“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 322 for the performance of a system under the following conditions:

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