Medium Wave DXing Guide @ DXing Info

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MW DX

short for mediumwave DXing

the hobby of receiving, or simply the reception of distant mediumwave (known outside radio circles as "AM radio" in North America) 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 (530 - 1700 kHz) 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.

MW Propagation

During the daytime, medium and high powered mediumwave AM radio stations have a normal reception range of about 20 to 250 miles (32 to 400+ km), depending on the transmitter power, location, and the quality of the receiving equipment, including the amount of man-made and natural electromagnetic noise present. Long-distance reception is normally impeded by the D layer of the ionosphere, which during the daylight hours absorbs signals in the mediumwave range.

When sun sets, the D-Layer dissipates, allowing Medium Wave radio waves from such stations to bounce off the ionosphere, producing reliable, long distance reception of (especially) high-powered stations up to about 1,200 miles (2,000 km) away on a nightly basis. Aside from the more or less regular reception of certain high powered transmitters, variable conditions allow reception of different stations at different times - for example, on one night a medium-powered broadcaster from Cleveland, Ohio may be audible in Duluth, but not on the following night. Much of the hobby consists in trying to receive and log as many of these stations as possible, identifying target stations and frequencies to listen to and log.

Near or on the coastlines, trans-oceanic reception is quite common and a favored target of DXers in those areas. Very distant inter-continental DX from stations several thousands of kilometers distant is possible even far inland, but may require exceptionally good conditions and a good receiver and antenna on the listening side.

DX stations evaporate from the dial as the sun rises. However, sunrise and sunset ("SRS" and "SSS") periods can provide interesting loggings?  

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Regional MW DX

MW DX in Europe & North America

Stations in Europe often run higher power than American stations, sometimes several hundreds of kilowatts. Synchronous networks are also commonly used, with local transmitter stations often having less of an identity than those in the United States and Canada. The wide variety of languages spoken over the DX'ing range, from Spanish to Arabic to Estonian, adds an element of challenge to DXing in the region. Some stations in Europe have taken to Digital Radio Mondiale transmissions, requiring a receiver capable of demodulating such signals, or a computer loaded with special software coupled to the receiver.

DX reception of North American stations has been observed on many occasions. CJYQ (St. John's, Newfoundland and Labrador) 930 kHz is regarded as the easiest to receive, and its presence is taken as an indication that the reception of more distant stations is possible. North American stations whose frequencies are furthest from the 9 kHz multiples used in Europe are easier to receive, particularly since 24-hour broadcasting is now the norm in Europe.  

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MW Equipments

While any radio covering the mediumwave (AM radio) band can be used for DX purposes, serious DXers generally invest in a higher-quality receiver, and often a specialised indoor tuned box loop or outdoor longwire antenna. At the lower end of the spectrum, a portable radio with its own internal ferrite core antenna designed for long-distance AM radio reception may be used, such as the venerable Indian Made Philips (starts at $4) or German Grundig or Asian Sony. More serious DXers may upgrade to a high-quality shortwave communications receiver with good performance on the lower mediumwave frequencies, such as the Drake R8 or AOR 7030+. In such a configuration, a high-performance indoor loop or outdoor longwire antenna, sometimes many hundreds of meters long, depending on space availability, is normally used. For trans-Atlantic or trans-Pacific reception, where the target station is on a 9 kHz rather than a 10 kHz multiple or vice versa, receivers with narrow RF filters are useful in order to exclude adjacent broadcasts on the listener's own continent. To combat noise, DXers may use an outboard noise attenuation device, or a radio with built-in digital signal processing capabilities. A personal computer with specialized logging software or simply a paper notebook is used to write logs. Tape recorders can be used to archive memorable DX moments, or identify hard-to-hear station receptions after the fact.