Phantmi
5/8 Wave or 5/8 Colinear
2 Meter Antenna

Here is an easy to build and rather weather proof 2 meter amateur radio antenna.

The most important formula: x =300/fMhz
(x is expressed in meters here - to get inches multply by
39.37") that a Homebrew Amateur Antenna Constructor
could ever learn.

x"=(300*39.37*.625*.95)/fMhz
x"=7012.78125/fMhz

x"=49.386" for 142 Mhz
x"=48.7" for 144 Mhz
x"=48.033" for 146 Mhz
x"=47.384" for 148 Mhz
x"=46.752" for 150 Mhz

x" x 1/2" dia. rigid copper pipe.
3/4" PVC pipe encases the whole antenna.

20" Encased Coil - 70-74 turns wound on a 1/4" dia.
wooden or simular material pole. #14 gauge solid
copper wire no insulation. Solder each end to the
inside of its respective copper pipe.

Feed Coil - Is 2" long and consists of 4 turns of #14 gauge
bare copper wire wound on outside of 3/4" PVC
encasement pipe. The upper end of which attaches to x"
rigid copper pipe. thru 6-32x1 1/2" screw which is put
thru 3/4" PVC and 1/2" x x" rigid copper pipe (hole
slightly smaller than clearance this allows you to thread hole
with 6-32x1 1/2" screw to make electrical contact). The
lower end attaches to 6-32x1 1/2" screw which passes
thru 1" x 36" aluminium pipe, 3/4" PVC encasement pipe,
and 1/2" x 39" PVC filler pipe.

Coax attachment - Braid attaches to 6-32x1 1/2" screw at
base of feed coil. Center of coax is soldered to second
turn up from base of feed coil or center of 4 turn coil.

Base consists of 1/2"x39" PVC filler pipe inside of 3/4"
encasement PVC outside of which is 1"x36" aluminium
groundplane pipe.

1 piece 3/8"x72" solid aluminium rod used for radials.
Divide it into 3 - 24" pieces bend each piece so it look
like diagram below.

Slip the 4" portion of each into the 2- 1 1/2" hose
clamps shown on the 1"x36" aluminium pipe on the bottom
of the antenna the radials should be slid up as close
to the matching coil as possible without touching same.
Tighten hose clamps spread out the radials equal distance
around 1" aluminium pipe roughly 120°.

Mounting can be done in two ways simply slip base of
antenna into 1 1/4" mast mounted in tripod or at top of
tower or use 1/4" thick 8"x4" aluminium plate and 4
U-clamps 2- 1 3/8" and 2- 1 1/2" drillled thru it.
2- 1 3/8" U-clamps hold aluminium plate to antenna.
2- 1 1/2" U-clamps hold aluminium palte to mast.

Secure coax to mast with electrical tape.
Open coax end, 2- 6-32x1 1/2" screws, and 4 turn x 2"
coil are all encased in clear RTV sealant.(silicon sealant)

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