500 kHz

The frequency 500 kHz or 600 m is the international distress frequency since the introduction of the maritime radio. The specific mention of the frequency 500 kHz and 600 m wavelength from the frequency spectrum is based on the extraordinary long, exclusive and specially protected use in the maritime mobile service. The frequency was almost 80 years ago, the International calling and distress frequency in the maritime radio service.

Overview

The use of the frequency 500 kHz was governed by administrative radio conferences. Here are the rules were laid down that the Parties had obliged themselves to observe and follow. In the Radio Regulations Radio Regulations ( Radio Regulations, Eng. Radio Regulations ) all details were laid down for the engineering, traffic management, education and training of the personnel of the sea and coast stations, the billing process and much more.

With the launch of the first satellite Sputnik on 4 October 1957, a new era in the maritime mobile service announced. However, it took several decades, until it came to the introduction of an automated radio service via the Inmarsat communications satellite system in the late 1980s. The interests of ship safety and distress Funke were included in the GMDSS system. The further use of specially trained personnel for the operation of the ship stations in Morse was unnecessary.

Basis of the signaling of all stations with each other was by then the Morse telegraphy after Gerke code. The main means of communication in the maritime industry was the telegram. Ships of a certain size had to be equipped with medium-wave radio equipment. With these plants, only one Morse was possible. The use of short - and boundary waves in marine radio was not until many years later.

Former radio officers have been trying for several years (1995 ) to regain the memory of the telegraph and the 500 kHz by inclusion in the list of UNESCO World Heritage Sites of non-material goods.

In the fall of 1886, the existence of invisible electromagnetic waves by Hertz at the University of Karlsruhe has been demonstrated. First, you could with the new airwaves, as they were called, do anything meaningful. In the absence of technical options available it was not possible to bridge larger distances than a few kilometers. Only through intensive experiments of Marconi (Villa Griffone, 1895 ), Slaby (Berlin, AEG, 1897), Preece (England, 1897), Brown (Strasbourg, Siemens 1899) and others succeeded until 1900, distances of up to bridge to 100 kilometers. These distances could "see" beyond the horizon. The great utility of this system for the shipping industry became apparent quite clear and has been driven mainly in England, Germany, USA and Italy.

Long wave

Initially, it was only able to produce long waves of sufficient energy and they prove in mechanical receivers ( coherer after Branly, Eng. Fritter ). For the emission of longwave extensive antenna systems are required, which can be accommodated only with difficulty on a ship. The first transmitter generated via radio links ( pop radio transmitter ) strongly damped waves.

Transmitter

With the invention of the quenched spark transmitter by Max Wien (1905 ) were able to produce nearly undamped waves. The frequency can be adjusted more accurately and by operating at 500 Hz alternating current produces a singing tone of 1000 Hz These stations are also called ' sounding sparks ' and found in marine radio rapid application after this circuit. Marconi developed a rotary spark gap, in which a motor-driven wheel with many contacts formed the spark gap. With this device was similar to the quenched spark transmitter for a rapid termination of the spark of the spark gap taken care of and so causes a rapid and common result of rollovers.

Radiocommunication Conferences

After the radio equipment could always bridge larger distances, an intergovernmental regulation of the air operation was considered necessary. Thus invited the German Reich government in 1903 for a first radio conference. On the second radio conference in Berlin in 1906, the shaft was proposed 600 m as an international standard for the maritime mobile service. Some countries did not take part in the conference or consent was not fully in the agreement and pursued national, private-sector goals.

As a replacement for the existing distress signal CQD (also known as "come quick danger" named) was the later binding distress signal SOS (also known as " save our souls" ) is proposed. This proposal is not justified it because it sounds so beautiful in plain text, but because the reaction in Morse code is more concise than using the CQ (general call to all Station). The CQ was constantly used by the radio stations and a CQD was able to be more easily ignored.

500 kHz standard

Following the investigation after the sinking of the RMS Titanic (call sign MGY ) on April 14, 1912 were introduced on the third radio conference in July 1912 in London major regulations. It was agreed that all radio stations with each contact, regardless of the system used. Previously, it was, for example, is controlled so that stations with Marconi equipment only with each other wrong, usually indicated by an exclamation mark, which began with the letter M. It was further stipulated that in future a constant listening watch should be maintained at 500 kHz.

Radio personnel

The manufacturers of radio equipment equipped the ships with the devices and presented simultaneously trained personnel available. The radio officers were employees of these companies and were rented along with the equipment to the shipping companies. The equipment of passenger ships standing in the foreground, as was expected by many people on board with a high volume of telegrams and thus gave good earning opportunities for the companies. The equipment of the other merchant ships, however, was hesitant because it was not required to have a radio installation on board. In England and Italy and also on ships of other nations assets of Marconi companies were incorporated. In Germany, founded in 1907, ' German operating company for wireless telegraphy ' DEBEG took these tasks was. It had been founded at the behest of Emperor Wilhelm II and brought together the activities of rival companies AEG, Siemens, Telefunken and Lorenz.

The radio officers took part in the public exchange of messages and were on the secrecy obligation, since they received through their activities knowledge of the news content. With the threat of jail time they were allowed to pass on to any third party the information they have acquired. A radio officer on a merchant ship had recently eight hours service were completed in a two -hour watch, two hours off watch system, up to eight hours. In the free guards and in the time of absence from the radio room, the car alarm device ran. This was a receiver which was tuned to 500 kHz and could evaluate the car alarm signal consisting of a sequence of 12 Sendertastungen of four seconds in duration. After the fourth signal it had to trigger an alarm in the living room of the radio officer and on the bridge. The design of the radio officers after 1950 in Germany was made ​​to maritime colleges. After passing an examination in the telecommunications authorities, they received a patent be issued, with which they could strive for a job in shipping companies.

As in other professions, the radio officer was greeted with all sorts of nicknames, which are: Sparks, Marco Ista, Funkenpuster, radio operators, Telgraphista. The reference to radio goes back to the early days of the art, when the first stations were actually large spark generator.

In many cases, took over the radio officer and the administrative work, resulted in foreign ports by the Einklarierung etc.

Operation

Starting point of the operation of ship station was sharing a frequency of 500 kHz. Coastal radio stations were obliged to be constantly send and receive data. Each participant in the radio traffic called to other stations when the frequency was not busy. If you wanted to get in touch with a station, she was called to 500 kHz, and agreed to an alternative frequency to handle the traffic behind. Coastal radio stations announced special mailings such as weather reports, navigational warnings and Ice collection lists to 500 kHz, in order to then send on a different operating frequency. All shipments were interrupted in each case to the distress pauses for three minutes to allow the ship stations interception of 500 kHz. Depending on the transmission power ranges were achieved by 500 nautical miles. Coastal radio stations with higher transmission power were heard and at distances of more than 1500 nautical miles.

To overcome the language barrier, there was a system of standardized abbreviations. These Q- groups an understanding with respect to the radio traffic and the operation processing was possible. Over the years, further, not laid down in the Regulations established abbreviation (eg gm for " Good Morning " ), which were generally used.

Silent period

On subsequent radio conferences, the silent period (SP, silence period ) has been introduced. Every half hour 15 to 18 as well as the 45th and 48th minute of each other radio traffic is to set up and listen to the 500 kHz on the receiver if a distress situation exists. A rescue operation is generally introduced by the car alarm sign, followed by the alarm message. Only the captain retains the right to explain the distress situation and to demand appropriate alarms.

Marine radio in Germany

In 1897, the lecturer went to the Technical University of Berlin Charlottenburg, Slaby, England and was an eyewitness to the radio experiments of Marconi on May 15, 1897 between Lavernock Point and the island of Flat Holm in the Bristol Channel. Slaby worked in Berlin next to the improvement in technology and became the company AEG close. None of the pioneers it was until 1900 managed to overcome 100 kilometers or more.

In early 1899, continued Prof. F. Braun and his close associates Cantor and Zenneck which started in Strasbourg radio experiment on the North Sea in Cuxhaven on. The experiments lasted until the fall of 1900. The cruise liner Sylvana the North Sea lines, ran between Cuxhaven and Helgoland, served as the test vehicle. The land station was initially located at the lighthouse on the Old Love. Later, the plant was moved to Kugelbake in Dosen. Here succeeded on 24 September 1900, the safety override of 62 kilometers to the island of Helgoland. The fire ships in the Elbe estuary were equipped with radio equipment and participated in a ship reporting service. In October 1900, the Emergencies of the stranded ship Bremen full Bischoff was signaled to Cuxhaven and fetched help.

In May 1900, the first commercial -powered radio link between Borkum and the lightship Borkum Riff was put into operation. The equipment was supplied by Marconi, built by the Waterways and Shipping Administration and operated and paid for by the shipping company North German Lloyd. Your fast steamer Kaiser Wilhelm der Grosse was also equipped with a Marconi - conditioning and pre-populated with a Marconi wireless operator.

In 1907, the coast station Utlandshörn was taken after several years of preparation by the imperial postal service for public transport with ships in the North Sea in operation. This coastal radio station with the call sign DAN was last over the years to one of the major stations of the world. In the maritime mobile service, the large radio stations Nauen, Königswusterhausen and Eilvese at Hanover were at times involved. In the eastern part of Germany until 1989 divided the coastal radio station Radio Rügen took the radio service true.

At the end of the 1990s, Morse was completely discontinued after the Morse code Gerke on medium and short waves for navigation in the maritime radio operated countries. The once- famous call sign of coast stations and their airwaves in telegraphy have been silenced forever. Next persisted a working method for automatic radio network on short wave, can be exchanged via the telex and e-mail.

The marine radio itself but lives on and the technological revolution has freed the sailors from their centuries of isolation.

500 kHz today

The frequency 500 kHz is still used as a call - and Notfunkfrequenz. The distinctive clock associated with the selected Hörwachezeiten still on the bridges of many ships. Antenna systems for the frequency 500 kHz are costly to implement ( lambda = 300 m half ). Today there are other systems in use and prescribed for alerting in distress cases. GMDSS equipment are now mandatory on all larger ships. Depending on the sea area is a DSC watch receiver and transmitter for the FM channel 70 prescribed ( sea area A1 and A2). For the great journey the ships must have a cutoff wavelength system with the distress frequency 2182 kHz today. The ships have an automatic alarm signalman ready keep 2182 kHz for this frequency.

However MRCCs as the Bremen radio Rescue the GMRS keep still listening watch on 500 kHz.