[Towertalk] Tree Mounts

[Jon Zaimes AA1K]

Steve,

How long does the tree last after topping? Won't that kill it?

Do you install steps for future access for maintenance? 


How about using a Ring Rotor -- anyone tried this?

I have lots of 80 ft. pines....


73/Jon AA1K

At 08:16 PM 9/6/02 EDT, you wrote:
>In a message dated 9/6/02 5:00:39 PM Pacific Daylight Time, 
>kellyjohnson@telocity.com writes:
>
>> Does anyone out there have any experience with mounting a rotatable yagi
>>  to a tree?  I've been told this is (or used to be) common in the Pacific
>>  Northwest.  I'd be interested in hearing:
>>     1) How to calculate a safe load
>
>    Calculate? How would you come up with a formula for the tree capacity? 
>
>    I've installed 14-15 antennas in trees including HF yagis and 2L 40M 
>beams so I have a professional perspective but don't have any numbers to
show 
>you. 
>
>    I usually top the tree when it's about 10 or so inches in diameter. How 
>strong is an 8x8 piece of wood? Pretty danged strong actually. 
>
>    If you're talking about an HF beam, I wouldn't go any larger than
about a 
>16' or so boom - the forces just get too big.
>
>    The other limiting factor is rotator capacity since I pipe mount the 
>rotator and then the antenna on top of it. I prefer the T2X since it has a 
>lot of mast mounting capacity and will twirl just about anything small to 
>moderate in size for a long time. 
>
>>     2) How to fabricate a suitable mount
>
>    I use a piece of galvanized pipe (1-1/2" ID = 1.9" OD) with a horizontal 
>piece welded to it (picture a cross). The horizontal ends are bolted to the 
>tree as is the vertical pipe. The rotator goes on top of the cross. I use 
>1/2" lag screws on the vertical pipe - 3-4 of them - and screw them right 
>into the tree. The antenna will blow away before the mount fails.
>
>    A BIG advantage for a tree installation is that it's UNREGULATED when it 
>comes to building departments! I charge a lot for them because they're dirty 
>and a lot of work. 
>
>Cheers,
>Steve    K7LXC
>TOWER TECH -
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