National Distress System
Encyclopedia
The U.S.
National Distress System (NDRS) was established more than 30 years ago as a VHF-FM
-based radio
communication system that has a range of up to 20 nautical miles (40 km) along most of the U.S. shoreline for the United States Coast Guard
. While this system has served the Coast Guard
well over the years, it consists of out-of-date and non-standard equipment with many limitations. This system is being replaced by Rescue 21
.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
National Distress System (NDRS) was established more than 30 years ago as a VHF-FM
FM broadcasting
FM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation to provide high-fidelity sound over broadcast radio. The term "FM band" describes the "frequency band in which FM is used for broadcasting"...
-based radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
communication system that has a range of up to 20 nautical miles (40 km) along most of the U.S. shoreline for the United States Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
. While this system has served the Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
well over the years, it consists of out-of-date and non-standard equipment with many limitations. This system is being replaced by Rescue 21
Rescue 21
Rescue 21 is an advanced maritime computing, command, control, and communications system designed to manage communications for the United States Coast Guard.-Overview:...
.
Limitations
Limitations include:- No direction finding capability.
- Numerous geographic communication's coverage gaps.
- Limited interoperability with other emergency response services.
- Single-channel radio operation, which prohibits the ability to receive multiple radio calls.