Reading from my Rohn Engineering Manual,:
House brackets must be used and must be mounted at least 12 feet above ground
to be effective. #25 tower should not extend more than 33 feet above the
bracket.
This is based on 2 square feet of wind load and a 20 pound per square foot
wind, which is 70 mph.
So how high above the bracket depends on how big of an antenna you put on it
and what windspeed you want it to blow down at.
73,
Dave, K4TO
> On Oct 24, 2017, at 9:15 AM, Skip via TowerTalk <towertalk@contesting.com>
> wrote:
>
> According to the Rohn catalogue, you can go 35 ft above the bracket. I have
> 40 ft of 25G i used foe my WARC A3WS. Started with a Hygain TH3 till I got
> the big tower up. That was 35 years ago.
>
> Skip, KJ6Y
> 818-522-5421 cell
> Communications Service Co
> Sent from my iPad
>
>> On Oct 23, 2017, at 9:20 PM, Terry Brown <n7tb@comcast.net> wrote:
>>
>> I am trying to determine how high I can use a Rohn is 25g unguyed.
>>
>> Here is my situation:
>>
>> I want to sink a 10 ft section of Rohn 25g into 3 ft of concrete base.
>> This will leave 7 ft. Above the base. I will then attach another 10 ft.
>> Section and attach a house bracket at the 14 ft level. This will leave the
>> second section unguyed for 3 ft above the house bracket. How many more 10
>> ft. sections can I add safely above that point? My antenna will be a Mosely
>> TA33-Jr (27 lbs) wind surface area 5.1 sq. Ft. Windload 98 lbs at 80 mph.
>>
>> Rotor is Alliance HD-73.
>>
>> Thanks!
>>
>> Terry
>>
>>
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