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INTRODUCING OPAR- The One Person Antenna Raiser
by John Reisenauer,
Jr., KL7JR
Like to operate portable? Do you have trouble finding
help for antenna raising at your QTH? This may just be the answer for
you.
You can drive a vehicle on the base for portable operations or
mount permanently at your QTH by bolting base to concrete inserts. Slip
the mast in the base of OPAR (short pipe section tilts), mount your
antenna and hoist up all alone. Mast easily secures in place with moveable
locking bolt and large spanner nut. Guying methods should also be employed
for heavier antennas. I've used OPAR to lift small beams, verticals, rigid
dipoles and various wire antennas to heights of 20-30 feet with minimal
effort all by myself!
 OPAR shown above set up ready to accept antenna
mast. Simply insert mast end in to OPAR pipe stub, install antenna and
raise.
 OPAR shown above with antenna raised
and mast locked in place.
Although OPAR is designed for "one-person operation" using small to
medium sized antennas, it's always good safety practice to have help on
hand. OPAR as pictured is considered "medium-duty" use. Several variations
(use your imagination for your own particular use!) exist (ie-length of
vertical or horizontal members, etc.) depending on your specific use. A
flexible design is what makes OPAR more "user friendly" compared to the
commercially made models. For larger antennas or operating in the Arctic,
I'd recommend adding a second vertical brace higher up on the vertical
section and adding at least another 12 inches or more to the overall
height (36 to 48 inches plus). If you are not an experienced welder, it's
best to have a professional welder do the welding (the number of "good
welds" is directly proportional to the length of time the antenna and mast
stays in the air!). My OPAR cost about $340 to make locally. Raising a
tri-bander alone is not easy especially for the inexperienced Ham, but it
is possible if done correctly. Remember to have help on hand if at all
possible. I wished I had OPAR many years ago! Good luck with your antenna
projects.
MATERIALS LIST (medium duty
OPAR)
- vertical
support 36 inches tall by 9 inches wide w/support braces every 6 to 8
inches.
- horizontal support (drive-on) same as above.
- 1
inch OD square tube steel used (approx. 20 feet total required) for
strength vs. round stock.
- 1/2 inch x 3 inch long bolt with welded
spanner nut
- mast hinge is ½" pipe by 6 inches long inside two ¾'
pipe sections.
- 3/8 inch by 2" wide plate used to secure mast to
top of vertical support.
Some economical mast materials used by KL7JR:
1. Light-duty use: Chain link fence "top
rail" pipe or EMTconduit for smaller light weight antennas.
2.
Medium to Heavy-duty use: IMC threaded conduit
or galvanized threaded water pipe (1 ¼" size works great).
DISCLAIMER Feel free to copy or modify this design at
your own risk. Neither USI, NCDXA nor KL7JR claim any
responsibility.
73 de Yukon John,
KL7JR
KL7JR@arrl.net John
Reisenauer, Jr. PO Box 4001 West Richland, WA
99353
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