If the tower is only going to be 10' from the property line, then the turning
radius of the HF yagi will produce an "aerial trespass." I would make sure
that the affected neighbor is OK with this. I personally would never do
this. I think in our litigious society that is asking for trouble.
I also have a bracketed Rohn 45 tower; 45' with the bracket @ about 26'. I
used the Rohn HBUTVRO house bracket, which is very nice and very heavy duty.
You could not duplicate the quality of this bracket with 2X4's. I built an
extensive structure in my attic to back-up the tower. I tied the first four
rows or so of engineered trusses together with 2X6's in two places, put
additional 2X6's between them, then bolted 3/4" plywood on top of those.
Right behind the tower bracket, I backed-up the wall with a 2X12 several feet
long (as long as I could stuff through the attic access), then included
Simpson Strong Tie 4X4 hangers on each of the 4 bolts which affix the bracket
to the house. I used 4 more of the Strong Tie hangers on the 3/4 plywood
deck I made, and then used 4X4's to connect the bracket to the deck. I did
all of this to distribute the load to a larger area. Screws and bolts were
used for all connections; no nails. This is a simplistic description of the
structure, but hopefully it gives you an idea of it's "beefy" nature.
My wind loading is not too severe; I have a 12' mast about 6' out of the
tower with a Force 12 C3 just above the tower, and a 11 element 2 M yagi near
the top. A friend has his 19' tall 2M repeater antenna at the very top, and
I have another 11' VHF vertical side mounted at about 30'.
You can't really appreciate how much loading occurs at the bracket until the
wind blows and you hear the rumbling through the house. And it will rumble,
if you did a could job fastening the tower to the house. I would probably
never do a significant bracketed tower again just because of the noise during
a storm.
In spite of the rather massive structure I have in the attic, I get nervous
every time we have a big blow. The proposed structure would absolutely scare
me to death, especially in the 110 mph wind zone. I think it is not a matter
of IF it will fail, but WHEN it will fail. And it will probably take a chunk
of the house with it.
Sorry for the gloomy outlook.....
73,
Ron AD7L
Hillsboro, Oregon
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