Antenna fundamentals

The ideas that apply to every antenna.

How antennas workTurning current into radio waves and back again.Gain and directivitydBi, dBd and where the energy goes.Radiation patternsReading azimuth and elevation plots, beamwidth and front-to-back.Antenna impedance and radiation resistanceWhat the feed line sees at the feed point.Bandwidth and efficiencyHow wide an antenna works and how much power is actually radiated.Ground effects and heightHow earth and height shape the pattern.Near field and far fieldWhy distance from the antenna changes the physics.Antenna modelingUsing NEC-based software to predict performance.