[Towertalk] yagis in trees

[RICHARD BOYD]

Hi, folks.  I've read all the posts on this topic and have a few things to 
add.

1.  A buddy of mine, WY3A (then WA3GZM) hung his TH-3 using three wires (guy 
cable) from trees back in about '68, in Rockville, MD.  I think it worked 
fine but did hop around a lot during wind!  Having three wires kept it 
pretty stationary most of the time.  With just two it would be able to swing 
side to side a lot.

2.  As several have said, the rotator doesn't need to be upside down.  If 
you mount one side immobilized the other side will turn.  (E.g. we usually 
immobilize the bottom whether on a pipe or a plate, and leave the top free 
to turn.  If you immobilize the top, as in a lashup suspended between trees 
and the bottom un-immobilized, the bottom will turn.  With a pipe on the 
bottom and the yagi bolted to the pipe under the rotator, it should turn.  
Will the readout on the indicator box be accurate then or opposite?  Can't 
remember and don't want to strain my brain.

3.  A local tower/antenna installer showed me a homebrew lashup on a 
telephone pole.  A heavy duty piece of welding work, this ham, now deceased, 
had fabricated a ring of steel that went 360 degrees around a telephone 
pole, with a bracket to mount the rotator on.  Actually, it may have been 
two rings several feet apart but welded together with steel angle.  It 
apparently did the job very well but may have been overkill.

4.  Telrex used to sell their "telephone pole lashup" which sounds a lot 
like one other poster described -- two pairs of L-shaped steel angle, with 
welded-on diagonal brace on each -- supplied with all thread rod -- as I 
recall it was somewhere in the 3/4" to 1" diameter, reasonably husky, and a 
rotator plate and a thrust bearing plate to mount onto the two pairs of 
steel angles.  The installer/owner had to drill their own holes in the 
plates and steel angles, since the supplier wouldn't know what diameter tree 
would be used.  They sold for $175 for the set.   If you have or can get 
hold of old Telrex literature you will see a diagram of the whole thing that 
should make cloning of it pretty easy.

5.  Some years ago when I was having some tree work done (clearing some big 
tulip poplars that threatened the house) I decided to have several trees, in 
strategic locations, topped to put antennas on.  Two were tulip poplars and 
one was an oak.  A consideration in which ones I chose was a maximum amount 
of straight trunk -- and height of course.  They were all topped at about 
the 70' level.  To my surprise, the oak died and became, in my opinion, 
unsafe to climb, within a couple or three years.  One of the tulip poplars 
did the same but probably not quite as quickly.  One of the tulip poplars 
put out lots of suckers and branches and appears healthy to this day, some 
12 or 15 years later.  I had the above-mentioned Telrex telephone pole 
mounts on the oak and the tulip poplar that lived.  I had a 2-el 40M quad in 
the tulip polar and it worked great.  I had measured the space around that 
tree, etc. to be sure there was room for the quad.  I misjudged the amount 
that trees move in the wind and the outward space taken up by upper branches 
of trees -- anyway, eventually the quad hung up in the upper small branches 
of a neighboring tree and no amount of "horsing" it could free it and a quad 
arm broke, etc. and that was the end of that.  Eventually the two dead trees 
did fall over, harmlessly during storms.

6.  The advantage of using TIC Ringrotators would be that you could rotate 
antennas not just at the top but others sidemounted lower down.  I think one 
of these more standard ideas for the top antenna would be easier and lower 
cost.  For lower ones the TIC wouldn't be a bad idea..."All it takes is 
money."

7.  Speaking of which...by the time you go to all this trouble to rig up 
something in a tree...you should go back to square one and seriously 
consider putting up a simple tower like Rohn 25 or 45 instead.  "In the big 
picture," at least if you stick to something at the small end like Rohn 25, 
tower is pretty cheap, really, and then things are more standard -- standard 
off the shelf parts and accessories, you can climb the whole thing the 
normal way, mount antennas at the top and sides the normal way, etc.  And, 
at 100' or less, the height range of most of the trees I've seen discussed, 
Rohn 25 will handle most HF yagis.  Someone suggested limiting yourself to 
16' boom on a tree -- well, Rohn 25 should handle that easily, and ones 
considerably bigger than that I reckon.  Maybe AA1K has XYL limits or 
something on actual towers, and maybe his tree lashup didn't take him more 
than a few minutes, but... a 20 or 30 or 40' Rohn 11, Rohn 20, Rohn 25 (11 
and 20 are old ones but still around used and sufficient for small things) 
etc. would be awfully easy to put up.  Though I haven't seen it, I've heard 
stories of W0AIH's 50 (or however many) tower station in Wisconsin and would 
guess that may be the approach he's used...easy to put up another small 
tower when the urge hits you.

8.  One last comment on trees...the tallest ones I've had here in Maryland 
are tulip poplars.  I suspect it's among the tallest species in this region, 
if not the tallest.  Mine are about 120'.  Another local, K3HQ (used to be 
confused with my call a lot when he was KE3HQ and still is some), has ones 
that are much taller than mine.  I estimate them to be 150' and see in a 
tree book that that's said to be their mature height.  Unfortunately, they 
can be more brittle than some other species, maybe not have very deep root 
systems, etc.  And, they shed their lower branches, part of their grow tall 
and straight characteristic, and leave a lot of litter in your yard, do a 
lot of damage to cars parked underneath them (!), and may fall over and 
crush your house someday.  My wife and I were pleased to find a new QTH with 
all the trees in hedgerows and not overhanging the house.

Rich Boyd


KE3Q/W3AO


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