In order to deter theft, the majority of major automobile manufacturers implement a car radio security code. When the car stereo is removed from a vehicle, the device will not be usable until the unlock or security code is entered by the car owner or authorized repair facility. Unfortunately, some models of cars and trucks …
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 …
dBm is the standard unit of measure for levels of power based on a one milliwatt (mW) reference signal. The dBm measurement is very similar to dB (decibel); however, dB is a relative measure of the power of an input signal while dBm is always an absolute value based on a single milliwatt. If there …
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. Pulse position modulation exclusively transfers digital signals and cannot be used …
Modulation is the process of varying some characteristic of a periodic wave with external signals. Modulation is utilized to send an information bearing signal over long distances. Radio communication superimposes this information bearing signal onto a carrier signal. These high frequency carrier signals can be transmitted over the air easily and are capable of traveling …
MURS, or the Multi-Use Radio Service, is a public radio service created by the FCC in the Fall of 2000 that can be accessed by any individual for personal or business-related purpose. MURS was created for the general public to use without acquiring a license to broadcast, but requires that users remain within the frequencies …
Amplitude modulation is a type of modulation where the carrier signal’s amplitude is varied in accordance with the information bearing signal. The amplitude modulated signal’s envelope or boundary embeds the information bearing signal. The total power of the transmitted signal varies with the modulating signal, whereas the carrier power remains constant. A nonlinear device combines …
The military alphabet, or more properly the phonetic alphabet, exists in innumerable variants. If any military alphabet can be viewed as the most correct, it is the current NATO standard military alphabet. However, even with the NATO standard military alphabet, various member nations use numerous spelling variations. This version of the military alphabet is also …
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 …
Radio-Frequency Identifier (RFID) technology has become really popular because of the various advantages it comes with. However, such as passports, national identity cards, credit cards etc have become a serious security concern. Two electrical engineering students (Ilan Kirschenbaum and Avishai Wool) from Tel Aviv University wrote a paper titled "How to Build a Low-Cost, …