Radio modems and frequencies of fixed networks using 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.