Hello George et al,
Excellent questions. I did not consider the tree in my installation as
absorption or degradation of signal. Since I was utilizing 3.5 MHz I figured
the tree was transparent to my antenna and RF. Since I worked DX from all over
the compass I was happy. Some notes on the mechanics and an anecdotal story
follow.
I used a fishing rod and reel to sling up a suitably heavy cheap socket from a
ratchet set over the top of the tree, then removed the socket and attached a
heavier nylon line to the fishing line. To attach fishing line to the nylon I
used a boy scout technique which is difficult to describe verbally but involves
doubling the fishing line wrapping it upon itself and securing the free end in
the loop protruding from under this wrap - this eliminates knots which can snag
on branches) and hoisted the nylon line back over, at this point if a larger
nylon line is desired repeat this process using the smaller nylon to pull the
larger nylon. Finally used the nylon line to pull my wire up over the top.
The nylon line remained in place and was tied off with very low tension to a
suitable springy branch (a screen door spring works well if attaching to solid
tie off) to accommodate wind movement in the tree and remained in place 3 years
with Midwest storms until needing repairs due to abrasion. Proactive nylon
line replacement annually can be accomplished by tying new line to old nylon at
the tie off end and pulling the antenna down removing the old nylon and
securing the new line to the antenna tip end and pulling it back into place.
This eliminates further tree fishing technique. Wire was insulated single
strand solid household electrical wire.
I was not concerned if some of the wire was not completely vertical, and the
mid section of the wire did come out away from the trunk through certain lower
branches. The bottom end of the wire then approached the trunk again (the
whole vertical wire forming a lazy C) to the base insulator which was attached
to the trunk using a deck screw into the trunk and was almost at ground level.
The coax center attached to the wire going up into the tree, the braid to my
ground radials laid random length as space provided on the ground in garden and
not visible areas and buried in foot traffic and visible areas. Further, I
bonded all neighborhood chain link fences with aluminum brazing rods available
for use with a propane torch and attached the ground system to these fences as
well.
Using an MFJ analyzer I was able to resonate the wire easily by pruning the
wire at the base, (if multiple wire verticals are in the near field be sure to
ground them out when taking resonance measurements on the antenna of interest).
I had made sure the overall wire was longer than needed to start with and
could loosen the nylon line tie off and allow the wire to be pulled at the
insulator to cut off a few inches off the vertical wire at a time.
An anecdotal comment: I tried to sling a heavy 19mm (metric since working on
metric 75/80M radio waves) socket over the top of the tree with lighter weight
nylon line attached to the socket. I attempted this bolo style. Well as Mr.
Murphy would have it, the socket and nylon caught a branch on the way up at the
35 foot level and swung around the offending branch several times and locked
itself onto the branch at a fork in the branch. Repeated yanking yielded no
loosening of this predicament. I decided to put my weight into it. So I
wrapped the nylon line around my substantial rear end and attempted to walk
backwards to free the line and the socket from the branch with brute force. I
believe it was 5 or 6 steps backwards and the line was taught as piano wire
when the branch snapped and freed the socket and line. What I saw next was a
19mm socket rocketing toward me at hypervelocity. I was unable to avoid the
inevitable collision with my upper chest! It stung and I was glad it missed my
head and thought all was well, after all, I had my line and socket back for
another attempt. Sad to say a few minutes later I noticed my stomach felt wet
and looked down to see a rather large area of blood stained shirt. The impact
of the socket on my upper sternum had opened a 3 inch wound down to the bone
which required sutures to repair. The physician was amused by my tale of being
shot with a 19mm socket whilst tree fishing for maple bass. It took quite a
few stitches to repair the wound, I am still repairing my ego!
KB0GU
|