Shortwave broadcasting

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World receiver , set to 3980 kHz shortwave (KW, English SW )

The term short-wave broadcasting refers to a form of radio broadcasting , the terrestrial via shortwave is widespread.

International broadcasting

Shortwave signals have a very long range due to their very good reflection properties in the ionosphere . This is why radio stations that are broadcast on shortwave have the property of being receivable all over the world if the frequency is chosen skilfully .

Because of the large range of shortwave signals, the lion's share of shortwave broadcasting consists of national broadcasters, which serve to present their respective country abroad in the media and to provide information to citizens of their own country living abroad ( international broadcasting ).

In Germany, this task was carried out by Deutsche Welle , which, however, largely stopped its shortwave broadcast operations on October 29, 2011 . In Austria, in the spring of 2003, the international service Radio Austria International was discontinued by the Austrian Broadcasting Corporation , amid great protests from listeners. Since then, the national program Ö1 has been broadcast on shortwave for almost an hour a day, and since 2011 at the latest 70–80 minutes a day . Switzerland also discontinued its international service, Schweizer Radio International, at the end of October 2004 . Instead, the offer was shifted to an Internet presence; news and reports are offered there.

The reasons for discontinuation are often high costs and poor sound quality.

Shortwave transmitters often have a transmission power of 100 kW ( ERP ) up to 500 kW. An alternative, however, is the digital modulation of short-wave signals, which is funded by the Digital-Radio-Mondiale consortium (DRM consortium).

The target groups and program mandate of international broadcasting are described below:

  • Tourists and citizens of their own country living abroad should be provided with information from their home country.
  • Foreign listeners receive information and background reports on the respective country in their own language. A large part of this group of listeners also engages in international radio reception as a hobby known as DXing .
  • So-called opinion leaders, such as journalists , listen to foreign broadcasters to get information from the country that interests them from the first source. Some states maintain press services that listen to international broadcasters and make the information available to the government in summary reports.

In some countries, shortwave broadcasting is also of great importance for national broadcasting coverage, for example in some Asian countries and in India or Australia. There are the following reasons for this:

Satellite radio and the Internet have greatly reduced the importance of shortwave broadcasting in Europe, North America and Australia. Some international broadcasters have even partially stopped their shortwave programs for these target areas, such as the BBC World Service for North America and Western and Central Europe.

However, new media analyzes show that many shortwave listeners have not switched to the Internet.

Radio reception enables anonymity that is not possible on the Internet. In addition, it is often significantly easier to take a small shortwave receiver with you than to get access to the Internet or a satellite reception system.

Broadcast bands in the shortwave range

Overview of the radio bands
Meter tape Frequency range comment
120 m 2,300-2495 0kHz Tropical band , boundary wave
90 m 3,200-3,400 0kHz Tropical band, boundary wave
75 m 3,900-4,000 0kHz not in America
60 m 4.750- 05.060 kHz Tropical band
49 m 5,900-6,200 0kHz worldwide
41 m 7,200-7,450 0kHz worldwide
31 m 9,400-9,900 0kHz worldwide
25 m 11,600-12,100 kHz worldwide
22 m 13,570-13870 kHz worldwide
19 m 15,100-15,800 kHz worldwide
16 m 17,480-17,900 kHz worldwide
15 m 18,900-19,020 kHz worldwide
13 m 21,450-21,850 kHz worldwide
11 m 25,670-26,100 kHz worldwide

In contrast to domestic VHF transmitters, which broadcast around the clock on a fixed frequency , shortwave transmitters have to change their frequencies several times a day. The reason is the dependence of the propagation conditions of the shortwave signals on the time of day and time of year.

The frequency ranges assigned to the radio service on shortwave - also called frequency bands or meter bands - are distributed over the entire shortwave spectrum . A 5 kHz grid is used within the bands (carrier frequency xxxx0 kHz and xxxx5 kHz). However, some transmitters also work outside of these bands and, because of their much higher field strengths, make the corresponding frequencies unusable for practically all legitimate users. The adjacent table gives an overview of all radio bands in the shortwave range.

For historical reasons (in the early days of radio you could only measure wavelengths, but not count frequencies), the radio bands are named after their approximate wavelengths . For example, the frequency of 6100 kHz corresponds approximately to a wavelength of 49 meters. Therefore, the frequency range from 5900 kHz to 6200 kHz is called the 49 meter band. In the evenings, almost all European international channels can be received on the 49-meter band. So the 49-meter band is often also Europe band called.

Former German-speaking shortwave radio stations in the 49 and 41 meter bands

Propaganda, free source of information and underground broadcaster

Because of its great range, shortwave broadcasting also played an important role in World War II . It served primarily as a propaganda tool . On the German side, the German short-wave transmitter, which was subordinate to the Reich Propaganda Ministry, broadcast Nazi propaganda in many languages ​​all over the world; Germany Calling was one of the larger German international broadcasters . In addition to their state broadcasters, the Allies and the Germans put together programs with “black propaganda”, that is, targeted disinformation, the British, for example, in the form of the camouflaging soldier channel Calais .

In Germany , listening to the war opponent's shortwaves was punished as a radio crime. H. the reception of " enemy channels ", above all the BBC, which for many Germans was the only source of unadorned information about the course of the war. However, only a minority of the population had the necessary reception devices. The popular receiver models (the VE301 and its successors), affordable for the general public, were purposely designed only for the long and medium wave ranges and, due to their simple construction, only suitable for local and district reception. This is why the legend still holds up to this day that the reception of foreign stations was prevented by targeted technical manipulation of these devices - popularly known as Goebbelsschnauze or Schreiender Jupp .

Even before the war, privately operated shortwave transmitters flourished because they enabled small political groups to be heard around the world. The Hitler government took drastic measures against it and tightened the "law against black transmitters" on November 24, 1937: "From now on black broadcasts will be punished with prison," writes engineer Fritz W. Behn at the beginning of his non-fiction book about the construction of shortwave transmitters. The amendment to the law punished anyone who built such a transmitter without the approval of the Reichspost or kept it in prison. In order to give his electrotechnical book the appropriate, deterrent tone, Behn made himself the mouthpiece of the legislature:

“It is irrelevant whether individual parts or connections of the transmitter are still missing or have been removed. So excuses that the transmitter is not finished and not operational are useless. Also [...] wave meters that emit electrical vibrations fall under the term 'radio transmission systems'. The Deutsche Reichspost only grants broadcasting permits to radio enthusiasts who are members of the […] German Amateur Broadcasting and Receiving Service e. V., Berlin-Dahlem, Cecilienallee 4 [are]. "

The role of shortwave broadcasting changed during the Cold War , when the opposing side could receive propaganda broadcasts in their national language over the shortwave. Such broadcasters were, for example, the broadcasters Radio Free Europe / Radio Liberty , financed from US sources , which broadcast anti-communist programs in Eastern European languages. In the opposite direction it was, for example, Radio Moscow , Radio Tirana or Radio Peace and Progress . Radio Sweden International , for example, tried to position itself as neutral .

Listening to Eastern Bloc stations in the USA during the McCarthy era could be viewed as anti-American activity and could have serious consequences for the listener. In the communist or Stalinist countries, listening to foreign broadcasts was illegal at certain times. The broadcasts were disturbed by jamming transmitters , which emitted background noises such as whistling, hissing or babble of voices on the shortwave frequencies used (so-called jamming ). This is seen as a violation of the human right to free choice of information source. Broadcasters such as Deutsche Welle, radio in the American sector ( RIAS Berlin), Voice of America and the BBC World Service were also disrupted.

Another possibility to interfere with the reception of foreign radio stations is to operate national stations on the frequencies of unpleasant stations. Some Cuban radio stations broadcast their domestic programs on the frequencies of Radio Martí and other popular medium wave stations from Florida to make reception in Cuba more difficult. In Iraq, Radio Baghdad's domestic service used some of the shortwave frequencies from Radio Sawa , the Voice of America's Arabic program.

Even today, there are still opposition and underground stations ( clandestine stations ) on shortwave , which, depending on the location, are operated illegally (according to the local legal interpretation at the station location), tolerated or legally. Such channels are often, but not always, noticed by technical problems. Typically, the transmission technology used is old or very limited, including the use of amateur radio technology and self-construction. Transmitters are operated, often by necessity, in unfavorable locations with unfavorable and inadequate antennas, and the operators' technical experience is poor. In addition, the selected broadcast frequencies are not internationally coordinated. Broadcasting outside of the bands reserved for broadcasting, albeit often only just outside, is also common. From a technically perfect operation it can often be concluded that the station is materially and financially well equipped and is at least tolerated at its location.

Iraq, Afghanistan and North Korea are (as of 2006) popular target areas for opposition and underground broadcasters. Africa is currently (also in 2006) experiencing a renaissance of such channels.

Shortwave Broadcasting Today

Due to its special propagation conditions, shortwave offers the possibility of receiving radio broadcasts from every country in the world. These programs offer the advantage of receiving news directly from the first source - not quoted or lectured, as is the case in the domestic media. This is a particular advantage of shortwave reception.

For example, it is possible to experience the atmosphere of an emotionally charged South American football game live via shortwave or to hear the latest news and music from countries that are rarely mentioned in the local media.

Today radio stations from over 30 countries broadcast programs in German. Most of these are information and entertainment programs lasting between a quarter and two hours and broadcast to Europe in the evening hours.

Shortwave reception as a hobby

In German-speaking countries, many people practice shortwave reception as a hobby - more than 4,000 listeners are even organized in shortwave listeners' clubs. Reception from distant local radio stations is called DXen . Shortwave listeners can send reception reports to the broadcasters and have receipt confirmed with QSL cards . The interesting and varied presentation of the cards makes them popular collector's items. Conversely, these reception reports are also very important for the transmitters, as they provide information about the propagation conditions and range. Long-distance reception on other wave ranges, such as medium and long wave, is confirmed with QSL cards.

The SINPO system is often used in reception reports to assess the reception quality . This is a numerical code that describes the signal strength, interference, background noise and fading .

Alternatively, the SIO code is used, which provides a less detailed description. This type of reception report was used by DXers for reports to large international broadcasters. For smaller local broadcasters, the reception is usually written in the form of a personal report. Alternatively, there is also the RST system .

International broadcasters depend on close contact with their listeners. So this is the only way to get a response to your broadcasts. Listeners and broadcasters often maintain a friendly relationship with one another by post or, more recently, by e-mail and occasionally add small souvenirs such as stickers or pennants to their correspondence .

Private providers

In connection with the end of shortwave broadcasts from public service providers, there are more and more small private shortwave operators in German-speaking countries (e.g. shortwave service since 2007). The pioneers in the private sector were originally religious stations, including the gospel radio (ERF, 1961). In 1993–95 the information program Radioropa Info was broadcast on shortwave from the Czech Republic . Transmitting systems have also been used by private providers in Germany and Austria since the 2000s. In the USA, the National Association of Shortwave Broadcasters (NASB) was founded in 1989.

Current trends

Shortwave transmission is based on reflection effects on different layers of the ionosphere . The structure of the ionosphere is largely determined by sunspot activity, which increases or decreases in an approximately 11-year cycle. In a sunspot minimum, the shortwave works much worse than in times of maximum. Since 2008, the sun has been in an unusually long minimum, which probably ended in 2011. But it is in the nature of such processes that they can only be analyzed afterwards.

Software-defined radio

You don't have to own a shortwave radio to watch international radio. These days, dedicated DXers will use software-defined radio (SDR) because this technology offers the best possible reception. Using so-called waterfall diagrams, you can also observe entire frequency bands live and specifically tune them to frequencies on which a carrier signal is currently being sent. With so-called WebSDR you can access open SDR receivers around the world via the Internet, which can be remotely controlled via the web browser, and in this way, for example, listen to programs in Europe as they can be received in Tokyo if you have a receiver there locates. The WebSDR streams the signal live in the user's web browser. At peak times, such services are often used by several hundred users at the same time.

Internet radio

The operation of shortwave transmission systems is relatively expensive. Since with the end of the Cold War both the motivation to broadcast for propaganda reasons and the need to provide “neutral” information no longer existed, there is a trend to discontinue or reduce shortwave broadcasts ( e.g. Danmarks Radio , Radio Monte Carlo , Voice of the Mediterranean , Radio Austria International , Radio Tirana , IBB / VoA , the German-language broadcasts from Radio Sweden and the BBC World Service for Europe and North America). Often, references are made to internet radio or podcasts as possible substitutes .

Operating an Internet radio or broadcasting a radio broadcast over the Internet is incomparably cheaper than operating shortwave transmitters. There are no frequency shortages or problems with wave propagation. The ranges that can be achieved via the Internet are large - but precisely those areas are not reached that are technically undersupplied or in which divergent views are suppressed by the state for political reasons and in which the Internet is consequently also censored (e.g. China , Iran , North Korea ). In these areas, shortwave broadcasting continues to be one of the few real sources of information.

Digital shortwave radio using DRM

The FM radio due to the used frequency modulation (FM) and a wider range a much better reception quality than that used in the short, medium and long wave amplitude modulation offer (AM). With the worldwide increasing spread of FM transmitters, even in remote areas, FM as a modulation type is gaining significantly greater popularity than broadcasts in the AM area. The number of shortwave transmissions has declined in recent years. In order to optimize the reception quality of the stations, one would like to use digital shortwave (DRM) in the future.

On June 16, 2003, the Digital Radio Mondiale (DRM) went into regular operation at the World Radio Conference (WRC) in Geneva . Little by little, some shortwave transmitters are now broadcasting digitally in addition to conventional AM broadcasting. At the International Radio Exhibition Berlin 2003, digital receivers with DRM decoding were presented for the first time.

To date, there are only a few DRM-compatible shortwave receivers that are also relatively large, have a high power consumption and usually also have comparatively poor reception performance.

Reception impairments

Shortwave reception can be impaired by natural and other influences. The natural influences that are referred to as radio weather are, for example:

  • Activities on the sun (sunspot minimum, sunspot maximum); this changes the ionizing layers that reflect the shortwave bands.
  • Thunderstorm , the characteristic shortwave "cracking" caused by lightning discharges.

The unnatural influences include, for example

In the operating instructions of the PLC devices you will usually find a note similar to the following: This device can cause radio interference in living areas; in this case, the operator can be required to take appropriate measures.

Selection of some shortwave transmitters

This list shows important shortwave stations without claiming to be exhaustive or up-to-date.

International foreign channels :

National channels on shortwave :

U.S. international channels :

Missionary Broadcasters / Religious Programs :

Former international channels :

See also

Portal: Radio  - Overview of Wikipedia content on radio

literature

  • Michael Schmitz, Wolf Siebel: Sender & Frequenzen 2017 - Yearbook for worldwide radio reception , 34th year. vth - Verlag für Technik und Handwerk neue Medien GmbH, Baden-Baden, ISBN 978-3-88180-896-5 .
  • WRTH Editors (Ed.): World Radio TV Handbook (WRTH) 2019 , 2019, ISBN 978-1999830014 .
Frequency plan

Audio broadcasts

Web links

Individual evidence

  1. ↑ Introduction to shortwave. ukwtv.de
  2. ↑ Overview. In: oe1.ORF.at. Österreichischer Rundfunk, March 24, 2011, accessed on September 14, 2019 .
  3. ↑ swcountry.be
  4. ↑ Frith W. Behn: The short wave transmitter . Weidmannsche Verlagbuchhandlung, Berlin 1939
  5. ^ NASB: About us
  6. ↑ An overview of open WebSDR is provided by websdr.org . The WebSDR of the University of Twente in the Netherlands is popular.
  7. ↑ DRM receiver / receiver chips ( memento of the original from July 12, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . In: German DRM Forum. Retrieved July 11, 2015 (overview of the DRM radios currently available in stores) @1@ 2Template: Webachiv / IABot / www.drm-forum.de
  8. ↑ Radio-Kurier - listen worldwide 17/2001 (PDF)