Tom Horton wrote:
> I am very sure this has been done several if not many times...but...
> How much cement do I really need to install my 40 foot Rohn 25 with a two
> element Cubex quad and make it freestanding.
>
The ROHN catalog is on-line ( http://www.rohnnet.com/25g-series )and
contains all the information you need, which is going to take a bit more
than you've planned. According to my own catalog the 25 is not self
supporting at any height and in a practical sense, a tower that is
normally guyed takes a lot more concrete at the base if self supporting.
A 25G doesn't take a lot in the way of guys at 40 feet and it's well
worth the extra cost for peace of mind. Were it me, I'd use Phillystran
guys down to about 8 or 10' above the ground and then Galvanized wire
rope or EHS from there to the anchors. ROHN recommends 3/16" EHS for 40'
of 25G
As a side note, I had a 40' supporting a KLM 5L 20 meter monobander with
a 40' boom. It used a "dirt base". Yes it was guyed well. I also had a
40 footer holding a 7L 10 meter Yagi on a 39' boom (guyed with a dirt
base) and a 6L 15 meter with a 40' boom (same set up) The 20 meter and
10 meter setups survived wind and ice that our power line didn't. (the
15 meter set up wasn't in place yet) It was close to two weeks before
we had power. Over half a mile of power line just "tipped over". This
was way out in the country with no zoning and about 45 years ago when
we didn't even think about engineering practices and insurance wasn't a
problem. I'd not recommend this now, although I do still use the
occasional dirt base as I've mentioned before.
73
Roger (K8RI)
> I have a 3x3x3 foot hole, but I seriously doubt that it needs to be full...
> or does it?
> Thanks
> Tom K5IID
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