Homemade FM Radio Broadcast Antennas
FM antennas can be made from TV antennas or standard TV wire. They can be used inside by your receiver or hidden out of sight in your attic. A motorized rotor can be used to turn the antenna direction to maximize your signal reception. The antenna can be as simple as a coat hanger used for a pair of "rabbit ears" or as complex as stacked Yagi antennas with a preamp and directional rotor/motor. Look over the field and choose the antenna that best fits your needs and requirements.
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Simple Homemade FM Antennas
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The TV "rabbit ears" can serve as an indoor FM antenna as well. Simply hook it up to your receiver and find an FM station. Slowly rotate the base for best reception. You can also adjust the length of the ears and find the point of maximum or clearest signal reception.
Another old standard is the doublet dipole or "T" FM antenna. It is just a loop of TV antenna wire in the form of a "T." The length across the top of the "T" is 3 feet. You can make the doublet better by constructing a simple X wooden frame and doubling the doublet in two directions 90 degrees apart. 3 feet is about one third of a wavelength at the high end of the FM broadcast band or 108 MHz. A 9 foot "T" across the top would make a better antenna because it represents a full wavelength and would pick up a stronger incoming radio signal for your receiver, i.e. giving you stronger reception. The 3-foot "T" will work just fine in a high signal area where you are fairly close to your transmitting FM station. The smaller antenna is easier to work with and not so obvious as to take a major role in your room's decor. All radio signals will be available at your dipole antenna regardless of length, but its size will pass preferentially those radio signals whose wavelength is the same length or fraction thereof, say half wavelength or a third wavelength, of the dipole's "T" length. The full wave antenna will provide the most gain (stronger signal) in these cases. Other radio signals of different wavelengths may not be strong enough to pass from your dipole especially at an inside location.and be above the detection limit of your receiver.
Antenna survey tests have been run on various FM antenna configurations. The results are included in the References under "No Tux FM Antenna Survey." The rooftop antenna appears to outperform other types. It is a directional Yagi design with multiple directors and reflectors. You can build one like this and other more sophisticated FM Antennas as listed in the next section.
DIY FM Antennas
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FM antenna plans are listed in the References below and cover high-gain J-pole antenna, a circularly polarized antenna, yagis, a tunable dipole, a super 3-pole, and even a tin-can waveguide antenna. Look over the field and see if one or more of these designs fits in your pursuit of your ideal FM antenna.
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