An antenna built for receiving FM broadcasts should be tuned to receive signals in the 88 to 107 MHz range, the frequencies at which FM broadcasts are transmitted. Here's how to design an antenna, technically known as a "folded dipole," that will provide excellent reception of FM broadcasts.
Cut a piece of 300-ohm twin lead to measure 4 feet 6 inches. Strip both ends of the wire so that each lead has 1 inch of bare wire exposed. Twist these wires together at each end and solder them together.
Make a cut in one of the wire leads at the centre of the cable. Strip back the insulation from either side of the cut so that 1 inch of bare wire is exposed.
Staple the cable to the 5-foot piece of 1-by-2 inch board. Center the cable on the wide side of the board.
Attach the wood screws on top of metal washers at the position of the centre cut. Separate them by half an inch. Position the leads from the centre cut, one to each screw, along with the tabs from your 300-to-75-ohm transformer. Tighten the screws and solder them together.
Screw your RG-6 cable into the transformer and run the cable to the antenna input of your receiver. Screw the cable into the receiver. Turn on the receiver and move the antenna in different positions to test reception.
Things you need
- 1 piece of lumber measuring 1-inch-by-2 inches-by-5-feet
- 300-ohm twin-lead cable
- 75-ohm RG-6 cable with F-type connectors at each end
- 300-to-75 ohm cable adaptor
- Staple gun
- Wire cutters
- Soldering iron
- Wood screws