In a message dated 98-04-06 16:00:37 EDT, kn4ab@home.com writes:
<< I just picked up some used Rohn 25 and a 25AG5 top section.
This top section from what I measure is 2.5" id. What size mast is this
top secion made for? If I want to use a 2" mast does anyone sell a
sleeve for it?
Any mast that'll fit through it will work. Don't worry about
sleeving/shimming it. Letting it bang around a little bit won't cause any
significant problems. By sleeving it you'll probably pick up some binding
somewhere as well.
> I am going to bolt this tower with the Rohn base plate to
a concrete slab behind the house. The house is 16 ft high
in the back, so the house bracket will probably be at 15 feet.
I want to put 40 ft and have 3 guys on it at the top. One
guy to the roof and the other two into the backyard.
The antenna is a HY Gain 10/15 mtr beam that only has 4.5 sq ft.
How long a mast can I safely use with?
As long as everything is installed with proper engineering and hardware,
your 40 feet sounds fine.
You can use just about any mast you want. The question is more the
anticipated wind speeds and wind load which is related to length. I'll look up
your county windspeed when I get home.
>Does this seem to be a safe installation considering that I am not setting a
base
into concrete?
Your slab is probably only a couple of inches thick so isn't very robust.
The best way to do it is to get a concrete saw and saw open enough of the slab
to dig down and install a real base.
> I emailed Rohn for a catalog however no response yet. >>
That's what TowerTalk is for. Rohn catalogs are five bucks from TOWER
TECH, Box 572, Woodinville, WA, 98072.
Cheers, Steve K7LXC
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