DXing

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DXing, taken from DX, the telegraphic shorthand for "distance" or "distant", [1] 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".

Contents

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. [2] [3]

Types

AM radio DX

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, WGY, 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 were able to reach 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, with low power, at night—this largely peaked in the conservative talk radio boom of the 1990s, and especially since the 2010s, the AM band has gone into decline. In Canada, the decline came sooner as AM stations began moving to FM beginning in the 1980s and continuing through today. A limited number of music stations, including WSM in the United States, CFZM in Canada and—on weekends—WABC still program music on their clear-channel signals.

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. [4]

Shortwave DX

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 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. [5]

VHF DXing

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, [6] and European TV signals have been received on the West Coast of the U.S. [7]

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.[ citation needed ]

Amateur radio DX

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. [8]

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. [9] For award purposes, entities/areas other than nation-states (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. [8] 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.

DX clubs

Many radio enthusiasts are members of DX clubs in many countries around the world. The clubs are a useful source of information about news relating to international radio, as well as an opportunity to socialize. [10] [11] One example is the British DX Club . [12]

QSL cards

QSL card from Voice of America QSL-VOA-Thessaloniki-1972.jpg
QSL card from Voice of America

A number of DXers collect acknowledgement cards called QSL cards. QSL cards often have a picture and messages indicating their country's culture or technological life on one side, and confirmation of the listeners reception data on the other.

SINPO report

SINPO is a code used to indicate reception quality in each of five attributes, graded on a scale of 1 to 5, where '1' means the quality was very bad and '5' very good. The attributes are:

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

Reports are sent by post or email, and may include the listeners geographical location 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, and suggestions if any.

Although the SINPO code is a subjective measure, a particular broadcast may receive SINPO reports from several listeners from the same area, allowing the broadcaster to compare reports and gain insight into signal coverage.

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

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. [13] On the low frequency bands (30 kHz to 30 MHz), contacts between stations separated by more than 100 miles are often considered DX, [14] but in amateur radio on the high-frequency bands, DX is referred to as stations outside of the receiver's country (see the section, Amateur radio 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 decreases 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 9,835 miles (15,827 kilometers).[ citation needed ]

DXing equipment

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. Car radios are also used for DXing the AM broadcast bands.

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. In general, an inexpensive 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 is that 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.

Enthusiasts utilize personal computers alongside radio control software tailored for FM reception, such as XDR-GTK, specifically designed for use with devices like the Sony XDR F1HD and NXP TEF668x-based receivers. This software utilizes the connection and simultaneous control of multiple radio receivers. Additionally, tools like FM-DX Webserver, accessible directly through a web browser, further enhance the experience for FM & AM enthusiasts. These setups enable hobbyists to engage in diversity reception, allowing for comprehensive "A to B" comparisons of various antennas and receivers to optimize signal reception, along with the option to scan remotely.

Many simple wire antennas can be made inexpensively. Having 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.

See also

Related Research Articles

<span class="mw-page-title-main">Shortwave radio</span> Radio transmissions using wavelengths between 10 m and 100 m

Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz ; above the medium frequency band (MF), to the bottom of the VHF band.

<span class="mw-page-title-main">Medium frequency</span> The range 300-3000 kHz of the electromagnetic spectrum

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 hectometers. Frequencies immediately below MF are denoted as 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.

<span class="mw-page-title-main">Longwave</span> Radio transmission using wavelengths above 1000 m

In radio, longwave, long wave or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band. The term is historic, dating from the early 20th century, when the radio spectrum was considered to consist of longwave (LW), medium-wave (MW), and short-wave (SW) radio bands. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.

<span class="mw-page-title-main">Radio broadcasting</span> Transmission by radio waves intended to reach a wide audience

Radio broadcasting is the broadcasting of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio station, while in satellite radio the radio waves are broadcast by a satellite in Earth orbit. To receive the content the listener must have a broadcast radio receiver (radio). Stations are often affiliated with a radio network that provides content in a common radio format, either in broadcast syndication or simulcast, or both. The encoding of a radio broadcast depends on whether it uses an analog or digital signal. Analog radio broadcasts use one of two types of radio wave modulation: amplitude modulation for AM radio, or frequency modulation for FM radio. Newer, digital radio stations transmit in several different digital audio standards, such as DAB, HD radio, or DRM.

<span class="mw-page-title-main">R-S-T system</span> Brevity code for Ham radio signal reports

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.

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."

<span class="mw-page-title-main">Skywave</span> Propagation of radio waves beyond the radio horizon.

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.

<span class="mw-page-title-main">DX-pedition</span> Amateur radio "expedition"

A DX-pedition is an expedition to what is considered an exotic place by amateur radio operators and DX listeners, typically 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 that comprises 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 with a line-of-sight range of about 100 miles (160 km).

<span class="mw-page-title-main">Shortwave listening</span> Hobby of listening to shortwave radio

Shortwave listening, or SWLing, is the hobby of listening to shortwave radio broadcasts located on frequencies between 1700 kHz and 30 MHz (30 000 kHz). Listeners range from casual users seeking international news and entertainment programming, to hobbyists immersed in the technical aspects of long-distance radio reception and sending and collecting official confirmations that document their reception of remote 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 6.05 MHz (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.

SINPO, an acronym for Signal, Interference, Noise, Propagation, and Overall, is a Signal Reporting Code used to describe the quality of broadcast and 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.

<span class="mw-page-title-main">Amateur radio operating award</span> Award

An amateur radio operating award is earned by an amateur radio operator for establishing two-way communication with other amateur radio stations. Awards are sponsored by national amateur radio societies, radio enthusiast magazines, or amateur radio clubs, and aim to promote activity on the amateur radio bands. Each award has its own set of rules and fees. Some awards require the amateur radio operator to have contacted other stations in a certain number of countries, Maidenhead grid locators, or counties. Because amateur radio operators are forbidden by regulation to accept financial compensation for their on-air activity, award recipients generally only receive a certificate, wooden plaque, or a small trophy as recognition of their award.

<span class="mw-page-title-main">QSL card</span> Amateur radio transmission confirmation card

A QSL card is a written confirmation of either a two-way radiocommunication between two amateur radio or citizens band stations; a one-way reception of a signal from an AM radio, FM radio, television or shortwave broadcasting station; or 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:

F2 propagation (F2-skip) is the reflection of VHF signals off the F2 layer of the ionosphere. The phenomenon is rare compared to other forms of propagation but can reflect signals thousands of miles beyond their intended broadcast area, substantially farther than E-skip. F2-skip affects the upper ends of the high frequency (HF) spectrum and the low ends of the very high frequency (VHF) spectrum; only a small portion of F2's effective range overlaps frequencies used by consumer broadcast reception, also contributing to the phenomenon being rarely encountered.

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.

<span class="mw-page-title-main">Shortwave radio receiver</span> Shortwave radio

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.

References

  1. ↑ Mika Mäkeläinen. "Introduction To DXing". DXing.info. Retrieved November 12, 2016.
  2. ↑ Jerome S. Berg (30 October 2008). Listening on the Short Waves, 1945 to Today. McFarland. pp. 330–. ISBN   978-0-7864-3996-6 . Retrieved November 12, 2016.
  3. ↑ Susan J. Douglas (25 February 2004). Listening in: radio and the American imagination. U of Minnesota Press. pp. 73–. ISBN   978-0-8166-4423-0 . Retrieved November 12, 2016.
  4. ↑ "AM Band DXing". www.dxing.com.
  5. ↑ "Introduction to DXing :: DXing.info". www.dxing.info.
  6. ↑ Hattam, Mark. "Trans-Atlantic FM". dxradio.co.uk. DX Radio. Retrieved 1 May 2018.
  7. ↑ Radio-electronics. Gernsback Publications. 1959.
  8. 1 2 Danny Gregory; Paul Sahre (1 April 2003). Hello world: a life in ham radio. Princeton Architectural Press. pp. 217–. ISBN   978-1-56898-281-6 . Retrieved 4 April 2012.
  9. ↑ ARRL DXCC List, 2007 backup: DXCC List – ARRL
  10. ↑ AMARAL, Cristiano Torres (2021). Guia Moderno do Radioescuta. Brasília: Amazon. p. 333. ISBN   978-65-00-20800-9.
  11. ↑ Wilson, Mark J. (2007). The ARRL Operating Manual for Radio Amateurs. American Radio Relay League, 2007. ISBN   9780872591097 . Retrieved 8 July 2023.
  12. ↑ O'Grady, Paul. "Free sample of British DX Club (BDXC)". www.radioenthusiast.co.uk. Radio Enthusiast. Retrieved 8 July 2023.
  13. ↑ H. Ward Silver (2008). The ARRL Extra Class License Manual for Ham Radio. American Radio Relay League. pp. 2–. ISBN   978-0-87259-135-6.
  14. ↑ 73 Amateur Radio. WGE Pub. 1988.
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