Richtfunkstelle Berlin-Frohnau: Geschichte und Funktion

The Richtfunkstelle Berlin-Frohnau has a rich history dating back to the 1920s. It was built as a transmitter station for radio signals.

Located in the Berlin district of Frohnau, the facility has been an integral part of the city's communication infrastructure for nearly a century. The site's strategic location allowed for efficient transmission of signals across the region.

The Richtfunkstelle Berlin-Frohnau was designed to transmit radio signals at a specific frequency, which was crucial for communication during its time. The facility's architecture and design reflect its original purpose.

Today, the Richtfunkstelle Berlin-Frohnau remains an important part of Berlin's communication network, although its function has evolved over the years.

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The Richtfunkstelle Berlin-Frohnau was a facility for directional radio services in Frohnau, a locality in the Reinickendorf borough of Berlin.

It served as a microwave transmission link between West Berlin and West Germany before German reunification.

A 117.5 m high free-standing steelframe work tower was built for an overhorizon directional link between 1970 and 1973.

This tower was equipped with parabolic dishes of 18 m diameter for an overhorizon link to Gartow in Lower Saxony.

A 358.6 m high guyed mast for conventional directional service was built from 1977 onward.

It carries on a platform aerials for directional services toward Gartow and Clenze, both in Lower Saxony.

The highest floor of all structures in the European Union at the time of the tower's demolition was a room at a height of 300 metres, measuring 4 by 5 metres.

The radio mast was demolished on February 8, 2009 shortly after 1pm local time.

The coordinates of the site are 52°39′11″N13°17′44″E.

The facility was used for test transmissions for DRM on the medium wave frequency 1485 kHz since 2002.

A long wire aerial on a 10 m high mast was built for this purpose, as neither of the towers was designed for use as aerial for AM transmission.

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In the 1960s, two different methods were used to transmit phone calls between West Germany and West Berlin without using infrastructure in East Germany.

The first method used a technique where the send and receive antennas were not in line of sight with each other, and the signals were reflected off the Earth's atmosphere to be received by the other antenna.

This method had its advantages, such as being able to cover long distances with relatively short antennas, but it was also prone to interference from strong storms.

A notable example of this technology was the existing connection between Wannsee and Torfhaus, which spanned around 200 km and provided 3000 phone channels.

Another method, called "Einseitenband-Amplitudenmodulation", allowed for a narrower frequency band to be used, but it was vulnerable to interference from frequency shifts.

This technology was used on the connection between the Schäferberg and Gartow 1, which was around 135 km away.

However, the need for more phone channels led to the idea of creating a connection with line of sight between the antennas, which would allow for more reliable and higher-capacity communication.

This idea involved building a 350-meter-high send mast in West Berlin and a corresponding receiving station in West Germany.

Initially, the plan was to build this connection in the Frohnauer Forst, but it was put on hold due to the success of upgrading the existing connection at the Schäferberg.

The engineers were able to increase the capacity of the Schäferberg connection using additional antennas and modified technology, and they also conducted experiments on a test track for a connection with "streifender Sicht" (a type of line of sight).

These experiments provided valuable insights for the planned project, and the original plan was put on hold.

However, in 1971, a smaller send tower was built in Frohnau, and a corresponding receiving station was built in Clenze, which was a similar technology to the existing connection at the Schäferberg.

This new connection was operational in 1975, but it only provided around 700 phone channels, which was a significant reduction from the planned 3000 channels.

The reason for this reduction was a poor transmission quality, which was later improved by reducing the frequency band.

Despite these efforts, the new connection still had the same drawbacks as the original method, and the original plan was revived in 1977, with the decision to build the Richtfunkmast in Berlin-Frohnau.

The infrastructure of the Richtfunkstelle Berlin-Frohnau is a crucial aspect of its operation. It's built on a 15-hectare site.

The site is located in a relatively remote area, which helps minimize interference from other radio signals. This ensures the high-gain antennas can transmit and receive signals clearly.

The Sendemast 358,6 m was a remarkable feat of engineering, standing at an impressive 358.6 meters tall. It was built between 1977 and 1979 for a staggering 11.5 million DM.

The mast was designed to facilitate a high-frequency radio connection with West Germany, with the receiving station located near Gartow, a town in the state of Lower Saxony. The distance between Berlin-Frohnau and Gartow is approximately 133 kilometers.

The mast had a significant impact on telecommunications, allowing for up to 11,700 simultaneous phone calls to be transmitted through its 10 radio frequency pairs operating between 5 and 8 gigahertz. Its sheer scale is impressive, with a total weight of 920 tons and 3.8 kilometers of cable used for the mast's support system.

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The Sendemast had a unique feature: an elevator that could transport people up to a height of 325 meters. The mast's base measured 4.3 x 4.3 meters, and its foundations required a massive 2,000 cubic meters of concrete.

Here's a brief timeline of the Sendemast's life:

The Sendemast's operational costs eventually became too high, and it was eventually demolished on February 8, 2009.

The Sendeturm in Berlin-Frohnau stands at an impressive 117.5 meters tall.

It was constructed between 1971 and 1972, costing 2.5 million DM.

The tower is made of steel and has a self-weight of 400 tons.

Its foundation is supported by four pillars, each with a 100 cubic meter concrete base.

The original purpose of the tall sendemasten was to transmit messages between Berlin (West) and West Germany over East Germany, but unfortunately, the high mast's abhörsicherheit was just an illusion.

The mast's height was necessary to overcome the Earth's curvature, and prior to its construction, connecting West Berlin and West Germany was only possible with the more prone to interference Überhorizont-Richtfunks technology.

The Richtfunkstrecken were eventually shut down after German reunification, and the parabolantennen were dismantled.

The large mast was briefly used for the Bundeswehr's Richtfunk in the early 1990s, but it never broadcast any TV or radio programs.

Since 2002, the site has been used for experimental DRM transmissions on the 1485 kHz frequency, requiring a separate 10-meter tall Langdrahtantenne to be installed.

Today, the facility primarily serves the Mobilfunk industry.