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AM antenna vs FM antenna | AM antenna,FM antenna difference

This page compares AM antenna and FM antenna and mentions basic difference between AM antenna and FM antenna. AM antenna is used for AM(Amplitude Modulated) wave and FM antenna is used for FM(Frequency Modulated) wave transmission/reception.

AM stands for Amplitude Modulation while FM stands for Frequency modulation. In this page we will understand basic functions and specifications of antennas used specifically for AM and FM broadcasting and reception.
Refer basic difference between AM,FM and PM.

Antenna couples 2 wire transmission line having impedance of either 50 Ohm or 75 Ohm with air having impedance of 300 Ohm.

AM Antenna

AM antenna

The figure-1 depicts typical AM antenna of loop ty[e used for AM wave transmission and reception. Following are the features of AM radiators or AM antenna systems.
• AM antenna systems are vertically polarized. This helps in better groundwave propagation as well as to have simple antenna design.
• The electrical length of an AM antenna is usually 90 electrical degrees which is about 1/4 of wavelength or more. This length provides adequate bandwidth and efficiency both.

Following are the typical specifications of AM antenna.
• Frequency: 520 kHz to 1700 KHz for Indoor use
• Pattern: Omni-directional
• Polarization: Vertical
• Impedance: Usually 350 Ohm for AM wire antenna, requires balun to match impedance as desired.
• Application: In Analog TV systems to transmit picture/sound

FM Antenna

FM antenna

The figure-2 depicts typical FM antenna used for FM wave transmission and reception. The FM antenna shown is of cross dipole type. FM operated between 88 MHz to 108 MHz frequency band.

Following are the typical specifications of FM antenna.
• Frequency: 88MHz to 108MHz
• Gain:-3dBd
• Impedance: 50 Ohm/75 Ohm
• Polarization: Horizontal
• Input: 500 watts for 50 Ohm case and 100 watts for 75 Ohm case
• Pattern: Omni-directional
• Application: Used for sound transmission in analog radio broadcasting stations.

Antenna related links

Smart Antenna   Antenna Tutorial   Antenna Gain vs Effective Area   Types of antenna   TV Antenna   TV Antenna Booster  Satellite Dish Antenna   Mobile Antenna   Antenna Suppliers   Antenna Installation 

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