In a message dated 99-09-02 12:28:56 EDT, w9ol@dataflo.net writes:
> I have an older Wilson 60 foot rotatable.
> I'm planning on doing it's yearly maintenance and thought about a better
> mast.
> It will accept a 2" od mast.
>
> I have a vhf GP and a TA53M on this tower.
>
> I know chrome moly may be the strongest mast material but what other
> alternatives would be more than sufficient.
> I plan to have the mast stick out of the tower about 10 feet.
The first thing you need to know when you start talking about masts (or
tower construction planning) is the windspeed rating for your county. You can
find out at http://www.championradio.com under Tech Notes. Cook County is a
75 MPH windspeed zone but there are places (probably near the lake) where it
could be higher. 70 MPH is the lowest rating they give so the windspeed isn't
a major factor.
What is the proposed configuration on the mast? Spacing? If you're
going to have the 2M gp at the top of the mast and the TA-53 right above the
top of the tower, just about anything will suffice - even the 'dreaded'
Schedule 40 water pipe or (dare I say it) aluminum mast.
If you *really* want to know what the bending moment and recommended
mast material should be, you can use the MARC (Mast, Antenna & Rotator
Calculator) Program. It's available from Champion Radio Products for a
pittance.
4130 chromoly is ONLY required for aggressive, large stacked array
systems or where you have high windspeeds. You have neither.
Cheers, Steve K7LXC
Champion Radio Products
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