Free RF animations and java applets, Antenna animations

Radio frequency (RF) refers to the range of electromagnetic frequencies used for wireless communication, broadly from a few kilohertz up to hundreds of gigahertz. An electromagnetic wave consists of electric and magnetic fields oscillating at right angles to each other and to the direction of travel. Such a wave is produced whenever electric charge accelerates; an alternating current in a conductor causes charges to oscillate, and the changing fields they create detach from the conductor and propagate outward at the speed of light.

The behaviour of an RF signal depends strongly on its frequency, since wavelength and frequency are inversely related. Lower frequencies have long wavelengths that can follow the curve of the Earth or bounce off the ionosphere, supporting long-distance reach. Higher frequencies travel in straighter, more line-of-sight paths but allow smaller antennas and wider bandwidths. These differences shape how bands are allocated for broadcasting, mobile telephony, radar, satellite links and many other services.

Because the fields of a radio wave are invisible and vary in both space and time, animations and applets are particularly helpful for studying them. A simulation can show electric field lines whipping off an oscillating charge, the way crossed electric and magnetic fields advance together, and how the radiated pattern changes with the source. Visualising wave propagation, polarisation and the link between current in an antenna and the field it launches helps connect the underlying mathematics of Maxwell's equations to observable behaviour.

Frequently asked questions

How are radio waves generated?: Accelerating electric charge radiates electromagnetic energy. An alternating current makes charges in an antenna oscillate, and the changing fields propagate away as a radio wave.
What is an electromagnetic wave made of?: It is a pair of oscillating electric and magnetic fields, perpendicular to each other and to the direction of travel, moving together through space at the speed of light.
Why does frequency affect how far a signal travels?: Lower frequencies have long wavelengths that can bend around terrain or reflect off the ionosphere, while higher frequencies travel mostly in straight, line-of-sight paths.

Radio frequency animations and java applets

AM Detector

Animations of the 2D propagation of electromagnetic waves in the presence of different distributions of refractive index This page contains animations of numerical solutions to Maxwell's equations in a 2D domain (using the finite-difference time-domain method with a staggered "Yee lattice"). A wave is excited at the bottom of the domain and propagates upwards

Communication engineering applets to understanding some of the principles of telecommunication engineering

Electromagnetic field animations

Electromagnetic theory antennas, polarization, standing wave, reflection and transmission, radiation from the source, diffraction by a half-infinite ground plane, microwave circuits, ..., a tip

Electromagnetic oscillating circuit this simulation deals with an electromagnetic oscillating circuit, consisting of a capacitor and an inductor

How Radio Communication Works How Radio Communication Works

Ionization Factors Because there are fewer hours of daylight during autumn and winter, less radiation reaches the D and E layers. Lower frequencies pass easily through these weakly ionized The process in which electrons are stripped from atoms and produce electrically charged particles. layers. Therefore, signals arriving at the F layer The ionospheric layer that is most responsible for long-haul HF radio communications. are stronger and are reflected over greater distances

IONOSHERE

Mobile Computing Applets CDMA, IrDA, Bluetooth-Scatternet, DSDV Routing, DSR Routing, OLSR Routing, Link-Reversal

Morse

Physics, electromagnetism and quantum mechanics details the findings of Larry Spring in areas such as physics, electromagnetism and quantum mechanics

Phase Locked Loop (PLL) Phase locked loop (PLL) is used for synchronous demodulation of AM signals with suppressed carrier or little carrier

Propagation loss models used in cellular system planning these applets plot the graphs of path loss (dB) against distance (km) on a grid

Sky waves Sky waves Radio signals that are bent back to Earth by the ionosphere. make beyond line-of-sight communications possible. At certain frequencies, radio waves are refracted, or bent, returning to Earth hundreds or thousands of miles away. Depending on frequency The number of cycles a radio wave completes in a given period of time., time of day, and atmospheric conditions, a signal can bounce several times before reaching a receiver

T-network tuner simulator a simulator for the popular, series capacitor, parallel inductor T-network tuners, SWR

Time domain vs. frequency domain the three-dimensional plot of frequency, amplitude and time that shows the relationship between the time and frequency domains. It does so by looking at the fundamental of a sine wave -- and up to three harmonics -- as they are formed by rotating vectors

Tuning a radio receiver this tutorial demonstrates how variable capacitors are used with inductor coils in tuning circuits of radios, television sets, and a number of other devices that must isolate electromagnetic radiation of selected frequencies

Satellites and GPS systems

related topic: Satellite Motion and Tracking

Cellphone

Earth orbit plot earth orbit plot, swf file

GPS and GLONASS Satellite Networks GPS and GLONASS Satellite Networks - ESSP - European Satellite

GPS and GLONASS simulation

GPS and the use of satellites GPS and the use of satellites, swf file

GPS Animation Global Positioning System (GPS)

GPS Global Positioning System GPS Global Positioning System

GPS: How GPS works How GPS works animation

GPS: How GPS works How GPS works, satellites

GPS Satellite Display In Google Earth

Orbits GPS Orbits GPS, swf file

REAL TIME SATELLITE TRACKING

Simple satellite tracker

Space Communication

Use sun or moon to choose the best place for your satellite antenna

Sun-Satellite Interference Geosynchronous satellites are used for many telecommunication and broadcast purposes. Such satellites appear to be stationary as viewed from the ground, and are able to provide coverage over large areas

War with Iraq Guided weapons swf file

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