Technical requirements for the operation of Personal Radio Service stations - Citizens’ Band (CB)
The operation of Personal Radio Service stations, Citizen’s Band (CB) shall comply with the following technical requirements:
1. Frequency band - the frequency band allocated to the Personal Radio service, Citizen’s Band (CB) is between 26.960 MHz and 27.410 MHz.
2. Permitted frequencies - whichever mode of transmission is used for communication, the centre frequency of the channel shall be selected from the frequencies shown in the table below:
|
1..........26.965 2..........26.975 3..........26.985 4..........27.005 5..........27.015 6..........27.025 7..........27.035 8..........27.055 9..........27.065 10..........27.075 |
11..........27.085 12..........27.105 13..........27.115 14..........27.125 15..........27.135 16..........27.155 17..........27.165 18..........27.175 19..........27.185 20..........27.205 |
21..........27.215 22..........27.225 23..........27.255 24..........27.235 25..........27.245 26..........27.265 27..........27.275 28..........27.285 29..........27.295 30..........27.305 |
31..........27.315 32..........27.325 33..........27.335 34..........27.345 35..........27.355 36..........27.365 37..........27.375 38..........27.385 39..........27.395 40..........27.405 |
2.1 Channel spacing - the spacing between channels shall be 10 kHz.
2.2 Mode of operation - the establishment of alternative communications on the same frequency or channel shall be permitted (single frequency simplex mode).
2.3 Distress, emergency and safety channel - the 27.065 MHz frequency (channel 9) shall only be used to establish distress, emergency and safety communications.
2.4 Call channel - the 27.085 MHz frequency (channel 11) shall only be used for call communications.
2.5 Channels for data and picture transmission (slow scan television) - the frequencies 27.025 (channel 6). 27.035 (channel 7). 27.235 (channel 24) and 27.245 MHz (channel 25), although these channels can still be used for voice communications.
2.6 The occupied bandwidth shall be compatible with a channel width of 10 kHz.
3. Modulation types - the following modulation types shall be permitted
a) Amplitude modulation1;
b) Frequency modulation;
c) Phase modulation.
4. The following transmissions shall be permitted:
a) Voice transmission;
b) Data transmission2;
c) Picture transmission (slow scan television)2.
5. Transmitter power
5.1 Transmitter output power - The power measured at the transmitter output of a CB station shall not exceed:
a) 4 W carrier power in the case of amplitude modulation, double sideband;
b) 12 W peak power in the case of single sideband amplitude modulation with suppressed carrier;
c) 4 W carrier power for angular modulation.
5.2 Effective radiated power (ERP) - The maximum permitted effective radiated power (ERP) shall be 4 W.
1 The use of CB stations operating on amplitude modulation, single sideband with reduced carrier wave (R3E) is prohibited.
2 The levels of unwanted emissions must not exceed those corresponding to voice transmissions.
See also:
- Amendment to the technical requirements for Citizens' Band (CB) personal radio stations operating in the 26.96 - 27.41 MHz frequency band - amendment to the NFAT https://www.anacom.pt/render.jsp?contentId=1771640
