Distress signalA distress signal, also known as a distress call, is an internationally recognized means for obtaining help. Distress signals are communicated by transmitting radio signals, displaying a visually observable item or illumination, or making a sound audible from a distance. A distress signal indicates that a person or group of people, watercraft, aircraft, or other vehicle is threatened by a serious or imminent danger and requires immediate assistance.
Marine VHF radioMarine VHF radio is a worldwide system of two-way radio transceivers on ships and watercraft used for bidirectional voice communication from ship-to-ship, ship-to-shore (for example with harbormasters), and in certain circumstances ship-to-aircraft. It uses FM channels in the very high frequency (VHF) radio band in the frequency range between 156 and 174 MHz, designated by the International Telecommunication Union as the VHF maritime mobile band.Pan-panThe radiotelephony message PAN-PAN is the international standard distress signal that someone aboard a boat, ship, aircraft, or other vehicle uses to declare that they need help and that the situation is urgent, but for the time being, does not pose an immediate danger to anyone's life or to the vessel itself. This is referred to as a state of "urgency".
Maritime Mobile Service IdentityA Maritime Mobile Service Identity (MMSI) is an assigned Unique identifier (UID), comparable to a maritime object's international maritime telephone number, issued by that object's current flag state (unlike an IMO number, which is a permanent global UID). When the vessel changes ownership or name within the same country of registration then the assigned MMSI remains with the vessel. If the ship is reflagged then the different country’s (flag state) MMSI must be assigned.
Global Maritime Distress and Safety SystemWorldwide emergency communication system for ships at sea The Global Maritime Distress and Safety System (GMDSS) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations' International Maritime Organization (IMO) as part of the SOLAS Convention. It is a set of safety procedures, types of equipment, and communication protocols used for safety and rescue operations of the distressed ships, boats, and aircraft.Analog signalAn analog signal (American English) or analogue signal (British and Commonwealth English) is any signal, typically a continuous-time signal, representing some other quantity, i.e., analogous to another quantity. For example, in an analog audiosignal, the instantaneous signal voltage varies in a manner analogous to the pressure of the sound waves.
Global Positioning SystemAmerican satellite-based radio navigation serviceArtist's impression of GPS Block IIIA satellite in Earth orbitLate 1990s civilian GPS receiver ("GPS navigation device") in a marine applicationAutomotive navigation system in a taxicab, 2000sA United States Space Force officer operates the Global Positioning System in 2022.International Terrestrial Reference SystemSpatial Reference System Identifier (SRID)Universal Transverse Mercator (UTM)SquelchIn telecommunications, squelch is a circuit function that acts to suppress the audio (or video) output of a receiver in the absence of a strong input signal. Essentially, squelch is a specialized type of noise gate designed to suppress weak signals. Squelch is used in two-way radios and VHF/UHF radio scanners to eliminate the sound of noise when the radio is not receiving a desired transmission.
Medium frequencyEU / NATO / US ECM ABCDEFGHIJKLMNIEEE HFVHFUHFLSCXKuKKaVWmm Other TV and radioIIIIIIIVVVIMedium frequency (MF) is the ITU designation for radio frequencies (RF) in the range of 300 kilohertz (kHz) to 3 megahertz (MHz). Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hectometer band as the wavelengths range from ten to one hectometers (1000 to 100 m).
Radio receiverIn radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. The antenna responds to radio waves (electromagnetic waves of radio frequency) and converts them to tiny alternating currents which are applied to the receiver, and the receiver extracts the desired information.
High frequencyEU / NATO / US ECM ABCDEFGHIJKLMNIEEE HFVHFUHFLSCXKuKKaVWmm Other TV and radioIIIIIIIVVVIHigh frequency (HF) is the ITU designation for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters).
Signal transmissionIn telecommunications, transmission (sometimes abbreviated as "TX") is the process of sending or propagating an analog or digital signal via a medium that is wired, wireless, or fiber-optic. EtymologyThe origin of the words transmit and transmission and their derivatives go back to the Latin word transmittere, in turn formed by prefixing the preposition trans (“across or beyond”) and the verb mittere (“to let go or to send”).*As an Amazon Associate I earn from qualifying purchases.