Portable radios are limited in the power at which they can transmit, usually somewhere between .5 watts and 5 watts. A very rough rule of thumb is that one watt equals one mile of range over flat and open terrain. Buildings and mountains will, of course, greatly modify effective range. When two radios communicate directly …
A multivibrator is a device that changes between two states and its own design or an external force powers it. For example, a weight that is placed on a suspended spring will extend the spring to its maximum length as gravity weighs down on it. When the spring is stretched to its maximum length, however, …
A projector lamp is used to transfer an image from a multimedia projector onto a larger screen. Earlier halogen bulbs were used for many years for projection purposes, but were discontinued as halogen produced a yellow tone on the images. A projector lamp relies on an intense light bulb, called a metal halide bulb, to …
A spark-gap transmitter is a mechanism for producing radio signals. It has been the primary radio transmission device during the early years of radio technology. It was soon superseded by other transmitters due to its discontinuous radio wave production and widely varying frequencies. How a Spark-Grap Transmitter Works A spark gap transmitter is basically composed …
More properly known as the Bayonet Neill-Concelman connector, the BNC connector is one of several radio frequency connectors on the market today. The name of the connector is derived from a combination of two things: 1) the connecting technology employed; and 2) the names of the two inventors of the device. Paul Neill of Bell …
MIL-C-5015, now known popularly as MS connectors, are multi-pin, highly durable connectors that were originally invented for use in military applications. They have a variety of features that makes them easy to use for nearly any application and are often found in a variety of advanced, high power, heavy duty devices in the industrial world. …
Pulse Code Modulation (PCM) was pioneered by the British engineer Alec Reeves in 1937. The first transmission of a message using PCM was the SIGSALY voice encryption equipment used in high-level Allied communications during World War II starting in 1943. The original primary application for PCM was to convert analog signals into digital format by …
GPS – A Short Introduction GPS, which stands for Global Positioning System, is a satellite navigation system that can ascertain the latitude and longitude of a GPS receiver device on the Earth. The GPS consists of more than two dozen global positioning satellites orbiting the earth. Each satellite transmits radio signals, which can help determine …
Satellite radio refers to a number of subscription-based radio broadcasting programs that are available in the US, Europe, and elsewhere that are dependent on satellites to provide mobile users with constant radio access. While terrestrial-based FM radio stations only provide radio broadcasts to a specific area, usually confined to the city they are located in, …
An opto isolator is an electronic device that prevents high voltages from components in one side of a circuit from damaging or interfering with components on the other side of the same circuit. Opto isolators regulate voltage levels by converting electricity into a beam of light. This prevents voltage spikes from impacting more than a single …