CB (Citizens Band) Radio is an unlicensed service. CB Radio consists of 40 HF channels on AM and SSB. Channel 9 is designated for emergencies and assistance. The maximum allowable power for a CB radio is 5 watts. Repeaters are not allowed on CB radio. CB Radio Usage CB Radio is mainly utilized by truck drivers. CB radio is known for the colorful language utilized by its adherents, such as "10-4 good buddy". CB Radio Frequencies Channel Frequency 1 26.965 2 26.975 3 26.985 4 27.005 5 27.015 6 27.025 Read More

Reed-Solomon is an algorithm for Forward Error Correction (FEC). Reed-Solomon was introduced by Irving S. Reed and Gustave Solomon of MIT Labs in Polynomial Codes Over Certain Finite Fields, which was published in the Journal of the Society for Industrial and Applied Mathematics in 1960. Reed-Solomon does not specify a block size or a specific number of check symbols. These variables can be set to the best variables for each transmission medium. DVB uses Reed Solomon coding configured to use blocks of 188 information symbols and 16 check symbols, which Read More

A multivibrator is a device that switches between two states. It is a type of oscillator and can be used as a trigger, converter, moderator, or divider. It usually produces changes in a system at timed intervals, depending on the number and placement of resistors and other elements within the system as well as the input signal’s intensity. An astable multivibrator is a multivibrator that does not rest in an unstable state like other multivibrators, but continuously switches between two states. How an Astable Multivibrator Works Astable multivibrators switch between Read More

UHF is an acronym for a band of radio frequencies often used to broadcast television signals. Mobile phones and satellite radio also use UHF signals. The letters ‘UHF’ stand for: Ultra High Frequency. UHF Frequencies Any radio frequency between 300 MegaHertz (MHz) and 3,000 MHz (or 3 GigaHertz) is considered to be in the UHF signal range. This range is less commonly known as the decimeter range. Frequencies immediately below 300 MHz are part of the VHF range. Radio frequencies above 3,000 MHz are categorized into the Super High Frequency Read More

Inclination is the angle between a satellite orbit and the equator. Inclination is measured as the angle at which the satellite crosses the equator while passing from the southern hemisphere to the northern hemisphere. A satellite travelling in a geostationary obit will have an inclination of zero. Inclination is between 0 and 90 degrees for satellites in non-retrograde orbits, and between 90 and 180 degrees for satellites in retrograde orbits. A satellite in a polar orbit will have an inclination of exactly 90 degree. A satellite with an inclination of Read More

A Bessel filter is a linear filter that is used in electronics and signal processing and has a flat group delay (also referred to as a maximally linear phase response). These filters are commonly used in audio crossover systems and preserve the wave shape of any filtered signals across the group delay in the passband. Who Invented the Bessel Filter? The Bessel filter is named after Friedrich Bessel, a German mathematician who lived from 1784 to 1846 and created the mathematical theory that the filters used today are based on. Read More

A Gauss meter is an instrument that measures magnetic field intensity. Electromagnetic fields can be found in numerous locations in the modern world. Electrical wiring in the home, power transmission lines, and household electronics such as televisions, computers, appliances, and clock radios create them. What is an Electromagnetic Field? An electromagnetic field is an invisible line of force created from alternating current flow through appliances or electrical lines. It surrounds all electronic devices. The U.S. Environmental Protection Agency (EPA), through the examination of existing studies, has found that over-exposure to Read More

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. In CB and ham radio circles, the SWR meter is used to help determine how much RF energy is being reflected back to the transmitter compared to how much is being sent out during operation. If the amount of reflected radiation is too Read More

XM Radio is a satellite radio service. Satellite radio is a technology that for the most part has been around for many years. For instance, many television studios have been using satellites to beam TV signals from far away locations to viewers for decades, however satellite radio has been in operation in America since 2001. Satellite radio is pretty easy to describe. The programs for satellite radio include music, talk shows, live sporting events and sport analysis shows. These shows are usually sent from one central location, where they are Read More

Coax connectors are essentially any connectors that are used to connect a coaxial cable to another cable or a device that requires a signal carried by the coaxial cable. They come in a variety of shapes and sizes and can be known by quite a few names. Among these, the most common alternative name for coax connectors are RF connectors. All coax connectors are designed for individual uses, and very few connectors share exactly the same function or design specifications. However, although there are many differences between coax connectors, there Read More