ISM frequency bands – the 868 MHz frequency range belongs to an unlicensed frequency band, which may be used in the RF without obtaining authorization from the SCRF, provided the requirements for bandwidth, emitted power, and intended use of the finished product are met. The 868 MHz frequency band includes two frequency segments:
868.0—868.2 MHz
868.7—869.2 MHz
The max output power must not exceed 10 mW for 868.0—868.2 MHz and must not exceed 25 mW for 868.7—869.2 MHz.
For applications in network deployment data exchange, wireless control and monitoring systems, the ISM frequency bands frequency range 868 MHz is the most optimal. Compared to the 2.4 GHz microwave band, the longer wavelengths of 868 MHz have lower attenuation intensity, resulting in greater penetration through obstacles and a effective transmission range. For example, a brick wall with a thickness of 89 mm absorbs about 3.5 dB of power at 868 MHz and 6 dB at 2.4 GHz. Also, compared to the 433 MHz band, the 868 MHz frequency is less congested, which contributes to more reliable device operation.
Other unlicensed radio frequency bands: LPD frequencies , PMR frequency grid, CB frequency range.