and wall bracket the tower to the building...saves a lot of trouble with the
supporting roof
Mark N1UK
----- Original Message -----
From: "Gary K9GS" <garyk9gs@wi.rr.com>
To: <towertalk@contesting.com>
Sent: Saturday, 18 February, 2012 8:58 PM
Subject: Re: [TowerTalk] Request for Advice - Rohn 25 vs TRI-EX HZN 471
> Seems like an awful lot of trouble when you can just buy an extra
> section or two of used Rohn 25.
>
> Just saying......
>
>
>
> On 2/18/2012 6:33 PM, Bruce Ward wrote:
>> Mark,
>>
>> You make a very sane suggestion.
>>
>> My reason for putting the tower on top of the building, if I do, is to
>> get an extra 8' to 10' of height. The building will be sufficient to
>> handle the 1100 pound weight plus the horizontal wind loads.
>>
>> The tower site is covered in 60' plus trees and there is a similar
>> height hill with similar height trees between my tower and the far end.
>> I need to get above the trees plus above the fresnel zone so I want to
>> go as high as I can.
>>
>> If I use the Rohn 25G we will add sections until we are high enough.
>> This method could mean that I have to build sufficient structure to
>> bracket even higher than 35'. I would place the bottom section Rohn 25G
>> on the ground (a concrete base) and bracket it to a pole embedded into
>> the building.
>>
>> If I use the the TRI-EX I am stuck with its 70' height plus a 10' mast.
>> Since it is a one shot deal I would like to start as high as I can.
>>
>> Thank you.
>>
>> On 02/18/2012 06:19 PM, Mark Robinson wrote:
>>> I am not a mechanical engineer but why don't you put the tower in the
>>> ground
>>> and the building next to the tower.
>>>
>>>
>>> Mark N1UK
>>>
>>>
>>> ----- Original Message -----
>>> From: "Bruce Ward"<Bruce@IPIntel.com>
>>> To:<towertalk@contesting.com>
>>> Sent: Saturday, 18 February, 2012 6:53 PM
>>> Subject: [TowerTalk] Request for Advice - Rohn 25 vs TRI-EX HZN 471
>>>
>>>
>>>> I am setting up a tower (my first) to get internet service. The
>>>> antennas will be less than 2 square feet of wind loading combined and
>>>> could be even less using 2 11x14" grid antennas.
>>>>
>>>> My plan is to build a 10'x10' 9' to 10' tall block building on a slab
>>>> that is larger in all directions. This building will will have a
>>>> concrete roof with rebar and wire in all concrete. The blocks will
>>>> have
>>>> rebar and concrete in every cell. The structure will use 12 to 15
>>>> yards of concrete plus 400 concrete blocks providing an over 45,000
>>>> pound base for the tower. I have a civil engineer friend who will be
>>>> involved in the final design of the building. The building is dual
>>>> purpose, it will provide a secure home for my servers and a stable base
>>>> for the tower.
>>>>
>>>> Now for the difficult part, I do not have room for guy wires.
>>>>
>>>> I am trying to decide between two options
>>>>
>>>> 1. I have 9 full and a top section of Rohn 25G in my yard waiting to be
>>>> be installed. Currently Rohn rates the 25G for freestanding use up to
>>>> 40' with 1.4 square feet of wind loading. From reading online it
>>>> sounds
>>>> like Rohn 25s have been used for decades even higher without guy wires.
>>>> I do not want to risk stretching beyond Rohns specifications. I have
>>>> access to 40' lengths of 8" pipe. If I go with the Rohn 25G my
>>>> intention
>>>> would be to embed a 40' section of the 8" pipe into the building and
>>>> bracket to that pipe up to 35' or so then have the tower extend another
>>>> 35' to 40' above the pipe. All the metal would be isolated from the
>>>> ground and properly guided with a ground rod to avoid corrosion issues.
>>>>
>>>> 2. There is a TRI-EX HZN 471 available locally. I would have jumped on
>>>> this one earlier but it is worth more the the current owner than it is
>>>> to me. This is a 70' (71'?) crank up tower with a motorized winch.
>>>> The
>>>> motor is broken and would need to be replaced. The tower is free
>>>> standing with the exception of three diagonal pipe braces that connect
>>>> from the top of the bottom of the 4 sections to the ground around 10'
>>>> out. I like that this tower is freestanding and I believe I could do
>>>> away with the braces if I bracketed the tower at the same location to a
>>>> sufficiently strong structure. If I used this tower I would likely
>>>> build a 3'x3' column of solid concrete into my building and place the
>>>> tower on top.
>>>>
>>>> I would very much appreciate any suggestions and advice.
>>>>
>>>> Thank you.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
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>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>> _______________________________________________
>>>
>>>
>>>
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>>
>>
>>
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>
> --
>
>
> 73,
>
> Gary K9GS
>
> Check out K9NS on the web: http://www.k9ns.com
> Greater Milwaukee DX Association: http://www.gmdxa.org
> Society of Midwest Contesters: http://www.w9smc.com
>
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>
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