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  2. Line-of-sight propagation - Wikipedia

    en.wikipedia.org/wiki/Line-of-sight_propagation

    Line of sight (LoS) propagation from an antenna. Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation which means waves can only travel in a direct visual path from the source to the receiver without obstacles. [1] Electromagnetic transmission includes light emissions traveling in a straight line.

  3. Line of sight - Wikipedia

    en.wikipedia.org/wiki/Line_of_sight

    Line-of-sight propagation, electro-magnetic waves travelling in a straight line Non-line-of-sight propagation; Line-of-sight fire, shooting directly at a visible target on a relatively flat trajectory; Line-of-sight velocity, an object's speed straight towards or away from an observer; Line-of-sight double star, one in which two stars are only ...

  4. Johnson's criteria - Wikipedia

    en.wikipedia.org/wiki/Johnson's_criteria

    The minimum required resolution according to Johnson's criteria are expressed in terms of line pairs of image resolution across a target, in terms of several tasks: [3] Detection, an object is present (1.0 +/− 0.25 line pairs) Orientation, symmetrical, asymmetric, horizontal, or vertical (1.4 +/− 0.35 line pairs)

  5. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    On the surface of the Earth, line of sight propagation is limited by the visual horizon to about 64 km (40 mi). This is the method used by cell phones , FM , television broadcasting and radar . By using dish antennas to transmit beams of microwaves, point-to-point microwave relay links transmit telephone and television signals over long ...

  6. Propagation graph - Wikipedia

    en.wikipedia.org/wiki/Propagation_graph

    A propagation graph is a simple directed graph = (,) with vertex set and edge set .. The vertices models objects in the propagation scenario. The vertex set is split into three disjoint sets as = where is the set of transmitters, is the set of receivers and is the set of objects named "scatterers".

  7. List of iPhone models - Wikipedia

    en.wikipedia.org/wiki/List_of_iPhone_models

    The iPhone, developed by Apple Inc., is a line of smartphones that combine a mobile phone, digital camera, personal computer, and music player into one device. Introduced by then-CEO Steve Jobs on January 9, 2007, the iPhone revolutionized the mobile phone industry with its multi-touch interface and lack of physical keyboard.

  8. AOL Mail

    mail.aol.com

    Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!

  9. Egli model - Wikipedia

    en.wikipedia.org/wiki/Egli_Model

    The Egli model is a terrain model for radio frequency propagation.This model, which was first introduced by John Egli in his 1957 paper, [1] was derived from real-world data on UHF and VHF television transmissions in several large cities.