RADIO-FREQUENCY

WAVE PROPAGATION

BY:

Rea Jhoy Lastimosa

Christian Joseph Garniel

There are three basic paths that a radio signal can take

through space

• Ground waves

• Sky waves

• Space waves

GROUND WAVES

(SURFACE WAVES)

Ground Waves

(Surface waves)

• Leaves the antenna and remains close to the earth.

• follow the curvature of the earth

• strongest at the low and medium frequency

ranges.

• 30KHz – 3MHz range

• can propagate for hundreds and sometimes

thousand of miles at these low frequencies.

Effects of the Ground

surface wave is very dependant upon the nature of the

ground of which the signal travels. Such as the ff:

• Ground conductivity

• Terrain roughness

• Dielectric constant

Effects of the ground

• at lower frequency ground penetration is

greater

• at higher frequency ground penetration is

smaller

Ground Conductivity depends on the ff.

• Soil type and the moisture content ---rich

agricultural or marshy land

• Salty sea water

• Dry sandy terrain and city centers

Classification Band Frequency Range Characteristic

Extremely low 30 - 300 Hz Ground waves

Voice Frequency 300 Hz – 3 KHz Ground waves

Very low Frequency 1.5 – 20 KHz Ground waves

Low Frequency 30 – 300 KHz Ground waves

Meduim Frequency 300 – 3000 KHz Ground/ sky waves

High Frequency 3 – 30 MHz Sky waves

Very high Frquenncy 30 – 300 MHz Space waves

Ultra high Frequency 300 – 3000 MHz Space waves

Superhigh Frequency 3 – 30 GHz Space waves

Extremely High Frequency 30 - 300GHz Space waves

Infrared > 300 GHz Space waves

THANK YOU!!!

GOD BLESS