amateur band amplitude antinode band channel citizens band crest de Broglie wave diffraction electromagnetic radiation electromagnetic wave fluctuation frequency frequency spectrum guided wave harmonic motion in phase interference libration light longitudinal wave mechanical wave node nutation oscillation out of phase pendulation period periodic wave periodicity police band radio channel radio wave ray reinforcement resonance resonance frequency seismic wave shock wave shortwave band sound wave standard band surface wave tidal wave transverse wave trough vacillation vibrancy vibratility vibration wave wave equation wave motion wave number wavelength wavering