Amateur radio in the context of "Two-way radio"

Broadcasting is the distribution of audio and audiovisual content to dispersed audiences via an electronic mass communications medium, typically using the electromagnetic spectrum (radio waves), in a one-to-many model. Broadcasting began with AM radio, which became popular around 1920 with the spread of vacuum tube radio transmitters and receivers. Before this, most implementations of electronic communication (early radio, telephone, and telegraph) were one-to-one, with the message intended for a single recipient. The term broadcasting evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing the widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898.

Over-the-air broadcasting is usually associated with radio and television, though more recently, both radio and television transmissions have begun to be distributed by cable (cable television). The receiving parties may include the general public or a relatively small subset; the point is that anyone with the appropriate receiving technology and equipment (e.g., a radio or television set) can receive the signal. The field of broadcasting includes both government-managed services such as public radio, community radio and public television, and private commercial radio and commercial television. The U.S. Code of Federal Regulations, title 47, part 97 defines broadcasting as "transmissions intended for reception by the general public, either direct or relayed". Private or two-way telecommunications transmissions do not qualify under this definition. For example, amateur ("ham") and citizens band (CB) radio operators are not allowed to broadcast. As defined, transmitting and broadcasting are not the same.

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" (see DXing).

Modern Electrics was a technical magazine for the amateur radio experimenter. The magazine existed between 1908 and 1914.

Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).

VHF radio waves propagate mainly by line-of-sight, so they are blocked by hills and mountains, although due to refraction they can travel somewhat beyond the visual horizon out to about 160 km (100 miles). Common uses for radio waves in the VHF band are Digital Audio Broadcasting (DAB) and FM radio broadcasting, television broadcasting, two-way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometers with radio modems, amateur radio, and marine communications. Air traffic control communications and air navigation systems (e.g. VOR and ILS) work at distances of 100 kilometres (62 miles) or more to aircraft at cruising altitude.

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.

As a result of skywave propagation, a signal from a distant AM broadcasting station, a shortwave station, or – during sporadic E propagation conditions (principally during the summer months in both hemispheres) – a distant VHF FM or TV station can sometimes be received as clearly as local stations. Most long-distance shortwave (high frequency) radio communication – between 3 and 30 MHz – is a result of skywave propagation. Since the early 1920s amateur radio operators (or "hams"), limited to lower transmitter power than broadcast stations, have taken advantage of skywave for long-distance (or "DX") communication.

Radio News was an American monthly technology magazine published from 1919 to 1971. The magazine was started by Hugo Gernsback as a magazine for amateur radio enthusiasts, but it evolved to cover all the technical aspects to radio and electronics. In 1929, a bankruptcy forced the sale of Gernsback's publishing company to B. A. Mackinnon. In 1938, Ziff-Davis Publishing acquired the magazines.