There are three main modes of radio wave propagation: ground-wave propagation for frequencies below 2 MHz, sky-wave propagation between 2-30 MHz, and line-of-sight propagation for frequencies above 30 MHz. Vertical polarization is superior to horizontal polarization for surface wave propagation. Wave tilt occurs at the earth's surface and changes the orientation of vertically polarized ground waves, causing them to contain both vertical and horizontal electric field components that are out of phase, converting the wave to elliptical polarization.

1. wave propagation
Prepared by
b.s.nageswararao
Asst professor
Eswar college of engineering
Narasaraopet
Andhra pradesh
UNIT-VI

2. Propagation Modes
Ground-wave (< 2MHz) propagation
Sky-wave (2 – 30 MHz) propagation
Line-of-sight (> 30 MHz) propagation

14.  v

23. Superior to horizontal polarization
for surface wave propagation

25. Wave tilt
Change of orientation of the
vertically polarized ground wave
at the surface of the earth

26.  Wave tilt occur at the surface of the earth
 Tilt depend on conductivity and permitivity of the
earth
 It causes power dissipation
 Due to tilt contain both vertical and horizontal
components of electric field
 These two components not in phase
 Wave tilt cange orgional vertical polarization into
elliptical polarization wave