frequency
range of electromagnetic waves used for wireless communication in devices like radios, TVs and mobile phones
frequency: how often a wave repeats per second
Frequency measures how many complete cycles of a wave occur in one second, expressed in hertz (Hz). In industrial radio and wireless systems, frequency determines which band of the electromagnetic spectrum a transmitter or receiver operates on. A 2.4 GHz device completes 2.4 billion cycles every second. The frequency band assigned to a device constrains both its range and its data capacity; lower frequencies penetrate walls and travel farther, while higher frequencies allow faster data rates but need clearer line of sight.
Industrial wireless equipment is rigidly locked to specific frequency allocations set by national regulators such as the FCC in North America or OFCOM in the UK. A factory floor might use 900 MHz for telemetry, 2.4 GHz for Wi-Fi, and 5.8 GHz for point-to-point video links, each serving different purposes. Interference occurs when multiple devices transmit on the same frequency in the same area; this is why licensed frequency bands cost money and unlicensed bands (ISM bands) are crowded and unreliable for mission-critical work.
Frequency drift is a common failure mode: aging oscillators in transmitters and receivers lose calibration and shift their operating frequency away from the nominal value. A radio certified at 868 MHz may drift to 869 MHz after months of use, causing it to fail interoperability tests or lose signal lock with a fixed receiver. Temperature swings in industrial environments accelerate this drift; crystal oscillators are temperature-compensated (TCXO) or oven-stabilized (OCXO) precisely to hold frequency tight.
The term itself comes from the Latin frequentia, meaning repetition or occurrence. In radio work, frequency and wavelength are inversely related (wavelength = speed of light divided by frequency), which is why 900 MHz devices use shorter antennas than 433 MHz ones. The frequency you select for a wireless sensor network or a remote control system is not a performance knob you can turn; it is a regulatory boundary and an engineering constraint set at design time.