Home >> Hobbies >> Ham Radio

How to Make a 70cm Whip Antenna

Whip antennas are a type of monopole design. These antennae are single-lead designs, using the connected device as the ground plane. Whip antennas are found on cars, portable radios, walkie-talkies and a host of other electronic devices. These 70-centimeter antennas are simple in design, use inexpensive materials and are surprisingly reliable, given their simple construction.

Things You'll Need

Measuring tape
RG-58 coaxial cable
Wire snips
Soldering iron
Lead-free solder
Coaxial strippers
Coaxial "N" connector
Coaxial crimper
80 centimeters of 2 millimeter diameter heat shrink tubing
3 inches of 1/2 inch diameter heat shrink tubing
Heat gun

Instructions

- 1
  Measure and cut a 75-centimeter section of coaxial cable. Strip all but 5 inches from the length of coaxial cable, exposing the copper center conductor.
- 2
  Strip 1 inch of outer insulation from the other end of the coaxial cable. Slide the "N" fitting's compression collar up the cable and temporarily out of the way.
- 3
  Slip the metal tip of the "N" connector over the end of the copper center conductor. Apply a small bead of solder into the hole on one side of the metal tip.
- 4
  Push the "N" connector's body over the end of the cable. Press firmly until the end of the cable seats against the inside collar of the connector. Slip the compression fitting over the smaller collar on the "N" connector. Crimp the connector in place with the coaxial crimp tool.
- 5
  Slip the 2-millimeter shrink tubing over the exposed copper center conductor. Turn the heat gun on its "low" setting. Move the heat gun 3 to 4 inches over the surface of the tubing until it forms snugly over the copper. Applied properly, the excess tubing seals over the tip of the copper.
- 6
  Slide the 1/2-inch diameter heat shrink tubing down the antenna, centering it over the gap between the remaining coaxial outer jacket and the copper center conductor. Heat and form this over the gap to maintain a moisture seal.

Ham Radio