Propagation VHF and Above

(an overview only)

by Rick Bandla (VE3CVG)

as presented at RAC Forum in Carp, ON on August 30, 2003

Radio Waves

The Ground - info from OZ1RH

Height above Flat Ground Ground Gain Max Radiation @
1/2 wavelength -1.7dB 13 degrees
1 wavelength +2.6dB 11 degrees
2 wavelengths +4.8dB 7 degrees
5 wavelengths +5.5dB 3 degrees

Typical beam pattern above ground. The ground influences the angle of the lobes and in particular the largest (main) lobe. pattern of beam

Ionization

When Radio Waves meet Matter

Refractive Index or N

Troposphere

Tropo Scatter

Tropo Ducting

Atmosphere Chart

layers of the atmosphere

Ionosphere

Sporadic E (Es)

Aurora (Au)

Auroral Es

Aurora Map

map showing auroral donut

Meteor Scatter (MS)

Meteor Scatter - What Works?

Summary of Propagation Modes

Medium Mode Abbrev 6M 2M 70cm Above
Troposphere Refraction Tropo
X
X
X
X
-
Ducting Tropo
-
X
X
X
-
Scatter Ts
X
X
X
X
Ionosphere Sporadic E Es
X
X
-
-
-
Auroral E Au Es
X
X
-
-
-
Aurora Au
X
X
X
X
-
F2 F2
X
-
-
-
-
Meteor Scatter MS
X
X
?
?
-
Ionospheric Scatter
-
X
?
-
-
Obstacles Diffraction
-
X
X
X
X
-
Moon bounce EME
?
X
X
X
-
Reflection
-
X
X
X
X

Polarization

So What Mode Was That?

What You Need to Succeed on VHF/UHF & Up

When's A Good Time?

chart showing best months for specific propagation

Effective Transmission Modes

WSJT by K1JT Joe Taylor

References

Web Sites

The End




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