reversed-frequency operation
71Shortwave radio — Shortwave can also refer to a shortwave trough meteorology. A solid state, analog shortwave receiver Shortwave radio refers to the upper MF (medium frequency) and all of the HF (high frequency) portion of the radio spectrum, between… …
72Photonic metamaterial — Electromagnetism Electricity · …
73Shortwave — radio operates between the frequencies of 3,000 kHz (3.000 MHz) and 30,000 kHz (30.000 MHz) [ Tomislav Stimac, [http://www.vlf.it/frequency/bands.html Definition of frequency bands (VLF, ELF... etc.)] . IK1QFK Home Page (vlf.it).] and came to be… …
74Italy — /it l ee/, n. a republic in S Europe, comprising a peninsula S of the Alps, and Sicily, Sardinia, Elba, and other smaller islands: a kingdom 1870 1946. 57,534,088; 116,294 sq. mi. (301,200 sq. km). Cap.: Rome. Italian, Italia. * * * Italy… …
75Military Affairs — ▪ 2009 Introduction Russia and Georgia fought a short, intense war in 2008, fueling global fears of a new Cold War. On August 7 Georgia launched an aerial bombardment and ground attacks against its breakaway province of South Ossetia.… …
76Physical Sciences — ▪ 2009 Introduction Scientists discovered a new family of superconducting materials and obtained unique images of individual hydrogen atoms and of a multiple exoplanet system. Europe completed the Large Hadron Collider, and China and India took… …
77Resistor — A typical axial lead resistor Type Passive Working principle Electrical resistance Invented Ge …
78Pendulum — This article is about pendulums. For other uses, see Pendulum (disambiguation). Simple gravity pendulum model assumes no friction or air resistance …
79AC motor — An AC motor is an electric motor that is driven by an alternating current. It consists of two basic parts, an outside stationary stator having coils supplied with AC current to produce a rotating magnetic field, and an inside rotor attached to… …
80How television works — Analog televisionUntil the advent of digital television and flat panel displays in the 1990s, all television was based on the transmission and reception of analog signals, displayed on a cathode ray tube. Although a number of different broadcast… …
