Marine VHF radio

The mobile maritime mobile service on ultra-short wave is a part of the maritime mobile service, which is provided exclusively for radio communications over ultra-short wave.

History

By 1972 there were in the maritime mobile service on Ultrakurzwelle 28 channels, which was assigned a fixed frequency. In 1972 it was possible to halve by improved radio equipment technology, the frequency spacing of the channels. Thereby created between the frequencies of the existing channels, the additional channels 60 - 88

Prerequisite for participation in the maritime mobile service on FM

In principle, any watercraft has the opportunity to participate in the maritime mobile service on FM on tidal waters.

Prerequisite for participation was up 31 May 2013 that is approved for the marine radio transceiver and a frequency assignment certificate. Since June 1, 2013, the frequencies for mobile radio applications of maritime and inland navigation radio are generally allocated. The actual use permit is dependent on the prior individual allocation of numbers by sea and inland waterways such as call sign, Maritime Mobile Service Identity ( MMSI ) and / or Automatic Transmitter Identification System Number ( ATIS ). The previously issued certificates remain valid until the application for a change in the assignment of numbers. An exchange of existing certificates by new number allocation documents is therefore not provided.

Furthermore, it must be in possession of sufficient valid radio operating certificate to the skipper. For radio communications at sea on the VHF SRC is prescribed as a radio license for commercial shipping and the ROC for the recreational marine environment.

Equipment requiring ships to participate in the maritime mobile service on FM.

The radio channels and their frequencies

For the maritime mobile service, the frequency range 156-162 MHz is provided on FM. In this frequency range, there is a fixed frequency, can be sparked on those. The individual channels have a fixed rate and a fixed term. Some channels are required for a particular use.

Simplex and Duplex

In the maritime mobile service on Ultrakurzwelle a distinction between simplex and duplex voice process.

Simplex

The simplex voice process takes place on a single frequency. This means that only one radio station can talk while the other listens. Send both stations at the same time, both stations hear anything. Ship stations and coast stations using the same frequency. Conversations on simplex channels can in principle be heard by all ship stations, hence the emergency channel 16 is a simplex channel.

Duplex

In duplex intercom method, the respective stations (eg ship station and coast station ) use two different frequencies, both of which belong to a channel. This method allows the coastal radio station as a communication with a telephone, a frequency is responsible for receiving, the other frequency for transmission. When duplexing, the radios of the ship stations ( semi-duplex ) automatically switch to the receiving frequency of the coast station (RX ). Only when the Talk button is pressed, the radio switches to its own transmission frequency ( TX). This method makes switching between transmit and receive for coast stations unnecessary. In addition, prevents the duplex method that ship stations listen to transmissions from other ship stations. Only the transmissions of coast stations can generally be overheard in the duplex method of all. Often, however, the coast station on its receiving frequency Receive transmits on its transmission frequency.

Range

The range of ultra-short waves is limited by the horizon of the electromagnetic wave propagation. This does not correspond to the optical horizon for the visible light because the refractive index of the atmosphere decreases for the FM band with the height above ground. In practice this means that the relevant range is dependent on the height of the antenna. Ships on which the antenna is mounted at the highest possible point ( commercial shipping, sailing yacht), can spark each other up to a distance of approximately 30 nautical miles ( about 56 km). The range on Digital Selective Calling is about twice as far.

Costs

Basically, the use of the maritime mobile service on FM for free, both sending and receiving.

However, there are also private coast stations that offer paid services. Most popular private providers of radio services in Germany is DP07.

Also, the issuing authority for frequency assignment certificate can ( the Federal Network Agency in Germany ) require annual fees for issued frequency assignment certificate. The fees are usually less than 20 € a year.

Scope

Due to the low range of the VHF marine radio, mobile maritime mobile service on Ultrakurzwelle in commercial vessels is mainly used for the onboard radio communications and radio communications with area radio centers, traffic control, ship steering radio service, pilots, ports and locks as well as the radio communication with other vessels in heavily traveled traffic areas.

In the recreational marine environment of the mobile maritime mobile service on ultra-short wave is mainly for social communication, the contact area radio centers, ports and locks, as a source of information for weather and navigational warnings and the possibility of sending an emergency call.