In a message dated 6/5/2009 5:18:01 P.M. Central Daylight Time,
towertalk-request@contesting.com writes:
> I asked a colleague who builds a lot of commercial two-way
installations where I could find 2-inch hot-dipped galvanized mast
material locally. He suggested that I use 1.5-inch rigid steel
conduit. I'll be using a 10 ft length with a 3-element SteppIR (no
30/40M element), with roughly 3 ft inside the top section of the
tower. The tower is in a relatively protected location, so not a lot
of wind speed.
So how much exposed mast will you have below the antenna (top of tower
to antenna spacing)?
> I would question whether this is sufficiently robust for a bigger
antenna, but this is not a lot of load. Any thoughts on this?
The proposed material is really 1.9" OD, which is a little skewed
from normal 2" OD ham equipment but probably not enough to be fatal. The
SteppIR mast clamps are a really tight fit on 2" tubing so I imagine there
will still be a sufficient fit for a reliable albeit slightly smaller
installation. A 3L SteppIR is a relatively small load so given your proposed
installation, it'll probably be fine.
Cheers,
Steve K7LXC
TOWER TECH
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