The Telefunken Kompass Sender was one of the earliest

radio navigation Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination. The basic principles a ...

systems to be deployed. It was developed in 1908 by the

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

electronics firm

Telefunken Telefunken was a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the ''Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ('General electricity company'). The name "Telefunken" app ...

. It was used primarily for long-distance navigation by

Zeppelin A Zeppelin is a type of rigid airship named after the German inventor Count Ferdinand von Zeppelin () who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874Eckener 1938, pp ...

s, and was taken out of service around 1918. The system consisted of a series of 32 individual 60 m long cables supported in the center by a single mast and reaching the ground at their ends, forming a sort of

umbrella An umbrella or parasol is a folding canopy supported by wooden or metal ribs that is usually mounted on a wooden, metal, or plastic pole. It is designed to protect a person against rain or sunlight. The term ''umbrella'' is traditionally used ...

-shaped device. Pairs of cables were wired to each other to form a series of sixteen 120 m long

dipole antenna In radio and telecommunications a dipole antenna or doublet is the simplest and most widely used class of antenna. The dipole is any one of a class of antennas producing a radiation pattern approximating that of an elementary electric dipole w ...

s, now known as inverted-V antennas. The transmitter was first connected to all sixteen antennas and sent the

morse code Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of ...

identifier for the station. After the identifier was sent and a specific time interval had passed, the system started switching on individual dipoles in order around the station. An aircraft located at some distance from the station would first listen for the identifier, and then when the time delay expired, start a stopwatch. Since the pattern broadcast from the dipoles was highly directional, they would hear the signal grow in strength as the powered antennas "approached" them, the strongest signal being when the powered set was at right angles. It was later discovered that the minimum point was much easier to distinguish, with the signal dropping almost to zero when they were aligned directly off the end of the powered dipole. Like many radio navigation schemes, the Kompass Sender produced identical patterns along the selected path, as well as the 180 degree reciprocal course. This ambiguity had to be eliminated by taking a second measurement using some other navigation system. For this purpose, two Kompass Sender stations were built, at

Kleve Kleve (; traditional en, Cleves ; nl, Kleef; french: Clèves; es, Cléveris; la, Clivia; Low Rhenish: ''Kleff'') is a town in the Lower Rhine region of northwestern Germany near the Dutch border and the River Rhine. From the 11th century ...

near the Dutch border, and at the German Zeppelin base at

Tønder Tønder (; german: Tondern ) is a town in the Region of Southern Denmark. With a population of 7,505 (as of 1 January 2022), it is the main town and the administrative seat of the Tønder Municipality. History The first mention of Tønder might ...

in today's Denmark. Together the stations offered service over the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

and

English Channel The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" (Cotentinais) or ( Jèrriais), (Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kana ...

areas.

References

* Annis Salsbury, "Safeguarding Vessels by Radio", ''Popular Science'', January-June 1916, pp. 451-453 * Arthur Bauer
"Some historical and technical aspects of radio navigation, in Germany, over the period 1907 to 1945"
26 December 2004 * "How the Zeppelin Raiders Are Guided by Radio Signals", ''Popular Science'', April 1918, pp. 62-634 {{refend Radio navigation

See also

References