NMSAT :: Networked Music & SoundArt Timeline

1920 __ DXing
French comment : As radio developed in the early 1920s, the focus for most people was the AM band and early domestic broadcasting stations like KDKA. However, as knowledge about the capabilities of various frequency ranges increased, another broadcast method developed and became popular among many early listening enthusiasts. It was shortwave broadcasting. Unlike amateur radio, where hobbyists operate their own stations and talk with one another over the air, shortwave broadcasting is the transmission of news and entertainment over great distances via shortwave for the listening public. Such long-distance ("DX") listening was an exciting aspect of the new medium of broadcasting. (Jerome Berg, “On the Shortwaves, 1923-1945”)DXing is the hobby of tuning in and identifying distant radio or television signals, or making two way radio contact with distant stations in amateur radio, citizens' band radio or other two way radio communications. Many DXers also attempt to receive written verifications of reception (sometimes referred to as "QSLs" or "veries") from the stations heard. The name of the hobby comes from DX, telegraphic shorthand for "distance" or "distant". Early radio listeners, often using home made crystal sets and long wire antennas, found radio stations few and far between. With the broadcast bands uncrowded, signals of the most powerful stations could be heard over hundreds of miles, but weaker signals required more precise tuning or better receiving gear. By the 1950s, and continuing through the mid 1970s, many of the most powerful North American "clear channel" stations such as KDKA, WLW, CKLW, CHUM, WABC, WJR, WLS, WKBW, KFI, KAAY, KSL and a host of border blasters from Mexico pumped out Top 40 music played by popular disc jockeys. As most smaller, local AM radio stations had to sign off at night, the big 50 kW stations had loyal listeners hundreds of miles away. The popularity of DXing the medium-wave band has diminished as the popular music formats quickly migrated to the clearer, though less propagating, FM radio beginning in the 1970s. Meanwhile, the MW band in the United States was getting more and more crowded with new stations and existing stations receiving FCC authorization to operate at night. In Canada, just the opposite occurred as AM stations began moving to FM beginning in the 1980s and continuing through today. Outside of the Americas and Australia, most AM radio broadcasting was in the form of synchronous networks of government-operated stations, operating with hundreds, even thousands of kilowatts of power. Still, the lower powered stations and occasional trans-oceanic signal were popular DX targets. Especially during wartime and times of conflict, reception of international broadcasters, whose signals propagate around the world on the shortwave bands has been popular with both casual listeners and DXing hobbyists. With the rise in popularity of streaming audio over the internet, many international broadcasters (including the BBC and Voice of America) have cut back on their shortwave broadcasts. An active religious missionary broadcasting scene still makes extensive use of shortwave radio to reach less developed countries around the world. In addition to international broadcasters, the shortwave bands also are home to military communications, RTTY, amateur radio, pirate radio, and the mysterious broadcasts of numbers stations. Many of these signals are transmitted in single side band mode, which requires the use of specialized receivers more suitable to DXing than to casual listening. (Compiled from various sources)DXing means listening to far-away - usually foreign - radio stations. Listening to your regular hometown station is not DXing, but listening to a similar station thousands of kilometers away, outside the normal coverage area, is DXing. "D" is said to mean distance and "X" refers to the unknown. DXers - hobbyists who enjoy DXing - try to pick up radio stations, which normally would not be audible at such a distance. Most DXers concentrate on broadcasting stations. This refers to stations, which are meant to be listened to by the general public. Radio waves are also used by various utility stations from cellphone companies to sea and air traffic as well as the military, and some DXers enjoy hunting these signals as well. DXers should not be confused with radio amateurs - also known as ham operators. Unlike a ham operator, a DXer doesn't transmit anything himself and doesn't therefore need any license. DXers don't need to know about electronics, radio technology nor about telegraphy, but as a hobby DXing can be equally challenging. The challenge lies in picking up radio signals at an incredible distance. In other parts of the world there are still hundreds of radio stations, which no one on your continent has heard, but which could be picked up at your location under ideal conditions - by an experienced DXer, who knows what, where and when to hunt. If you only listen to FM stations, you know that the same stations can be heard day after day. The FM radio signal radiates directly from the transmitter antenna to all directions. Because the earth is round, and the signal doesn't bend, FM radio stations are normally not heard much beyond the horizon. Under exceptional circumstances even an FM signal can bounce back from the atmosphere, and these kind of special reception conditions are what FM DXers are after. Most DXers however are interested in AM (mediumwave) and shortwave stations. If you have listened to the AM band, you know that more stations can be heard during the night than during the day. This is because at night a certain layer in the ionosphere (which is part of the atmosphere) reflects signals back to the earth. Sunlight dissolves this layer, which reappears after dusk. Therefore long distance AM reception is possible only when both the transmitter and the receiver - and the path in between - fall under darkness. Radio propagation on most shortwave frequencies is rather similar. Therefore, around sunset, DXers are eagerly trying to hunt for signals coming from the east. Likewise, sunrise is the best time to hear stations from the west. At these times, interfering stations from other directions are not quite as strong as for example around midnight, when stations from all possible directions are heard and when they can cause interference to each other. Reception conditions change constantly due to a variety of factors, some of which are very unpredictable. Therefore, scoring rare catches requires constant monitoring of the stations audible. DXers use special equipment to monitor the airwaves. The so-called communications receivers are specifically designed for semi-professional listeners. An expensive receiver is however useless without a good antenna. Most DXers use antennas made of copper wire, which is hung on trees or poles outside. After hearing an interesting station, DXers try to identify the station in question. This is often difficult because of poor reception quality. The station may also be transmitting in a language, which the DXer doesn't understand. Over the years DXers develep elementary skills in a wide range of languages and at least learn to recognize different languages, styles of music and identification patterns. Handbooks (especially World Radio TV Handbook), DXers' magazines and websites like DXing.info help in planning what frequencies and when to listen to. For future reference, all interesting signals are recorded. By reviewing notes and recordings made at the time of listening, many DXers compile reception reports, which they send to the station by mail - or nowadays even e-mail. A reception report basically includes all the details of what, where, when and how the station was heard by the distant listener. Written program details or a cassette recording should be enclosed as proof of having heard the station. In the report, DXers request a confirmation in return - a letter or a "QSL" card from the station verifying that the signal was indeed theirs. In the past reception reports used to be valuable feedback for international broadcasters, but nowadays when monitoring reception quality is in many causes automated and more professional, many stations find themselves inundated with letters that are not much use, and reply just out of courtesy. DXers collect these verifications - known as QSLs - as mementos of their discoveries on the dial, and also to demonstrate how many stations they have been able to pick up. Even though QSLs can't be considered as definite evidence of hearing a station - as some stations routinely confirm even insufficient reports and other stations hardly ever reply to any reports - collecting QSLs remains a major pursuit for many DXers. Competitions between DXers are usually based on the number of QSLs received. (Mika Mäkeläinen, “Introduction to DXing”)
French comment : Le DXing est une passion qui consiste à rechercher et identifer des signaux radio/tv à longues distance, ou à établir des contacts bilatéraux avec des stations distantes sur les bandes radioamateurs ou sur les bandes libres(CB,pmr446,...). Bien souvent le DXer (celui qui pratique le DXing) fait également la "chasse" aux cartes qsl, sorte de carte postal servant à confirmer une liaison ou une réception. Le nom de ce hobby vient de "DX" une abréviation télégraphique pour "distance". (Compiled from various sources)
Urls : http://www.dxing.info/introduction.dx (last visited ) http://pl703.pairlitesite.com/history.html (last visited )

No comment for this page

Leave a comment