose by using a home
>> made gin pole.
>>
>> The dimensions as I understand it for the hole should be:
>> 2'X2'X4'
Is this for a free-standing, bracketed or guyed tower? The 2x2x4
dimensions are correct for a bracketed or guyed tower. For free-
standing, the base dimensions are much larger -- 4x4x4.
>> Before I go out there in this rocky soil and break my back
>> with my pick and shovel I would just like to know that the
>> dimensions and procedure are correct. :)
>>
>> Then I lay 3' of gravel which I have, center the section in
>> the whole, try to devise someway to hold it still after
>> checking it with my level and plumb-bob and pour.
>>
>> No guy wires at this point in time. 20 meters here I come.
If this is free-standing, then you have two problems. 1) your base
isn't big enough. 2) 40 feet of Rohn 25 is barely strong enough to
hold itself up in 70 mph winds. A typical small tribander is 3-6
square feet of wind load. Rohn 25 free-standing 40 feet can only
handle 1.5 square feet with no ice.
If you are bracketing this tower to a structure, then your base is the
correct size, and so long as the bracket is within 25 feet of the top,
you shouldn't have a problem.
I would not install this tower without guying or bracketing.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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