Change a parameter — see what happens
Wi-Fi you can see
Three adjustable workbenches: an electromagnetic wave, router placement and a signal meeting an obstacle. Move, rotate and explore your idea.
Wave and polarization
E and B oscillate across propagation direction k. Change the wave direction separately from the viewpoint: rotating the viewer does not change physical polarization.
Drag with a mouse or use the sliders. Enable touch rotation to drag with a finger; keyboard arrows also rotate the view.
Cyan is electric field E, green is magnetic field B. They use separate normalized display scales: in vacuum |B| = |E| / c. The spatial helix shows vectors at different positions; matter does not travel in a helix.
Placement and power
Drag the AP and client on the plan or set their coordinates. Raise only AP transmit power: its signal gets stronger, while the client’s reply remains unchanged.
12 × 7 m plan. Color is illustrative downlink margin against the client threshold: green above, brown near, burgundy below. Light rings represent schematic wavefronts, not a coverage boundary.
A teaching model of the direct path: free-space loss at 1 m, exponent n and one wall where the ray crosses it. Rooms, reflections, antennas and neighboring networks need measurements; this is not a site survey. The opening adds no wall loss.
Gain is the same for transmit and receive in the chosen direction
Gain is the same for transmit and receive in the chosen direction. Receive thresholds are independent; they do not select MCS or promise a data rate.
A simple dipole has a doughnut shaped 3D pattern, weakest along its antenna axis. Real routers use multiple antennas and other patterns: follow the manufacturer’s mounting instructions. Antenna gain redistributes energy; it does not create it.
PL = FSPL(1 m) + 10 n log₁₀(max(1, d)) + Lwall
Pr = Pt + Gt + Gr − PL
Obstacles and materials
Choose an illustrative scenario and change reflected and absorbed power fractions. The remaining energy passes through. Change incidence: the reflected ray stays symmetric about the normal.
Ray width scales with √power fraction. Transmission is schematic: refraction, phase changes, scattering and diffraction are not calculated.
Models and primary sources
Plane wave physics and simple power budgets. Material scenarios are editable illustrations; real site performance requires a survey and measurements.