In a message dated 99-07-23 11:49:39 EDT, cabmas@bankpds.com writes:
> At present I am in the process of stacking 2 KT34XA's on an 80 ft
Rohn 25
> tower.
> One of the beams is fixed at 50' bolted to the side of the tower,and
the
> other is at
> 82' rotateable. There is alot of Rohn 20 tower available in this area
on
> the used
> market and I was just curious as to whether or not a Rohn 20 would be
able
> to
> support this same configuration.My present setup is guyed in 3
places,as
> would
> a Rohn 20 tower if it were a feasible.
The reason there is a lot of Rohn 20G available is that it's TV tower
and many people who had a TV antenna on them are now using cable, DSS, etc.
so there's a lot of it surplussed.
To quote the Rohn book, "The #20 tower is NOT (my emphasis) recommended
for commercial, ham, CB or guyed installations". The problem is that it was
designed for 40 foot maximum free-standing TV antenna loads and doesn't have
the torque resistance of even Rohn 25G.
25G would also would be unsuitable for your proposed installation. You
could put up one XA @ 9 sq.ft. but 25G is only rated at 9.5 sq.ft at 90 MPH.
Putting up a stack of two would have a high probability of failure.
Sauk County is an 85 MPH windspeed zone. Do yourself a favor and get
the Rohn catalog so you can do proper planning in order to avoid an
inevitable disaster like you're proposing. Champion Radio Products has them -
http://www.championradio.com or 888-833-3104.
Cheers, Steve K7LXC
Tower Tech
Champion Radio Products
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