As we all know, the antenna is the most
important part of any transmitter system. It must be placed as high as
possible, properly matched to the transmitter, and designed to
effectively radiate the power applied to it. The antenna that we are
going to construct will be made from ordinary 300-Ohm TV Twin lead wire.
This wire is available at almost every hardware, drug store, and other
stores that carry such items as telephone extension cords.
In the diagram below you will see the
construction details of the antenna.
Now, on to the step by step.
Tools: Ruler, Wire strippers, Wire
Cutters, Soldering Iron.
-
Measure 54" of Twin lead and
mark this spot with some masking tape. Cut the wire about 1 ½
inches longer than this measurement. If this is your first attempt
at building something, you may want to leave 4 " of extra wire
on the piece you are working with. This will allow an additional
attempt of the critical portion of construction.
-
Remove the center insulation from the
bottom 1-inch of twin lead. Strip the insulation off of the bottom
section of twin lead (only the 1 "). Connect the wire together
at this point and solder.
-
From the splice you just made at the
bottom, measure up about 1 " and remove ½ " - ¾ "
of insulation from each conductor. This is where we will be
attaching the coax.
-
From the splice measure up one side
16 ½" . CHECK THE MEASUREMENT TWICE. Cut a gap on this side
about ¼" wide. Be sure to remove the conductive material from
the notch.
-
From the splice, re-measure the total
length to 54 " and trim the top.
-
Attach some coax to the opened area
of the wire about 1 ¼" from the splice. The shield of the coax
MUST connect to the notched side.
-
Attach a suitable connector on the
end of the coax for your transmitter and GO!
Note: The antenna can be hung from
almost anything using some string through a hole in the insulation about
1" from the top.
