Propagation of Low Frequency LF or Long Waves Long radio waves is dependent upon:

1
Long (Surface) Wave (100 Hz-200KHz)
Propagation   All LF transmissions are
vertically polarized, only., Adcock, 1991  

• Propagation of Low Frequency (LF) or Long Waves
  (Long radio waves) is dependent upon
• surface waves and
• waves reflected between the ground and the
  ionosphere (HF as well)

References   Adcock, J. A., Propagation of
Long Radio Waves, Amateur Radio, September,
1991.   DeMinco, Nicholas, Propagation
Prediction Techniques and Antenna Modeling
(150-1705 kHz) for Intelligent Transportation
Systems (ITS) Broadcast Applications, IEEE
Antennas and Propagation Magazine, 42, August
2000.
2
Long (Surface) Wave (100 Hz-200KHz)
Propagation   General LF propagation Diagram
nighttime propagation paths J. A. Adcock,
Amateur Radio 1991

• Surface wave is composed of several components
• Direct
• Reflected
• Diffracted from edge of wave shadow zone

3
Long (Surface) Wave (100 Hz-200KHz)
Propagation Formation of Surface Wave J. A.
Adcock, Amateur Radio 1991
1) Energy is lost at ground Total Cancellation
with phase inverted direct and reflected waves
4
Long (Surface) Wave (100 Hz-200KHz)
Propagation   Factors Affecting Ground
Losses   Attenuation of vertically polarized
surface wave is related to wave tilt
Ground losses are low ü At low frequencies
becoming lower with increasing frequency. ü With
high conductivity and permittivity of surface  
5
Long (Surface) Wave (100 Hz-200KHz)
Propagation   Median Ground Constants that affect
LF loss
Ground constants for different media types
6
Long (Surface) Wave (100 Hz-200KHz)
Propagation   Path Loss for 200KHz and 1.8 MHz
for different ground media J. A. Adcock, Amateur
Radio 1991  
7
Long Wave (100 Hz-200KHz) Propagation   Path
field strength for 196 kHz (100 watts transmitted
power) J. A. Adcock, Amateur Radio 1991
Combined surface and ground wave loss for 196
KHz.over poor ground.