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How to Build an FM Antenna for a Radio

Updated February 21, 2017

Listening to your favourite FM radio tunes while working or relaxing helps the day go by so much more smoothly. Many times, a distant location or having an interior apartment can make it difficult to tune in or get clear reception on your radio. Following a few basic steps will help you to design an inexpensive antenna that you can mount anywhere and help pull in those hard-to-hear broadcasts in your local or surrounding area.

Calculate the length needed for the horizontal length of the antenna by using the following formula:

93.75 / frequency in mhz = length needed for horizontal measurement (in meters)

Note: 93.75 is a constant in the formula.

Example: 93.75 divided by 95 mhz = .9868 or 98.68 centimetres (or 38.85 inches) To convert centimetres to inches, multiply the centimetres by 0.3937

(Refer to the Resource link below for a quick conversion calculator.)

Note: 95 mhz was selected as the near centre frequency on the FM dial. If you are targeting a specific frequency, simply substitute that in the formula as the "frequency in mhz".

Measure and cut a length of the twin lead wire to 38.5 inches (or the appropriate length if you did not use 95 mhz in the calculation).

Strip the ends off each of the two wires on each end. Twist the two wires from one end together and twist the wires from the other end together.

Measure directly to the centre of the twin lead wire used in Step 2 and 3. Cut one of the wires in the centre. Cut away about two inches of insulation.

Measure the distance between where the antenna will be mounted and the radio. Cut a length of the twin wire to match. Strip the insulation off each of the two wires at each end.

Take one end of the wire from Step 5 and twist one wire to one of the wires in the centre of the horizontal wire mentioned in Step 4. Twist the second wire from vertical wire to the remaining horizontal wire. The antenna should now form the shape of a T.

Mount the horizontal part of the antenna in a horizontal fashion as high as possible for your situation.

Connect the remaining end of the vertical wire to the rear of your stereo. Follow the specific directions for your particular model in the users manual.

Tip

This antenna works great mounted in the attic or a nearby closet.

Warning

Avoid mounting this or any antenna next to power lines, as this could result in serious injury or electrocution.

Things You'll Need

  • Calculator
  • Length of 300 Ohm twin lead wire (15-20 ft.)
  • Measuring tape
  • Wire cutter/strippers
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About the Author

Billy Brainard graduated with a Bachelor of Science degree in education from Trinity College. As the department chairman he was responsible for creating and writing the curriculum for 7-12 grade students. Currently he writes for eHow and works part time helping employees by creating and writing resumes to help in their job search.