In a message dated 3/26/2008 9:02:13 A.M. Pacific Daylight Time,
towertalk-request@contesting.com writes:
> On my 1 acre lot, between the "front yard," the house and driveway, and
two
towers,
I'm kinda outta room for more towers, but I do have lots of "vacant" trees
near the property perimeter.
> Please share your success stories with how to mount a yagi on the trunk
of a
tree. I'm
looking to probably fix these in one direction, so no rotation need be
accommodated.
> The main thing is how to attach the boom of the yagi to the trunk of the
tree. If you have
any photos, I'd love to see them. If you've got a "tram" type system,
well,
I'd REALLY like
to see that!
Hiya, Doug --
To rotate a yagi in a tree, you'll need to top it. I don't know if
you'll have to do that if they're fixed. If it's topped, it is easier to
install
since you have more open space for antenna maneuvering and installing.
I use a piece of 1.5" galvanized water pipe (1.9" OD) about 4-5 feet
long when mounting an antenna above the top of a topped tree. Weld a flat
horizontal piece near the top so it looks like a cross. The horizontal piece
keeps
the mast from torquing back and forth. Bend the flat piece so it touches the
tree. There should be a foot or so above the flat piece that extends above
the top of the tree.
Drill a hole in each end of the flat piece along with 3-4 holes in the
pipe. Use 1/2" lag screws to attach the pipe to the tree. While normally at
this point I'd install a rotator (why don't you do that?) in a mast-mounted
configuration, feel free to bolt the antenna to the naked pipe.
You need to use a tramline to get the antenna up there. There has to be
a clear alley from the ground launch point to the mast at the top of the tree
so you'll probably need to do some pruning to clear the branches.
The key - besides the tramline - is the tagline. Tie it to the middle of
the boom (so you can untie it when you're done) and then wrap it around the
element closest to the middle of the boom 3-4 times and then tape it loosely
towards the end of the element. Choose a spot where you can pull down on the
tagline without causing any damage to the element. What you need to do is to
pull the elements almost vertical as the antenna reaches the branches. That
way the elements will miss the branches and when you let go of the tagline as
the antenna arrives at the top of the tree, the antenna will level itself
horizontally above the limbs. When the antenna arrives, untie the tagline and
have someone on the ground pull it thru the tape. It's easy and it works every
time. (BTW as you're preparing the treetop, leave as many branches as you
can as high as you can. Feel free to do enough pruning to get the antenna
installed but if you trim too many branches at the top, there won't be any sap
drawn up to the top of the tree and it'll die at the top and start rotting.)
I use big nails into the trunk for coax attachments. I use tie wraps to
attach the cables to the nails. Don't put anything around branches - that'll
kill them.
Antennas in trees work like a bomb since there is no metallic
interaction - the antennas are electrically floating in space!
Cheers & GL,
Steve K7LXC
TOWER TECH
**************Create a Home Theater Like the Pros. Watch the video on AOL
Home.
(http://home.aol.com/diy/home-improvement-eric-stromer?video=15&ncid=aolhom00030000000001)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|