Trickle charging, also called float charging, is the replacement of charge lost through self-discharge. Trickle chargers work at a lower rate than quick chargers, and are used to keep a battery at full charge, not to charge it from empty. Some battery chargers use electronics to control both quick and trickle charge modes, allowing them to change modes once a battery is fully charged. Self-Discharge All batteries lose some of their charge over time without any connection between the contacts. The rate of self-discharge depends on the type of battery Read More

Quadrature Amplitude Modulation (QAM) is a complicated name for a simple technique. In the simplest of terms, Quadrature amplitude modulation is the combination of amplitude modulation and phase shift keying. More technically, quadrature amplitude modulation is a system of modulation in which data is transferred by modulating the amplitude of two separate carrier waves, mostly sinusoidal, which are out of phase by 90 degrees (sine and cosine). Due to their phase difference, they are called quadrature carriers. Unmodulated signals exhibit only two positions enabling a transfer of either a 0 Read More

MCX is a type of connector developed in the 1980’s and used in the microwave transmission range. It carries frequencies of up to 6 GHz and is the second smallest of the subminiature connector families. At approximately 30% smaller than Subminiature B connectors (measuring in at 0.140 inches on the outer diameter of the plug), MCX is designed to completely minimize any leakage at its joints. The MCX connector is used with a standard coaxial cable and features a snap-on interface in which the connectors are simply pressed together to Read More

The term wire gauge refers to a measurement of what the diameter of a wire is. This measure can then be used to determine what the electrical resistance, weight per unit of length, and the amount of current that can safely be carried by the wire. There are two internationally accepted measures for wire gauge, the Metric Wire Gauge (MWG) and American Wire Gauge (AWG) standards. American Wire Gauge (AWG) The standardized gauge system used for wire measurement in the United States and Canada is the AWG, or American Wire Read More

SSB stands for Single Side Band. In SSB, the carrier and one of the side bands are eliminated before transmission. This enables the power amplifier to focus all transmitter energy on the single remaining sideband. SSB allows greater range with less power consumption. SSB also enables more efficient utilization of the radio frequency spectrum. The SSB receiver reinserts the proper carrier after reception and before modulation.

The Frequency-Hopping Spread Spectrum (FHSS) is a means of transmitting radio signals by shifting a carrier across a number of channels with a pseudorandom sequence that the sending and receiving station knows beforehand. The method is used as a multiple access process in the FH-CDMA (Frequency Hopping Code Division Multiple Access) transmission scheme. What Are the Advantages of Spread-Spectrum Transmission? The frequency hopping spread spectrum over a fixed-frequency transmission method has 3 primary advantages: #1 – The method is very resistant to narrow band interference since the spread signal causes Read More

Variac is the trademark name of a variable autotransformer. A variable autotransformer is a single-coil transformer in which two portions of the same coil are used as the primary and the secondary. Variable autotransformers are used for the same purposes as regular transformers, but handle lower voltages. They also differ from regular autotransformers in that they are equipped with automatic switchgear in order to automatically step a voltage up or down, depending on preset conditions. How Variacs Work Variable autotransformers consist of a regular autotransformer that has been scratched in Read More

The broad definition of a transducer is a device that changes energy from one type into another. However, most transducers change between electricity and another energy type. Transducers also have other names depending on their usage such as probe, detector, pickup, sensor, gauge, and electrode. Chemical Transducers Acidity and alkalinity are measured using a pH meter and an ion-sensitive electrode. The electrode is a complex device consisting of many parts but is essentially a galvanic cell. The voltage produced by the electrode depends on the concentration of hydrogen ions in Read More

C Band is the original frequency allocation for communications satellites. C-Band uses 3.7-4.2GHz for downlink and 5.925-6.425Ghz for uplink. The lower frequencies that C Band uses perform better under adverse weather conditions than the Ku band or Ka band frequencies. C Band Variants Slight C Band frequency variations are approved for use in various parts of the world. Band TX Frequency RX Frequency Extended C Band 5.850 – 6.425 GHz 3.625 – 4.200 GHz Super Extended C-Band 5.850 – 6.725 GHz 3.400 – 4.200 GHz INSAT C-Band 6.725 – 7.025 Read More

A weather satellite is a satellite which is used by meteorologists to gather information about the weather. Weather satellites give meteorologists a view of weather patterns over a very large area. This enables meteorologists to track large weather patterns and make more accurate predictions of future weather behavior. In addition to visual monitoring, weather satellites may also use thermal imaging, X-ray sensors, high-energy proton detectors, alpha detectors, and energetic particle sensors. Weather satellites travel in either geostationary or polar orbits. Weather satellites in geostationary orbits provide views of the same Read More