A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carrier frequency. It was long believed to have been invented by US engineer Edwin Armstrong, but after some controversy the earliest patent for the invention is now credited to French radio engineer and radio manufacturer Lucien Lévy. Virtually all modern radio receivers use the superheterodyne principle; except those software-defined radios using direct sampling.
The Tilted Terminated Folded Dipole or Balanced Termination, Folded Dipole (BTFD) - also known as W3HH antenna - is a general-purpose shortwave antenna developed in the late 1940s by the United States Navy. It performs reasonably well over a broad frequency range, without marked dead spots in terms of either frequency, direction, or angle of radiation above the horizon.
Yaesu, founded as Yaesu Musen Co., Ltd. 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.
A tuner is a subsystem that receives radio frequency (RF) transmissions, such as FM broadcasting, and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually because a lower frequency is used on the output. Broadcast FM/AM transmissions usually feed this intermediate frequency (IF) directly into a demodulator that converts the radio signal into audio-frequency signals that can be fed into an amplifier to drive a loudspeaker.
A braid-breaker is a filter that prevents television interference (TVI). In many cases, TVI is caused by a high field strength of a nearby high frequency (HF) transmitter, the aerial down lead plugged into the back of the TV acts as a longwire antenna or as a simple vertical element. The radio frequency (RF) current flowing through the tuner of the TV tends to generate harmonics which then spoil the viewing.
A radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. Radio waves are electromagnetic waves with frequencies between about 30 Hz and 300 GHz. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. Transmitters are necessary parts of all systems that use radio: radio and television broadcasting, cell phones, wireless networks, radar, two way radios like walkie talkies, radio navigation systems like GPS, remote entry systems, among numerous other uses.
Yaesu FT-101 is a model line of modular amateur radio transceivers, built by the Yaesu Corporation in Japan during the 1970s and 1980s. FT-101 is a set that combines a solid state transmitter, receiver and a tube final amplifier. Its solid state features offer high-performance, low-current characteristics and its tube amplifier provides an almost mismatch-resistant transmitter and tuner stage. FT-101s were made with plug-in circuit boards that could be sent to the dealer or factory for replacement or repair. Until then, modular design was unprecedented in the amateur community. This also explains the fact why so many FT-101s are still in use today. The rig was sold worldwide as Yaesu FT-101 and in Europe as Yaesu FT-101 and as Sommerkamp FT-277. Because of its reliability it earned its nickname "the workhorse".
An EMC problem occurs when one piece of electronic equipment or an electromagnetic system is adversely affected by the operation of another. One example might be breakthrough by the high field strengths produced by a nearby radio transmitter. EMC problems are not always due to defects in the transmitter, and so do not necessarily require improvements in the radio transmitter design, such as reducing its radiated harmonics. It may be that the immunity of the affected equipment is poor due to inadequate shielding, or filtering of sensitive inputs. EMC problems can have a range of effects on equipment, and there are ways to mitigate or eliminate them in practice. Effective EMC mitigation techniques may differ by the type of equipment that malfunctions, and by the nature of the strong radio frequency field.
Clansman is the name of a combat net radio system (CNR) used by the British Army from 1976 to 2010.
Explorer 49 was a NASA 328 kg (723 lb) satellite launched on 10 June 1973, for long wave radio astronomy research. It had four 230 m (750 ft) X-shaped antenna elements, which made it one of the largest spacecraft ever built.
The AN/PRC-150(C) Falcon II Manpack Radio, is a tactical HF-SSB/ VHF-FM manpack radio manufactured by Harris Corporation. It holds an NSA certification for Type 1 encryption.
A preselector is a name for an electronic device that connects between a radio antenna and a radio receiver. The preselector is a band-pass filter that blocks troublesome out-of-tune frequencies from passing through from the antenna into the radio receiver that otherwise would be directly connected to the antenna.
The SCR-300 was a portable radio transceiver used by US Signal Corps in World War II. This backpack-mounted unit was the first radio to be nicknamed a "walkie talkie".
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The Yaesu FT-ONE is an all-mode solid state general coverage HF amateur radio (HAM) transceiver. The use of FM required an optional FM board to be installed. The unit was designed for fixed, portable or mobile operation, although the size and weight (17 kg) made it more suitable for fixed use. The FT-ONE was built by the Japanese Yaesu-Musen Corporation from 1982 to 1986. At its release, the FT-ONE was launched as the successor to the FT-902 and as the new Yaesu top-of-the-line transceiver. The FT-ONE was not only Yaesu's first fully synthesized, computer-controlled amateur band transceiver but it was also the first transceiver with a general coverage receiver. The FT-ONE was sold in the U.S., Asian and European markets. It was released in 1982 with a list price of $2800.00 US.
The Yaesu FT-77 is a transceiver to be used in the 3,5 – 29,9 MHz shortwave radio amateur segment. This means the coverage of the 80-40-30-20-15-17-12 and 10 meter HF bands.
The Yaesu VX series is a line of two sequences of compact amateur radio handheld transceivers produced by Yaesu. There is a line of ultra-compact lower-power dual-band transceivers that started with the VX-1R and was later updated with the VX-2R and VX-3R. There is also a line of 5W tri-band transceivers that started with the VX-5R and was later updated with the VX-6R, VX-7R and VX-8R.
The Yaesu FT-891 is a HF + 6 meters all mode mobile amateur radio transceiver. The FT-891 was first announced to the public by Yaesu at the 2016 Dayton Hamvention. The radio has 100 watts output on CW, SSB, and FM modulations and 25 watts of output in AM. As a mobile transceiver the FT-891 is well suited for mobile installation in vehicles, and weighing less than 5 pounds it is often used for field activations such as Summits on the Air, and Parks on the Air. The radio has been praised for its noise reduction and sensitive receiver. Common criticisms of the radio include it's many menus that are difficult to navigate with its small screen, the lack of VHF/UHF capabilities, and lack of an internal antenna tuner. Although the radio lacks an internal sound card it still has input and output jacks for audio and be controlled over a USB cable allowing the radio to use digital modes such as WinLink, PSK31 and FT8.
