[TowerTalk] Anchor bolts for LM470

[K0DAN]

IMHO buying a new factory base is the right thing to do. Following the 
manufacture's specs may cost more, but will give you peace of mind when the 
big winds blow, the codes enforcement and insurance people are on hand, and 
when you worry about the safety of your family, antennas, cables, hardware, 
etc.

If you decide to roll your own, by all means make sure you can pass any 
codes/zoning/inspection requirements for safety, liability, and future 
transfer of title. If you're out in the county where you can roll your own, 
be sure you have a massive steel/rebar structure deeply embedded in the 
concrete to secure to the tower. Don't not just rely on some bolts to hold 
this massive structure in place. Make no mistake, this is a big and heavy 
tower (it's great!!!) but it has some major forces working on the base. I'm 
sure it is comparable to similar 70+ foot self-supporters of similar design, 
but I have no knowledge of them.

The LM470 requires around 9 yards of concrete (I'm doing this from memory, 
please consult the spec sheet!), to which your tower base must be bonded. To 
have any confidence in all that steel, coax cable, and aluminum wind load, 
you need this self-supporting tower to be part of the deep/heavy concrete 
footings. If you are in an area which requires a building inspector or M.E. 
or certify your installation you can be sure you'll need to follow the 
factory specs. Why try to shortcut anyway? If you're investing several 
thousand in the tower, several thousand in the concrete and installation, 
plus several thousand in antennas, cables, rotors, etc., what's the 
difference of a few hundred to buy the proper foundation cage for the 
footings, and put it up correctly, pass the code inspections, and have peace 
of mind when the 70 MPH winds and 1" ice loading clobber your tower?

Perhaps anchor bolts will work with an alternate base, but they are not 
certified by the manufacturer. Do you need engineering certification? Where 
& how do you obtain it?

With all due respect, good luck, and 73,

dan
k0dan

-----Original Message----- 
From: Dave Hachadorian
Sent: April 15, 2012 09:29 PM
To: Towertalk reflector
Subject: Re: [TowerTalk] Anchor bolts for LM470

So how are you guys using anchor bolts on an LM470?  Has someone
designed an LM470 mounting plate that fits on anchor bolts?

Normally the LM470 mounts on a special base section that is
buried in concrete.  If you want to move the tower, you have to
buy another base section from the factory.  What are you guys
talking about?

Dave Hachadorian, K6LL
Yuma, Arizona

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