How far does a shortwave radio station transmit?
How far does a shortwave radio station transmit? The general range is tens to hundreds of kilometers. Shortwave radio is a radio communication device with a working wavelength of 100 to 10 meters (frequency of 3 to 30 MHz). Usually consists of transmitter, receiver, antenna, power supply and terminal equipment.
Condition:
Military shortwave radios are classified into portable, vehicle (or shipborne, airborne) and fixed radios according to their purposes and conditions of use. Portable radios are mainly used to ensure the communication of tactical units. They have the characteristics of small size and light weight. They generally use whip antennas and use ground waves for short-range communication. The power is usually several watts to tens of watts. The vehicle-mounted radio is used to form the communication hub of the command post or used for mobile communication. Its power is from tens of watts to several kilowatts. Generally, whip antennas and double antennas are used. Fixed radios are mainly used for strategic communications, usually composed of a central station for sending and receiving. To use ground wave communications, the frequency range of portable and vehicle-mounted radios has been extended to the mid-wave band, typically 1.6 to 30 MHz.
Be applicable:
Shortwave radios are generally used to transmit voice, constant amplitude and frequency shift reports. When transmitting telephone signals, shortwave radios mainly use amplitude modulation and single sideband modulation. Amplitude modulation is to make the amplitude of the high frequency signal vary with the signal being transmitted. The spectrum of AM wave is composed of carrier frequency, upper sideband and lower sideband. The transmitted information is contained in only two sidebands, and each sideband contains the complete transmitted information. If only one sideband is transmitted, it is called single sideband modulation. When transmitting telegraph signals, amplitude keying or frequency shift keying are mainly used.
