A speaker is a device that converts electrical signals into actual sound. Speakers accomplish this by using a magnetic reader or antenna to receive an electrical signal from a radio station or magnetic storage device.

MSK (Minimum Shift Keying) is a type of continuous frequency shift modulation that is used to transfer radio signals from satellites and radio broadcasting to mobile devices and vice versa. Unlike other forms of frequency modulation, MSK produces a half sine wave that limits problems associated with non-linear distortion.

Pulse position modulation is a signal modulation technique that allows computers to share data by measuring the time each data packet takes to reach the computer. It is often used in optical communication, such as fiber optics, in which there is little multi-pathway interference.

A fractal antenna is a diamond-shaped antenna that maximizes the total amount of material within a given amount of space that transmits or receives electromagnetic waves. Fractal antennas do this by making each section of the antenna its own separate dipole.

VSWR (Voltage Standing Wave Ratio) is a metric commonly used with antenna systems for ham or shortwave radio communication. VSWR is normally defined as a ratio with a 1:1 VSWR, indicating that there is an exact or perfect match between all antenna system elements. The VSWR can also be expressed by comparing Vmax with Vmin in a ratio.

An attic antenna is one that is mounted inside of an attic in order to provide maximum range as well as protection from rain, snow, sun, wind, and animals. Attic antennas are rather common and provide quality reception for those who live in rural areas, away from most radio transmitters.

A loop antenna is one that is designed to receive radio signals more efficiently than other antennas. Loop antennas are considered more efficient than others because they are mobile, work with a wide range of frequencies, and use less electricity.

A circulator is a box-shaped ferrite device that has three or four ports and allows energy from one port to transfer to the next port in line. Circulators are usually used with radio signals but can also be used with microwaves, light, and other electromagnetic waves.

Standing Wave Ratio (SWR) meters are used to measure the standing wave ratio in a communications transmission line. The meter can display how much a transmission line and the load are mismatched (normally a radio antenna). It also determines how effective the impedance is of matching efforts.