30 MHz - 450 MHz
There are several radio-bands within the range from 30 MHz to 450 MHz reserved for radio communication of the Private Mobile Radio (PMR) networks. These are especially the bands of 40 MHz, 80 MHz, 160 MHz, 400 MHz and 450 MHz. Simplex analog or digital radio networks usually operate on these bands for:
- police force
- health service
- fire brigades
- road maintenance
- auxiliary railway networks
- private company networks
Most of these services use simplex radio stations in 25 kHz, 20 kHz or 12.5 kHz channel spacing.
This technology requires specific solutions to provide radio signal coverage in underground areas and tunnels. Such conditions mostly require covering underground area with coherent signal of several networks of a very small frequency spacing. Amplifiers and filter systems must therefore enable mutually undisturbed two-way simplex connection of several services operating at the same time. For this purpose, RCD Radiokomunikace uses individually designed systems of RF filters using high quality cavity resonators.
