What are VHF Radios?

Very high frequency (VHF) refers to radio waves with a frequency band from 30Mhz to 300MHz. The frequency lower than the VHF radio frequency is high frequency (HF), and the frequency higher than the VHF radio frequency is ultra high frequency (UHF).

VHF communication system is used in the aviation industry to ensure that the aircraft can communicate with the ground and between the aircraft during the flight. VHF communication systems operate at very high frequency bands. Therefore, they are referred to as VHF communication systems. Compared with VHF communication systems, those that are lower than VHF are called high frequencies and higher than VHF Is called UHF. Due to the high frequency of the VHF communication system, it is often subject to different levels of electromagnetic interference during its operation. The main working form of VHF communication system is based on images, data, and voice. During the work, information and instructions are transmitted to the receiver through radio signals or light. It is applied to the communication network of the aviation industry, which makes it convenient for the aircraft to establish mutual relations with the ground and between the aircraft during the flight.

The VHF communication system adopts the AM working method during the working process. The so-called AM working method refers to that the working frequency is maintained within the range of 117.000 ~ 152.000 MHz during the working process. The interval does not exceed 25 kHz, and its maximum operating frequency floats around 135 MHz. Very high communication systems are used in the aviation industry, and the highest frequency of their work, the frequency range of work, and the interval of each frequency, etc., are all approved by ICAO. Of course, due to the high operating frequency of the VHF communication system, the surface wave attenuation of the VHF communication system is rapid. Whether it is the communication distance or the propagation distance, it will be limited by a certain distance. Therefore, VHF communication systems are currently mainly based on the propagation of space waves, so that during the propagation of space waves, they are greatly affected by terrain, troposphere, and magnetic field interference ^[1]

VHF is mostly used as a radio and television broadcast, and is also a communication channel for aviation and navigation.

1 Increase the distance between the tower and the approach station to avoid electromagnetic interference.

2 Intensify efforts to rectify the environment in which radio stations are used and ensure the implementation of aviation VHF communication systems ^[2] .