What do you plan on putting on it and how do you plan on guying it?
Typically a guyed tower doesn't take all that much of a base. As Mark
said, it's only to keep the tower from sinking. I'll add "or to keep the
base from moving sideways.
I've put up many 60 to 90' towers using what are called "dirt bases"
with a tribander and maybe a VHF/UHF set of antennas on top and never had
a problem with any of them.
With the 10' 45G I have now along with the large antennas I have about 2
yards under the tower and between 3 and 4 yards under each guy anchor.
It's guyed at 3 levels.
73
Roger (K8RI)
On 11/3/2010 10:05 PM, Mike wrote:
> Thanks Tommy,
>
> The commercial "foundation" company crew brought a 30" auger, drilled the 4'
> hole in less than 5 minutes, set a sonotube, dropped the spec'd rebar cage
> in, c/lined the pier pin and I OMG set the base plate over and discovered
> the fubar. Plan "B" is to now have them set a rectangular 36" square
> (inside) 2'X6" form on grade centered around the 30" existing hole...they
> will cut the 6" above grade sonotube down to grade level first and add
> appropriate wire mesh or rebar in that 36" square form. Crossing my fingers
> and knocking on wood....
>
> 73, Mike
>
> _____
>
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Tommy Alderman
> Sent: Wednesday, November 03, 2010 4:48 PM
> To: 'Tower and HF antenna construction topics.'
> Subject: Re: [TowerTalk] Rohn 45 tower and base
>
>
>
> No - you are exactly correct!
>
> I did not follow the Rohn instructions and used the CB2 foundation. My pier
> pin base plate is offset as you say, but with the larger 36" x 36" CB2
> foundation, the base plate does not overhang. My tower is only 70' high, but
> with a 90' 45G, I sure would phone Rohn and get confirmation that their
> Buyers Guide is correct, just for the peace of mind!
>
> Tom - W4BQF
>
>
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of MIKE
> Sent: Wednesday, November 03, 2010 2:33 PM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Rohn 45 tower and base
>
> I am trying to get a 90ft 45G tower installed before winter sets in and the
> required base in the mfg guide is a CB1, 30" round or square (more
> concrete). Found out the hard way that the steel base plate hangs off the
> 30"circular pier on two sides. Digging into an older Rohn catalog, I found
> in the fine print that I require a 36" circular pier! Aside from this all
> the drawings I've found specs the pier pin to be "centered" whether or not
> you use a round or square form.
> The 20"X24" concrete base plate pier pin hole is offset and the plate (and
> tower) will not be centered over the c/l of the foundation. Am I missing
> something here?
>
> Thanks, Mike K4EAR
> _______________________________________________
>
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