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The quagi antenna in my opinion is the perfect
choice if you are looking for a home brew, easy to construct,
high gain, inexpensive 2 meter antenna, or any VHF/UHF
antenna.
Below you will find compleate plans to construct this
antenna. For best results it is imperitive that you cut the
element lenghts exact, or as exact as possable. I like to cut
the wire a little long with wire cutters and then use a
grinder to get it exact.
This antenna can be built in a variety of ways, with up to
100% of the parts salvaged. I doensnt matter at all what type
of materials you use. It will work fine just so the element
are insulated from ground, preferably with material that will
not collect water, such as PVC, bamboo or the like.
Large aluminum power line wire is perfect for the elements.
The strands, although a bit tricky to straighten out are
perfect for VHF/UHF antenna elements.
The boom can be made of any non conductor such as wood,
PVC, fiberglass, etc. Note that PVC will sag over time,
some support on the ends will help this. I usually
choose PVC because it is cheap and readily available. Be
carefull if you paint any antenna, some paints conduct!
The quad elements use #12 wire or equivelent,
supported at the top and bottom by Plexiglas(or any non
conductor). An so 239 or suitable connector is soldered to the
bottom of the driven element and coax connected directly to
it. The driven loop is open at the bottom with the center of
the coax connected to one side and the shield connected to the
other. The reflector is a closed loop.
The directors are welding rod or any stiff wire of about
1/8 inch will do.
Cut the elements as close to the plans as possible, any
slight difference will degrade performance. Do not
expect a flat swr across the band, this antenna is
designed for maximum gain. I usually get a couple of MHz
below 2:1 at 2 meters. A common mistake is to assume
that a wide bandwidth or low swr means that the antenna
will work great, actually it's often the opposite. A low
swr across a wide range can mean low efficiency. A dummy
load has a wide bandwidth but isn't a very good antenna.
This antenna can be mounted horizontal or vertical.
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144.5 |
147 |
| Element lengths |
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| Reflector |
86-5/8 |
85 |
| Driven |
82 |
80 |
| Directors (total of 6) |
35-15/16 to 35
in 3/16 steps |
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| Spacing |
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| R-DE |
21 |
20-1/2 |
| DE-DE1 |
15-3/4 |
15-3/8 |
| D!-D2 |
33 |
32-1/2 |
| D2-D3 |
17-1/2 |
17-1/8 |
| D3-D4 |
26.1 |
25-5/8 |
| D4-D5 |
26.1 |
25-5/8 |
| D5-D6 |
26.1 |
25-5/8 |
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