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Yaesu (brand)
Yaesu, founded as in 1959 by a Japanese radio amateur Sako Hasegawa with call sign JA1MP in the Tokyo neighborhood of Yaesu, is a Japanese brand of commercial and amateur radio equipment. History The initial intent seemed to have been to develop and manufacture commercial and amateur radio transceivers for the Japanese market, but by 1964 there were sales agreements placed in Australia and Germany. In Europe, the equipment was sold under the Yaesu brand and the Sommerkamp brand. In 1963 the Swiss firm Sommerkamp imported Yaesu equipment and sold it using their own brand. Yaesu's line of equipment was first imported into the US by Spectronics, Inc. located in Signal Hill, California, in 1965. Yaesu became an important presence in the U.S. amateur radio market with the introduction and improvement of its very popular FT-101 line of equipment in the 1970s. In addition, transceivers were OEM'd to Henry Radio in Los Angeles. Spectronics was founded by William Turner, father of R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Privately Held Company
A privately held company (or simply a private company) is a company whose shares and related rights or obligations are not offered for public subscription or publicly negotiated in the respective listed markets, but rather the company's stock is offered, owned, traded, exchanged privately, or Over-the-counter (finance), over-the-counter. In the case of a closed corporation, there are a relatively small number of shareholders or company members. Related terms are closely-held corporation, unquoted company, and unlisted company. Though less visible than their public company, publicly traded counterparts, private companies have major importance in the world's economy. In 2008, the 441 list of largest private non-governmental companies by revenue, largest private companies in the United States accounted for ($1.8 trillion) in revenues and employed 6.2 million people, according to ''Forbes''. In 2005, using a substantially smaller pool size (22.7%) for comparison, the 339 companies on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARRL
The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization, and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska of Hartford, Connecticut. The ARRL represents the interests of amateur radio operators before federal regulatory bodies, provides technical advice and assistance to amateur radio enthusiasts, supports a number of educational programs and sponsors emergency communications service throughout the country. The ARRL has approximately 161,000 members. In addition to members in the US, the organization claims over 7,000 members in other countries. The ARRL publishes many books and a monthly membership journal called ''QST''. The ARRL is the primary representative organization of amateur radio operators to the US government. It performs this function by lobbying the US Congress and the Federal Communications Commission. The ARRL is also the internati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude Modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its phase, as in phase modulation. AM was the earliest modulation method used for transmitting audio in radio broadcasting. It was developed during the first quarter of the 20th century beginning with Roberto Landell de Moura and Reginald Fessenden's radiotelephone experiments in 1900. This original form of AM is sometimes called double-sideband amplitude modulation (DSBAM), because the standard method produces sidebands on either side of the carrier frequency. Single-sideband modulation uses bandpass filters to eliminate one of the sidebands and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Receiver (radio)
In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. The antenna intercepts radio waves (electromagnetic waves of radio frequency) and converts them to tiny alternating currents which are applied to the receiver, and the receiver extracts the desired information. The receiver uses electronic filters to separate the desired radio frequency signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation. Radio receivers are essential components of all systems that use radio. The information produced by the receiver may be in the form of sound, video (television), or digital data. A radio receiver may be a separate piece of electronic equipment, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Receiver
A communications receiver is a type of radio receiver used as a component of a radio communication link. This is in contrast to a ''broadcast receiver'' which is used to receive radio broadcasts. A communication receiver receives parts of the radio spectrum not used for broadcasting, that includes amateur, military, aircraft, marine, and other bands. They are often used with a radio transmitter as part of a two-way radio link for shortwave radio or amateur radio communication, although they are also used for shortwave listening. Features Commercial communications receivers are characterized by high stability and reliability of performance, and are generally adapted for remote control and monitoring. For marketing purposes, many hobby-type receivers are advertised as "communications receivers" although none are suited for heavy-duty, reliable 24-hour use as the primary form of communication for an isolated station. Typically, a communications receiver is of the superheterody ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Frequency Allocations
Amateur radio frequency allocation is done by national telecommunication authorities. Globally, the International Telecommunication Union (ITU) oversees how much radio spectrum is set aside for amateur radio transmissions. Individual amateur stations are free to use any frequency within authorized frequency ranges; authorized bands may vary by the class of the station license. Radio amateurs use a variety of transmission modes, including Morse code, radioteletype, data, and voice. Specific frequency allocations vary from country to country and between ITU regions as specified in the current ITU HF frequency allocations for amateur radio. The list of frequency ranges is called a ''band allocation'', which may be set by international agreements, and national regulations. The modes and types of allocations within each frequency band is called a bandplan; it may be determined by regulation, but most typically is set by agreements between amateur radio operators. National authorities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Frequency
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters). Frequencies immediately below HF are denoted medium frequency (MF), while the next band of higher frequencies is known as the very high frequency (VHF) band. The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or " skywave" propagation – these frequencies are suitable for long-distance communication across intercontinental distances and for mountainous terrains which prevent line-of-sight communications. The band is used by international shortwave broadcasting stations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yaesu FRG-7700
Yaesu, founded as in 1959 by a Japanese radio amateur Sako Hasegawa with call sign JA1MP in the Tokyo neighborhood of Yaesu, is a Japanese brand of commercial and amateur radio equipment. History The initial intent seemed to have been to develop and manufacture commercial and amateur radio transceivers for the Japanese market, but by 1964 there were sales agreements placed in Australia and Germany. In Europe, the equipment was sold under the Yaesu brand and the Sommerkamp brand. In 1963 the Swiss firm Sommerkamp imported Yaesu equipment and sold it using their own brand. Yaesu's line of equipment was first imported into the US by Spectronics, Inc. located in Signal Hill, California, in 1965. Yaesu became an important presence in the U.S. amateur radio market with the introduction and improvement of its very popular FT-101 line of equipment in the 1970s. In addition, transceivers were OEM'd to Henry Radio in Los Angeles. Spectronics was founded by William Turner, father o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yaesu FRG-7000
is a district in Chūō, Tokyo, Japan, located north of Ginza, west of Nihonbashi and Kyōbashi, and adjacent to the east side of Tokyo Station. The Yaesu exit of this station, which faces Nihonbashi, is recent and primarily provides access to the Shinkansen platforms. History The area was named after the 17th century Dutch adventurer Jan Joosten van Lodensteijn, or simply Jan Joosten. For his services to Tokugawa Ieyasu he was granted a house in Edo (now Tokyo) in an area that came to be called "Yayosu Quay" after him — his name was pronounced ''yan yōsuten'' in Japanese (short version: Yayōsu (耶楊子)) — the Yaesu side of Tokyo Station is also named for him. Yaesu Avenue has a monument dedicated to Jan Joosten and his life after his arrival in Japan on ''De Liefde'' with his shipmate William Adams. Ukiyo-e artist Andō Hiroshige was born in the Yayosu barracks in the Yaesu area in 1797. Places in Yaesu *Tokyo Station and highway bus platforms * Yaesu underg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadraphonic
Quadraphonic (or quadrophonic and sometimes quadrasonic) sound – equivalent to what is now called 4.0 surround sound – uses four audio channels in which speakers are positioned at the four corners of a listening space. The system allows for the reproduction of sound signals that are (wholly or in part) independent of one another. Four channel quadraphonic surround sound can be used to recreate the highly realistic effect of a three-dimensional live concert hall experience in the home. It can also be used to enhance the listener experience beyond the directional limitations of ordinary two channel stereo sound. Quadraphonic audio was the earliest consumer product in surround sound. Since it was introduced to the public in the early 1970s many thousands of quadraphonic recordings have been made. Quadraphonic sound was a commercial failure when first introduced due to a variety of technical issues and format incompatibilities. Four channel audio formats can be more expensive to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Mobile Radio
Digital mobile radio (DMR) is a specification for commercial products so they can interoperate. It is defined by a standard created by the European Telecommunications Standards Institute (ETSI), and is designed to be low-cost and easy to use. DMR, along with P25 phase II and NXDN are the main competitor technologies in achieving 6.25 kHz equivalent bandwidth using the proprietary AMBE+2 vocoder. DMR and P25 II both use two-slot TDMA in a 12.5 kHz channel, while NXDN uses discrete 6.25 kHz channels using frequency division and TETRA uses a four-slot TDMA in a 25 kHz channel. DMR was designed with three tiers. DMR tiers I and II (conventional) were first published in 2005, and DMR III (Trunked version) was published in 2012, with manufacturers producing products within a few years of each publication. The primary goal of the standard is to specify a digital system with low complexity, low cost and interoperability across brands, so radio communications purchasers a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D-STAR
D-STAR (Digital Smart Technologies for Amateur Radio) is a digital voice and data protocol specification for amateur radio. The system was developed in the late 1990s by the Japan Amateur Radio League and uses minimum-shift keying in its packet-based standard. There are other digital modes that have been adapted for use by amateurs, but D-STAR was the first that was designed specifically for amateur radio. Several advantages of using digital voice modes are that it uses less bandwidth than older analog voice modes such as amplitude modulation and frequency modulation. The quality of the data received is also better than an analog signal at the same signal strength, as long as the signal is above a minimum threshold and as long as there is no multipath propagation. D-STAR compatible radios are available for HF, VHF, UHF, and microwave amateur radio bands. In addition to the over-the-air protocol, D-STAR also provides specifications for network connectivity, enabling D-STAR radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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