Homemade 75 Ohm FM Antenna

If you have an FM receiver with a jack for an external antenna, you'll note that the jack is usually specified for 75-ohm antennas. If you're unfamiliar with an antenna design, building an antenna that will work at a specific resistance may seem like a difficult task. But it actually isn't--you can build an antenna that works with a 75-ohm input fairly easily and inexpensively.

Step

Cut a 30-inch length of 300-ohm twin lead cable. Don't be concerned that the cable is a 300-ohm cable and you're making a 75-ohm cable. The cable is merely used as the active element that receives the signal.

Step

Remove 1/2 inch of insulation from the both ends of the cable. Twist together the separate leads at each end of the cable.

Step

In the middle of the cable, cut one of the two elements of the cable and remove 1/2 inch of insulation from either side of the cut with your wire strippers.

Step

Solder each bare wire from the middle cut to one of the tabs of a 300- to 75-ohm transformer.

Step

Connect one end of the coaxial cable to the transformer by plugging it in.

Step

Connect the other end of the coaxial cable to the antenna input of your receiver.