high-frequency buzzer
1Crystal radio — Crystal set redirects here. For the Australian rock band, see The Crystal Set. A modern reproduction of an antique crystal set. It is tuned to different stations by moving the sliding contact (right) up and down the tuning coil (red). The device… …
2Cat's-whisker detector — Galena cat s whisker detector Precision cat s whisker d …
3Invention of radio — Great Radio Controversy redirects here. For the album by the band Tesla, see The Great Radio Controversy. Contents 1 Physics of wireless signalling 2 Theory of electromagnetism …
4Inverter (electrical) — An inverter is an electrical device that converts direct current (DC) to alternating current (AC)[1]; the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits. Solid… …
5Numbers station — Fictional example of a numbers station. Numbers stations (or number stations) are shortwave radio stations of uncertain origin. In the 1950s, Time magazine reported that the numbers stations first appeared shortly after World War II and were… …
6Brevity code — Contents 1 American/NATO codes 1.1 A 1.2 B 1.3 C …
7Morse code — Chart of the Morse code letters and numerals Morse code is a method of transmitting textual information as a series of on off tones, lights, or clicks that can …
8National Emergency Alarm Repeater — The N.E.A.R. Warning Device. The National Emergency Alarm Repeater (NEAR) was a civilian emergency warning device in the United States. It was a 2 3 (5 7.5cm) square box designed to plug into a standard 110 volt power outlet to receive a special… …
9Mobile Telephone Service — The Mobile Telephone Service (MTS) is a pre cellular VHF radio system that links to the Public Switched Telephone Network (PSTN). MTS was the radiotelephone equivalent of land dial phone service. As of 2005[update], only rural and wilderness… …
10horn — Synonyms and related words: Klaxon, Mayday, SOS, acoustical network, aerophone, air raid alarm, alarm, alarm bell, alarm clock, alarm signal, alarum, alert, all clear, alpenhorn, alphorn, althorn, alto horn, ballad horn, baritone, bass horn,… …
