100MHz

100 megahertz (100 MHz) is a unit of frequency equal to 100,000,000 cycles per second. It lies in the Very High Frequency (VHF) portion of the radio spectrum, roughly between 30 and 300 MHz. The corresponding wavelength is about 3 meters (c/f ≈ 3.0 m), and radio waves at this frequency propagate mainly by line of sight, with some reflection from terrain and objects and limited atmospheric refraction.

In many regions, 100 MHz lies within the FM broadcast band, which runs from about 88 to 108 MHz. Broadcast stations are commonly spaced at 0.2 MHz steps, and allocations are defined by national regulators. The exact use of 100 MHz can vary by country, with licenses granted for licensed services or unlicensed use where allowed.

Technical and practical aspects: Antennas for 100 MHz are relatively compact by broadcast standards; a quarter-wavelength radiator is about 0.75 meters tall. The frequency supports wideband audio in FM modulation, and is also used for point-to-point and mobile communications, telemetry, and data links where allocated by regulators.

Regulation: As with other radio frequencies, use of 100 MHz requires authorization from national communications authorities. International coordination is governed by the ITU and regional agreements to minimize interference among services. The frequency serves as a typical example of the VHF range that enables local and regional wireless communications.