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Diagram of leaky feeder cable. A leaky feeder is a communications system used in underground mines and inside tunnels. [1] Manufacturers and cabling professionals use the term "radiating cable" [2] [3] [better source needed] [4] as this implies that the cable is designed to radiate: something that a typical coaxial cable is generally not intended to do.
A grid leak resistor and capacitor unit from 1926. The 2 megohm cartridge resistor is replaceable so the user can try different values. The parallel capacitor is built into the holder. A grid leak detector is an electronic circuit that demodulates an amplitude modulated alternating current and amplifies the recovered modulating voltage. The ...
The cable has a characteristic impedance of 75 ohms, and a capacitance of around 20pF/ft (60pF/m). [1] The 75 ohm impedance matches a dipole antenna in free space. RG (for radio guide ) was originally a unit indicator for bulk radio frequency (RF) cable in the U.S. military's Joint Electronics Type Designation System .
Cross-section through a coaxial cable showing shielding and other layers. One example is a shielded cable, which has electromagnetic shielding in the form of a wire mesh surrounding an inner core conductor. The shielding impedes the escape of any signal from the core conductor, and also prevents signals from being added to the core conductor.
Plate detector circuit with cathode bias. Cathode bias RC time constant three times period of lowest carrier frequency. C L is typically around 250 pF.. In electronics, a plate detector (anode bend detector, grid bias detector) is a vacuum tube circuit in which an amplifying tube having a control grid is operated in a non-linear region of its grid voltage versus plate current transfer ...
A residual-current device (RCD), residual-current circuit breaker (RCCB) or ground fault circuit interrupter (GFCI) [a] is an electrical safety device, more specifically a form of Earth-leakage circuit breaker, that interrupts an electrical circuit when the current passing through line and neutral conductors of a circuit is not equal (the term residual relating to the imbalance), therefore ...
independent of frequency (λc is the cutoff wavelength). On the contrary, when the guiding structure is partly filled with dielectric, the transverse wavenumber kt is a function of frequency, so that Δθ changes as the beam is frequency scanned. On the other hand, with respect to frequency sensitivity, i.e., how quickly the beam angle scans as ...
Tempest for Eliza is a program that uses a computer monitor to send out AM radio signals, making it possible to hear computer-generated music in a radio. Video eavesdropping demo at CeBIT 2006 by a Cambridge University security researcher; eckbox – unsuccessful or abandoned attempt in spring 2004 to build an open-source Van Eck phreaking ...