Radio Propagation - Modes

Modes

Radio frequencies and their primary mode of propagation
Band Frequency Wavelength Propagation via
ELF Extremely Low Frequency 3–300 Hz 1000-100,000 km
VLF Very Low Frequency 3–30 kHz 100–10 km Guided between the earth and the ionosphere.
LF Low Frequency 30–300 kHz 10–1 km Guided between the earth and the D layer of the ionosphere.

Surface waves.
MF Medium Frequency 300–3000 kHz 1000–100 m Surface waves.

E, F layer ionospheric refraction at night, when D layer absorption weakens.
HF High Frequency (Short Wave) 3–30 MHz 100–10 m E layer ionospheric refraction.

F1, F2 layer ionospheric refraction.
VHF Very High Frequency 30–300 MHz 10–1 m Infrequent E ionospheric (Es) refraction. Uncommonly F2 layer ionospheric refraction during high sunspot activity up to 50 MHz and rarely to 80 MHz. Generally direct wave. Sometimes tropospheric ducting.
UHF Ultra High Frequency 300–3000 MHz 100–10 cm Direct wave. Sometimes tropospheric ducting.
SHF Super High Frequency 3–30 GHz 10–1 cm Direct wave.
EHF Extremely High Frequency 30–300 GHz 10–1 mm Direct wave limited by absorption.

Read more about this topic:  Radio Propagation

Famous quotes containing the word modes:

    “The human condition is such that pain and effort are not just symptoms which can be removed without changing life itself; they are the modes in which life itself, together with the necessity to which it is bound, makes itself felt. For mortals, the “easy life of the gods” would be a lifeless life.”
    —Hannah Arendt (1906–1975)

    “Without any extraordinary effort of genius, I have discovered that nature was the same three thousand years ago as at present; that men were but men then as well as now; that modes and customs vary often, but that human nature is always the same. And I can no more suppose, that men were better, braver, or wiser, fifteen hundred or three thousand years ago, than I can suppose that the animals or vegetables were better than they are now.”
    —Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)

    “Heaven is large, and affords space for all modes of love and fortitude. Why should we be busybodies and superserviceable?”
    —Ralph Waldo Emerson (1803–1882)