An operational amplifier is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op amp produces an output potential that is typically 100,000 times larger than the potential difference between its input terminals. The operational amplifier traces its origin and name to analog computers, where they were used to perform mathematical operations in linear, non-linear, and frequency-dependent circuits.
Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earphones or, colloquially, cans. Circumaural and supra-aural headphones use a band over the top of the head to hold the speakers in place. Another type, known as earbuds or earpieces consist of individual units that plug into the user's ear canal. A third type are bone conduction headphones, which typically wrap around the back of the head and rest in front of the ear canal, leaving the ear canal open. In the context of telecommunication, a headset is a combination of headphone and microphone.
PSK31 or "Phase Shift Keying, 31 Baud", also BPSK31 and QPSK31, is a popular computer-sound card-generated radioteletype mode, used primarily by amateur radio operators to conduct real-time keyboard-to-keyboard chat, most often using frequencies in the high frequency amateur radio bands (near-shortwave). PSK31 is distinguished from other digital modes in that it is specifically tuned to have a data rate close to typing speed, and has an extremely narrow bandwidth, allowing many conversations in the same bandwidth as a single voice channel. This narrow bandwidth makes better use of the RF energy in a very narrow space thus allowing relatively low-power equipment to communicate globally using the same skywave propagation used by shortwave radio stations.
Yaesu is a Japanese brand of commercial and amateur radio equipment, founded as Yaesu Musen Co., Ltd. in 1959 by a Japanese radio amateur Sako Hasegawa in Yaesu, Japan, a district of Tokyo.
Line level is the specified strength of an audio signal used to transmit analog audio between components such as CD and DVD players, television sets, audio amplifiers, and mixing consoles.
An S meter is an indicator often provided on communications receivers, such as amateur radio or shortwave broadcast receivers. The scale markings are derived from a system of reporting signal strength from S1 to S9 as part of the R-S-T system. The term S unit refers to the amount of signal strength required to move an S meter indication from one marking to the next.
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".
A test probe is a physical device used to connect electronic test equipment to a device under test (DUT). Test probes range from very simple, robust devices to complex probes that are sophisticated, expensive, and fragile. Specific types include test prods, oscilloscope probes and current probes. A test probe is often supplied as a test lead, which includes the probe, cable and terminating connector.
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.
Constant-voltage speaker systems refer to networks of loudspeakers which are connected to an audio amplifier using step-up and step-down transformers to simplify impedance calculations and to minimize power loss over the speaker cables. They are more appropriately called high-voltage audio distribution systems. The voltage is constant only in the sense that at full power, the voltage in the system does not depend on the number of speakers driven. Constant-voltage speaker systems are also commonly referred to as 25-, 70-, 70.7-, or 100-volt speaker systems; distributed speaker systems; or high-impedance speaker systems. In Canada and the US, they are most commonly referred to as 70-volt speakers. In Europe, the 100 V system is the most widespread, with amplifier and speaker products being simply labeled with 100 V.
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-817 is one of the smallest MF/HF/VHF/UHF multimode general-coverage amateur radio transceivers. The set is built by the Japanese Vertex Standard Corporation and is sold under the Yaesu brand. With internal battery pack, on board keyer, its all mode/all band capability and flexible antenna, the set is particularly well suited for portable use. The FT-817 is based on a similar circuit architecture as Yaesu's FT-857 and FT-897, so it is a compromise transceiver and incorporates its features to its low price.
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 FT-2900R is a VHF 2M FM mobile amateur radio transceiver. It is no longer in production and has been replaced by the FT-2980.
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.
The ICOM IC-705 is a multimode HF/VHF/UHF portable amateur radio transceiver. The radio has 5 watts of output when using its internal battery and 10 watts of output when using external power. With the rise in award programs such as Summits on the Air, and Parks on the Air this lightweight fully functional radio is a popular choice for people using them in the field. The IC-705 has support for a wide variety of commonly used amateur radio modes including ICOMs proprietary digital voice mode D-STAR. The IC-705 is also one of the first mainstream amateur radios to use SDR technology instead of the older superheterodyne design. Additionally the IC-705 has multiple extra features that are useful when operating in the field. Supporting the radio's D-STAR module is a GPS receiver to allow users to send their location though the D-STAR network as well as help locate nearby repeater systems. In addition to the GPS receiver the radio supports 2.4 GHz Wi-Fi which allows users to connect their computers or tablets to the IC-705 for running digital data modes such as PSK31, Winlink, and FT8. The radio has been praised for its size, easy to use menus, large easy to read screen and the quality of its build. Common criticisms of the radio include its lack of a built in antenna tuner and its price compared to other more powerful radios on the market.
The ICOM IC-7300 is a multimode 6 meter and HF base station amateur radio transceiver. The IC-7300 was announced to the public at the Japan Ham Fair in 2015. The radio has 100 watts output on CW, SSB, and FM modulations and 25 watts of output in AM. Although not the first SDR radio on the market The IC-7300 was the first mass-produced mainstream amateur radios to use SDR technology instead of the older superheterodyne transceiver design. Designed to replace the older IC-746PRO the IC-7300 is smaller and significantly lighter than its predecessor. Like many other radios of its class the IC-7300 has an internal antenna tuner and contains an internal audio card accessible over USB. This allows the radio to be used for popular digital modes such as PSK31, Winlink, and FT8. The radio has received praise for its easy to use menus, large readable screen, and excellent audio processing.
