DXing is the hobby of receiving 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 obtain written verifications of reception or contact, sometimes referred to as "QSLs" or "veries". The name of the hobby comes from DX, telegraphic shorthand for "distance" or "distant".
Radio is the technology of using radio waves to carry information, such as sound and images, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.
Terrestrial television is a type of television broadcasting in which the television signal is transmitted by radio waves from the terrestrial (Earth-based) transmitter of a television station to a TV receiver having an antenna. The term terrestrial is more common in Europe and Latin America, while in the United States it is called broadcast or over-the-air television (OTA). The term "terrestrial" is used to distinguish this type from the newer technologies of satellite television, in which the television signal is transmitted to the receiver from an overhead satellite, and cable television, in which the signal is carried to the receiver through a cable.
Amateur radio, also known as ham radio, describes the use of radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communication. The term "amateur" is used to specify "a duly authorised person interested in radioelectric practice with a purely personal aim and without pecuniary interest;" and to differentiate it from commercial broadcasting, public safety, or professional two-way radio services.
The practice of DXing arose during the early days of radio broadcasting. Listeners would mail "reception reports" to radio broadcasting stations in hopes of getting a written acknowledgement or a QSL card that served to officially verify they had heard a distant station. Collecting these cards became popular with radio listeners in the 1920s and 1930s, and reception reports were often used by early broadcasters to gauge the effectiveness of their transmissions. Although international shortwave broadcasts are on the decline, DXing remains popular among dedicated shortwave listeners. The pursuit of two-way contact between distant amateur radio operators is also a significant activity within the amateur radio hobby.
Radio broadcasting is transmission by radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both. The signal types can be either analog audio or digital audio.
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.
North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere; it is also considered by some to be a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.
KDKA is a Class A radio station, owned and operated by Entercom and licensed to Pittsburgh, Pennsylvania. Its studios are located at the combined Entercom Pittsburgh facility in the Foster Plaza on Holiday Drive in Green Tree, and its transmitter site is at Allison Park. The station's programming is also carried over KDKA-FM's 93.7 HD2 digital subchannel.
WLW, branded "Newsradio 700 WLW", is a commercial news/talk radio station serving Greater Cincinnati. Owned by iHeartMedia, the station's studios are located in Sycamore Township, and its transmitter is at Mason, Ohio. One of the oldest radio stations in the United States, in the 1930s it was also the only U.S. station ever authorized to broadcast with a power of 500,000 watts.
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.
Popular music is music with wide appeal that is typically distributed to large audiences through the music industry. These forms and styles can be enjoyed and performed by people with little or no musical training. It stands in contrast to both art music and traditional or "folk" music. Art music was historically disseminated through the performances of written music, although since the beginning of the recording industry, it is also disseminated through recordings. Traditional music forms such as early blues songs or hymns were passed along orally, or to smaller, local audiences.
The United States of America (USA), commonly known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.
The Federal Communications Commission (FCC) is an independent agency of the United States government created by statute to regulate interstate communications by radio, television, wire, satellite, and cable. The FCC serves the public in the areas of broadband access, fair competition, radio frequency use, media responsibility, public safety, and homeland security.
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. Missionary religious broadcasters still make 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.
Though sporadic in nature, signals on the FM broadcast and VHF television bands - especially those stations at the lower end of these bands - can "skip" for hundreds, even thousands of miles. North American FM stations have been received in Western Europe,and European TV signals have been received on the West Coast of the U.S.
Police, fire, and military communications on the VHF bands are also DX'ed to some extent on multi-band radio scanners, though they are mainly listened to strictly on a local basis. One difficulty is in identifying the exact origins of communications of this nature, as opposed to commercial broadcasters which must identify themselves at the top of each hour, and can often be identified through mentions of sponsors, slogans, etc. throughout their programming.
Amateur radio operators who specialize in making two way radio contact with other amateurs in distant countries are also referred to as "DXers". On the HF (also known as shortwave) amateur bands, DX stations are those in foreign countries. On the VHF/UHF amateur bands, DX stations can be within the same country or continent, since making a long-distance VHF contact, without the help of a satellite, can be very difficult. DXers collect QSL cards as proof of contact and can earn special certificates and awards from amateur radio organizations.
In addition, many clubs offer awards for communicating with a certain number of DX stations. For example, the ARRL offers the DX Century Club award, or DXCC. The basic certificate is awarded for working and confirming at least 100 entities on the ARRL DXCC List.For award purposes, other areas than just political countries can be classified as "DX countries". For example, the French territory of Reunion Island in the Indian Ocean is counted as a DX country, even though it is a region of France. The rules for determining what is a DX country can be quite complex and to avoid potential confusion, radio amateurs often use the term entity instead of country. In addition to entities, some awards are based on island groups in the world's oceans. On the VHF/UHF bands, many radio amateurs pursue awards based on Maidenhead grid locators.
In order to give other amateurs a chance to confirm contacts at new or exotic locations, amateurs have mounted DXpeditions to countries or regions that have no permanent base of amateur radio operators.There are also frequent contests where radio amateurs operate their stations on certain dates for a fixed period of time to try to communicate with as many DX stations as possible.
Many radio enthusiasts are members of DX clubs. There are many DX clubs in many countries around the world. They are useful places to find information about up-to-date news relating to international radio. Many people also enjoy social events, which can form a large part of the enjoyment that people can get out of the radio hobby.
One of the interesting sides of DXing as a hobby is collecting QSL cards (acknowledgement cards from the broadcaster) confirming the listener's reception report (sometimes called SINPO report, see next section).
Usually a QSL card will have a picture on one side and the reception data on the other. Most of the broadcasters will use pictures and messages indicating their country's culture or technological life.
SINPO stands for the following qualities, graded on a scale of 1 to 5, where '1' means the quality was very bad and '5' very good.
S - Signal strength
I - Interference with other stations or broadcasters
N - Noise ratio in the received signal
P - Propagation (ups and downs of the reception)
O - Overall merit
Although this is a subjective measure, with practise the grading becomes more consistent, and a particular broadcast may be assessed by several listeners from the same area, in which case the broadcaster could assess correspondence between reports.
After listening to a broadcast, the listener writes a report with SINPO values, typically including his geographical location (called QTH in amateur radio terminology) in longitude and latitude, the types of receiver and antennae used, the frequency the transmission was heard on, a brief description of the programme listened to, their opinion about it, suggestions if any, and so on.
The listener can send the report to the broadcaster either by post or email, and request verification (QSL) from them.
Variants of this report are: a) the SIO report which omits the Noise and Propagation, b) grading on a scale of 1 to 3 (instead of 1 to 5) and c) the SINFO report where the F stands for fading.
DX communication is communication over large or relatively uncommon distances. On the UHF or VHF bands which are typically used for short range or line of sight communications, DX may represent communication with stations 50 or 100 miles away. The UHF and microwave bands have also been used to accomplish Earth–Moon–Earth communication between stations worldwide.On the low frequency bands (30 to 300 kHz), contacts between stations separated by more than 100 miles are often considered DX.
Among amateur radio operators and shortwave listeners, most traditional DX communication occurs on the HF bands, where the ionosphere is used to refract the transmitted radio beam. The beam returns to the Earth's surface, and may then be reflected back into the ionosphere for a second bounce. Ionospheric refraction is generally only feasible for frequencies below about 50 MHz, and is highly dependent upon atmospheric conditions, the time of day, and the eleven-year sunspot cycle. It is also affected by solar storms and some other solar events, which can alter the Earth's ionosphere by ejecting a shower of charged particles.
The angle of refraction places a minimum on the distance at which the refracted beam will first return to Earth. This distance increases with frequency. As a result, any station employing DX will be surrounded by an annular dead zone where they can't hear other stations or be heard by them.
This is the phenomenon that allows short wave radio reception to occur beyond the limits of line of sight. It is utilized by amateur radio enthusiasts (hams), shortwave broadcast stations (such as BBC and Voice of America) and others, and is what allows one to hear AM (MW) stations from areas far from their location. It is one of the backups to failure of long distance communication by satellites, when their operation is affected by electromagnetic storms from the sun.
For example, in clear ionosphere conditions, one can hear France Inter on 711 kHz, far into the UK and as far as Reading, Berkshire. It is also possible to hear Radio Australia from Melbourne as far away as Lansing, Michigan, a distance of some 9835 miles (15,827 kilometers).
Radio equipment used in DXing ranges from inexpensive portable receivers to deluxe equipment costing thousands of dollars. Using just a simple AM radio, one can easily hear signals from the most powerful stations propagating hundreds of miles at night. Even inexpensive shortwave radio receivers can receive signals emanating from several countries during any time of day.
Serious hobbyists use more elaborate receivers designed specifically for pulling in distant signals, and often build their own antennas designed for a specific frequency band. There is much discussion and debate in the hobby about the relative merits of lesser priced shortwave receivers vs. their multi-thousand dollar "big brother" radios. In general, a good desktop or "PC Radio" will be able to "hear" just about what a very expensive high-performance receiver can receive. The difference between the two types comes into play during difficult band or reception conditions. The expensive receiver will have more filtering options and usually better adjacent channel interference blocking, sometimes resulting in the difference of being able to receive or not receive a signal under poor conditions. Reception of international broadcasting seldom shows a noticeable difference between the two radios. Car radios are also used for DXing the broadcast bands.
Another recent[ when? ] trend is for the hobbyist to employ multiple radios and antennas connected to a personal computer. Through advanced radio control software, the radios can be automatically ganged together, so that tuning one radio can tune all the others in the group. This DXing technique is sometimes referred to as diversity reception and facilitates easy "A to B" comparison of different antennas and receivers for a given signal. For more details on "PC Radios" or computer controlled shortwave receivers see the discussion in Shortwave listening.
Having a minimum of two dipole antennas at right angles to each other (for example, one running north–south and one running east–west) can produce dramatically different reception patterns. These simple antennas can be made for a few dollars worth of wire and a couple of insulators.
Shortwave radio is radio transmission using shortwave radio frequencies. There is no official definition of the band, but the range always includes all of the high frequency band (HF), and generally extends from 1.7–30 MHz (176.3–10.0 m); from the high end of the medium frequency band (MF) just above the mediumwave AM broadcast band, to the end of the HF band.
Medium wave (MW) is the part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz, using channels spaced every 9 kHz, and in North America an extended MW broadcast band ranges from 525 kHz to 1705 kHz, using 10 kHz spaced channels. The term is a historic one, dating from the early 20th century, when the radio spectrum was divided on the basis of the wavelength of the waves into long wave (LW), medium wave, and short wave (SW) radio bands.
Medium frequency (MF) is the ITU designation for radio frequencies (RF) in the range of 300 kilohertz (kHz) to 3 megahertz (MHz). Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hectometer band as the wavelengths range from ten to one hectometer. Frequencies immediately below MF are denoted low frequency (LF), while the first band of higher frequencies is known as high frequency (HF). MF is mostly used for AM radio broadcasting, navigational radio beacons, maritime ship-to-shore communication, and transoceanic air traffic control.
The R-S-T system is used by amateur radio operators, shortwave listeners, and other radio hobbyists to exchange information about the quality of a radio signal being received. The code is a three digit number, with one digit each for conveying an assessment of the signal's readability, strength, and tone. The code was developed in 1934 by Amateur radio operator Arthur W. Braaten, W2BSR, and was similar to that codified in the ITU Radio Regulations, Cairo, 1938.
The DX Century Club, or DXCC, is an amateur radio operating award earned by making and confirming contacts with licensed amateur operators in at least 100 "countries" around the world, many of which are physically distant from the claimant.
TV DX and FM DX is the active search for distant radio or television stations received during unusual atmospheric conditions. The term DX is an old telegraphic term meaning "long distance."
In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvature of the Earth, skywave propagation can be used to communicate beyond the horizon, at intercontinental distances. It is mostly used in the shortwave frequency bands.
A DX-pedition is an expedition to what is considered an exotic place by amateur radio operators, perhaps because of its remoteness, access restrictions or simply because there are very few radio amateurs active from that place. This could be an island, a country, or even a particular spot on a geographical grid. "DX" is a telegraphic shorthand for "distance" or "distant".
The 2-meter amateur radio band is a portion of the VHF radio spectrum, comprising frequencies stretching from 144 MHz to 148 MHz in International Telecommunication Union region (ITU) Regions 2 and 3 and from 144 MHz to 146 MHz in ITU Region 1. The license privileges of amateur radio operators include the use of frequencies within this band for telecommunication, usually conducted locally within a range of about 100 miles (160 km).
Shortwave listening, or SWLing, is the hobby of listening to shortwave radio broadcasts located on frequencies between 1700 kHz and 30 MHz. Listeners range from casual users seeking international news and entertainment programming, to hobbyists immersed in the technical aspects of radio reception and collecting official confirmations that document their reception of distant broadcasts (DXing). In some developing countries, shortwave listening enables remote communities to obtain regional programming traditionally provided by local medium wave AM broadcasters. In 2002, the number of households that were capable of shortwave listening was estimated to be in the hundreds of millions.
HCJB, "The Voice of the Andes", was the first radio station with daily programming in Ecuador and the first Christian missionary radio station in the world. The station was founded in 1931 by Clarence W. Jones, Reuben Larson, and D. Stuart Clark. HCJB now focuses on Ecuador with unified programming on FM at 89.3 MHz in Pichincha, at 92.5 MHz in Manabí, at 96.1 MHz in Tungurahua and Cotopaxi, at 98.3 MHz in Esmeraldas and with separate programming on AM at 690 kHz. Broadcasts in Spanish and indigenous languages on 6050 kHz (1 kW), continue on an intermittent basis with a new solid state transmitter which in 2017 replaced an older (5 kW) transmitter. These broadcasts were not listed on the HCJB English website as of February 2016.
Contesting is a competitive activity pursued by amateur radio operators. In a contest, an amateur radio station, which may be operated by an individual or a team, seeks to contact as many other amateur radio stations as possible in a given period of time and exchange information. Rules for each competition define the amateur radio bands, the mode of communication that may be used, and the kind of information that must be exchanged. The contacts made during the contest contribute to a score by which stations are ranked. Contest sponsors publish the results in magazines and on web sites.
SINPO, an acronym for Signal, Interference, Noise, Propagation, and Overall, is a Signal Reporting Code used to describe the quality of radiotelegraph transmissions. SINPFEMO, an acronym for Signal, Interference, Noise, Propagation, frequency of Fading, dEpth, Modulation, and Overall is used to describe the quality of radiotelephony transmissions. SINPFEMO code consists of the SINPO code plus the addition of three letters to describe additional features of radiotelephony transmissions. These codes are defined by Recommendation ITU-R Sm.1135, SINPO and SINPFEMO codes.
MW DX, short for mediumwave DXing, is the hobby of receiving distant mediumwave radio stations. MW DX is similar to TV and FM DX in that broadcast band (BCB) stations are the reception targets. However, the nature of the lower frequencies used by mediumwave radio stations is very much different from that of the VHF and UHF bands used by FM and TV broadcast stations, and therefore involves different receiving equipment, signal propagation, and reception techniques.
Amateur radio frequency allocation is done by national telecommunication authorities. Globally, the International Telecommunication Union (ITU) oversees how much radio spectrum is set aside for amateur radio transmissions. Individual amateur stations are free to use any frequency within authorized frequency ranges; authorized bands may vary by the class of the station license.
A QSL card is a written confirmation of either a two-way radiocommunication between two amateur radio stations or a one-way reception of a signal from an AM radio, FM radio, television or shortwave broadcasting station. It can also confirm the reception of a two-way radiocommunication by a third party listener. A typical QSL card is the same size and made from the same material as a typical postcard, and most are sent through the mail as such.
A reception report is a means by which radio stations receive detailed feedback from their listeners about the quality and content of their broadcasts. A reception report consists of several pieces of information which help the station verify that the report confirms coverage of their transmission, and usually include the following information:
The E layer of the ionosphere is not the only layer that can reflect VHF television signals. Less frequently, the higher F2 layer can also propagate VHF signals several thousand miles beyond their intended area of reception.
Tropospheric propagation describes electromagnetic propagation in relation to the troposphere. The service area from a VHF or UHF radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. Viewers living in such a "deep fringe" reception area will notice that during certain conditions, weak signals normally masked by noise increase in signal strength to allow quality reception. Such conditions are related to the current state of the troposphere.
A shortwave radio receiver is a radio receiver that can receive one or more shortwave bands, between 1.6 and 30 MHz. A shortwave radio receiver often receives other broadcast bands, such as FM radio, Longwave and Mediumwave. Shortwave radio receivers are often used by dedicated hobbyists called shortwave listeners.