Sky wave propagation involves radio waves reflecting off ionized layers in the upper atmosphere, called the ionosphere, between 50-400km above the Earth's surface. This allows radio signals to travel beyond the horizon over very long distances of thousands of kilometers. The ionosphere is divided into D, E, and F layers based on ionization density, with the F layers primarily responsible for radio wave refraction. Sky wave propagation has enabled long-distance shortwave radio communication between 3-30MHz and amateur radio communication over long distances.

1. -Maheshwari
Das
Meghana BS

2. Wave propagation is any of the ways in
which waves travel. With respect to the
direction of the oscillation relative to
the propagation direction, we can
distinguish between
longitudinal wave and transverse waves.
For
electromagnetic waves, propagation may
occur in a vacuum as well as in a material
medium.

5. Propagation of radio waves from
a radiating transmitting antenna
to the receiving antenna may
take place in one of the
following routes:
1. Ground wave propagation
2. Sky wave propagation
3. Space wave propagation

10. Sky-wave propagation

11.  It is also called Ionosphere
propagation
 I this mode of propagation
the EM eaves reaches the
receiving point after
reflection from the ionized
region in the upper
atmosphere called
ionosphere.
 Ionosphere is situated
between 50km & 400km
above the earth. It is divided
into three basic layers (D, E
& F) based on ionization
density. F layer is further
divided into F1 and F2 sub
layers.

13.  D & E layers are
weekly ionized &
exist only during day
light hours. They
tend to observe
medium waves .
 The primary effect
of F layers is to
cause refraction of
Radio waves.

15. Ionosphere
propagation
permits extremely
long distance
communication
3MHz-30MHz
range
Above 30MHz
frequency signals
are not reflected.

16.  Most long-distance
shortwave radio
communication—between
3 and 30 MHz—is a
result of sky
wave propagation.
 Since the early 1920s
amateur radio operators
, limited to lower
transmitter power than
broadcast stations, have
taken advantage of sky
wave for long distance
communication.
 The signal received are
subjected to fading, in
which signal strength
varies with time.
 The receiving point, a
large number of waves
follow a different
number of paths

17. Short wave, AM radio
broadcast.
Long distance, point to point
communication.
Extremely long distance
communication using multi-hope
propagation.