VHF air band refers to the spectrum of radio frequencies used for civil aviation communication. The amateur radio hobbyist can tune to the 108 to 136MHz frequencies to listen to a range of air traffic communication. A VHF antenna designed to resonate with the air band frequencies is necessary to receive these signals. Build an inexpensive air band antenna with parts from your local electronic store and listen to your local air traffic communication.
Strip the end of the twin-lead wire, exposing 1/2 inch of wire on each side. Solder the exposed wires together. This will be the bottom point of the antenna.
Measure from the solder point, and cut the twin-lead cable to 61 11/16 inches long.
Measure 20 9/16 inches from the solder point, and cut a 1/4-inch gap in the right twin-lead wire. Cut both the insulation and the wire.
Measure 1 1/4 inches from the solder point, and strip a 1/4-inch segment of insulation from both wires. Take care in keeping the wires intact. The feed line will be soldered to these segments.
Strip 1/2 inch of outer insulation from the coaxial cable end. Slice down the side of the braided sheath, and twist the braid into a wire. Remove 1/4 inch of plastic insulation from the tip of the inner copper wire.
Solder the coaxial twisted braid to the exposed wire segment on the right side of the twin-lead, below the 1/4-inch gap. Solder the copper wire to the exposed wire segment on the left side of the twin-lead. Wrap electrical tape around the coaxial cable and twin-lead to protect these solder points.
Crimp a connector to the free end of the coaxial cable that will fit the external antenna jack on your air band VHF receiver.
Cut a small hole in the insulation at the top of the antenna, and thread a piece of twine through the hole. Hang the antenna from this twine.
Encase the antenna in PVC tubing to weatherproof it.
Tips and warnings
- Encase the antenna in PVC tubing to weatherproof it.
Things you need
- Twin-lead cable, 300-ohm, 65 inches
- Coaxial cable, 50-ohm, 10 feet
- Soldering iron and solder
- Utility knife
- Wire stripping tool
- Coaxial crimping tool
- Measuring tape
- Electrical tape