Annex 4 - Resolution A.801(19), as amended, annex 4 - Criteria for use when providing a NAVTEX service
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Annex 4 - Resolution A.801(19), as amended, annex 4 - Criteria for use when providing a NAVTEX service

 1 There are two basic areas which must be defined when establishing a NAVTEX service. They are:

  • Coverage area: An area defined by an arc of a circle having a radius from the transmitter calculated according to the method and criteria given in this annex.

  • Service area: A unique and precisely defined sea area, wholly contained within the coverage area, for which MSI is provided from a particular NAVTEX transmitter. It is normally defined by a line which takes full account of local propagation conditions and the character and volume of information and maritime traffic patterns in the region.

2 Governments desiring to provide a NAVTEX service should use the following criteria for calculating the coverage area of the NAVTEX transmitter they intend to install, in order to:

  • determine the most appropriate location for NAVTEX stations having regard to existing or planned stations;

  • avoid interference with existing or planned NAVTEX stations; and

  • establish a service area for promulgation to seafarers.

3 The ground-wave coverage may be determined for each coast station by reference to Recommendation ITU-R PN.368-7 and ITU-R Report P.322footnote for the performance of a system under the following conditions:

Frequency – 518 kHz
Bandwidth – 300 Hz
Propagation – ground wave
Time of day – footnote
Season – *
Transmitter power – †
Antenna efficiency – footnote
RF S/N in 500 Hz bandwidth – 8 dBfootnote
Percentage of time – 90

4. Full coverage of the NAVTEX service area should be verified by field strength measurements.

Parent topic: Annex - Revised NAVTEX Manual 2018 Edition
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