June 1999 | NTIA Technical Report TR-99-364

Lower Mississippi River VTS Frequency Survey

Robert L. Sole; Brent L. Bedford


The maritime mobile frequency band supports maritime communications worldwide. Appendix 18 of the ITU Radio Regulations (RR) defines the channels of the maritime mobile service. These channels support a variety of communication functions including: public correspondence, intership and ship-to-coast, coast- to-ship, port operations, calling andvarious safety purposes. Safety functions include distress, search and rescue, ship movement, navigation (bridge-to-bridge) communications, and maritime safety information broadcasts. One type of service that can enhance these functions is called a Vessel Traffic Service (VTS). The VTS will enable ships and shore stations to automatically transmit and receive information between themselves in coastal and port areas and inland waterways. Ships will also be able to automatically exchange information on the high seas. The ships and shore stations will be able to exchange data on ship size, speed, location, heading, cargo and other pertinent information, such as navigation hazards and pollution spills.

The Coast Guard plans to operate an Automatic Independent Surveillance (AIS) digital selective calling (DSC) based transponder system as part of the Ports and Waterways Safety System (PAWWS) in the lower Mississippi River. The service area for this Vessel Traffic Service (VTS) system ranges from a 20 mile radius around the sea buoy located at the mouth of the Southwest Pass entrance of the Mississippi River, to river mile 255 above Baton Rogue.

. . .

Therefore, to ensure that the VTS AIS system operates with a minimal amount of RF interference on its VHF data links, the Coast Guard requested that NTIA survey the duplex public correspondence channels and the interstitial channels between them for interference and evaluate their potential to be used as AIS data channels. In addition, the interstitial channels on the edgeof the public correspondence channels were monitored for interference. Personnel from NTIA and the Institute of Telecommunication Sciences (ITS) performed shipboard tests August 10–14, 1998 and shore based tests September 5–9, 1998 to complete these tasks.

Keywords: marine channel survey; automatic independent surveillance; marine radio interference

For technical information concerning this report, contact:

Robert L. Sole

To request a reprint of this report, contact:

Ed Drocella, Chief,
Spectrum Engineering and Analysis Division
Office of Spectrum Management
National Telecommunications and Information Administration
(202) 482-1652

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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