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Radio modems

Besides frequency bands, a radio licence specifies the structural requirements for planning and creating fixed radio networks using radio modems. Radio licences for modem networks are granted based on case-specific frequency planning.

The requirements for radio networks using radio modems apply to fixed radio networks subject to a licence, which are used for

  • control applications
  • alarm applications
  • telemetry applications
  • telecommand applications, and
  • data transmission applications

and which operate in the frequency bands listed below.

These radio networks consist exclusively of fixed radio modems or similar radio equipment. The radio networks are placed in the following frequency bands:

146.00625–146.29375 MHz

Channel width 12.5 kHz

161.4125–161.4625 MHz

Channel width 25 kHz (duty cycle < 10%)

406.625–406.925 MHz

Channel width 25.0 kHz

407.0625 MHz

Channel width 100 kHz

407.2625 MHz and 407.4125 MHz

Channel width 150 kHz

409.0125–409.9750 MHz

Channel width 12.5 kHz

419.825 MHz

Channel width 150 kHz

419.950 MHz

Channel width 100 kHz

429.825 MHz

Channel width 150 kHz

429.950 MHz

Channel width 100 kHz

440.90625–441.18125 MHz

Channel width 12.5 kHz

441.200–442.750 MHz

Channel width 25.0 kHz

444.750 MHz and 444.900 MHz

Channel width 150 kHz

446.21875–446.99375 MHz

Channel width 12.5 kHz

448.78125–448.99375 MHz

Channel width 12.5 kHz

449.00625–449.51875 MHz

Channel width 12.5 kHz

468.125–468.175 MHz

Channel width 25.0 kHz

468.225–468.700 MHz

Channel width 25.0 kHz

Traficom assigns the frequencies to be used separately for each network.

Structure of modem networks

In modem networks, the span length may usually not exceed 15 km. Repeater stations are recommended for longer spans or in a difficult terrain. Traficom may order using a repeater station if the efficient use of the frequencies or avoiding interference so requires.

There must be a possibility to adjust the output power of the transmitter and to connect an additional filter to the receiver, if necessary.

Antennas

Directional antennas must be used on slave stations. On central stations and repeaters, a directional antenna must be used if the coverage area allows it.

Traficom may change the antenna requirements on a case-by-case basis if avoiding interference or efficient use of the frequencies so require.

Radio licence application

A licence application must include technical data of each fixed station. The obligatory data for a transmitter include output power (W), frequency band and channel width. For an antenna, the obligatory details include the gain (dBd) or type designation and, possibly, the manufacturer as well as the antenna height above ground level and polarisation. For an antenna cable, the obligatory details are type designation and length or attenuation (dB).

To determine station locations, the licence application must indicate the coordinates for the location of each station antenna (e.g. 332723/6820289) as well as the related coordinate system. Maps on the locations are not obligatory but Traficom may request maps if the indicated coordinates or system are not sufficient.