CB - radio
Citizen Band in the 27 MHz - range
CB radios work in the upper shortwave range at approx. 27 MHz. The radio frequencies are therefore in the 11-meter band and are on the borderline between short and ultra-short waves. The CB frequencies are largely harmonized across Europe according to the CEPT standard.
In most countries there are 40 channels available for operation in AM, FM (4 watts) and SSB (12 watts).
Almost all devices on the market can be switched between amplitude modulation (AM) or frequency modulation (FM). Devices with SSB technology have a greater range, but the voice quality suffers somewhat as a result (Mickey Mouse effect). The operation of SSB devices is somewhat more cumbersome compared to the otherwise simple operation of such devices.
With CB radio, under optimal conditions, compared to other free radio systems, the farthest can be transmitted. Connections over 50 kilometers are possible in CB radio between home stations. Mainly in summer it can come to overreaches, where suddenly distant stations can be received. Conversely, your own station then comes far beyond the usual distance.
CB radios are widespread and the range of used devices is correspondingly large. Handheld radios are usually offered with a built-in antenna, whereas mobile and fixed stations are intended for connection to an external antenna. If you want to increase the range, a more profitable antenna or a downstream power amplifier is usually used (not allowed). CB radio is ideal for communication between vehicles and is therefore often used by truck drivers. There are areas where emergency channel 9 is monitored.
The range of CB handheld radios is often below that of PMR devices due to the poor antenna efficiency. Digital technology has not yet found its way into CB radio.