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Propagation

Introduction

Radio waves, like light waves and all other forms of electromagnetic radiation, normally travel in straight lines. Obviously this does not happen all the time, because long - distance communication depends on radio waves traveling beyond the horizon. How radio waves propagate in other than straight-line paths is a complicated subject, but one that need not be a mystery. This page provides basic understanding of the principles of electromagnetic radiation, the structure of the Earth's atmosphere and solar-terrestrial interactions necessary for a working knowledge of radio propagation. More detailed discussions and the underlying mathematics of radio propagation physics can be found in the references listed under additional resources.

The Sun, being the largest engine in our solar system, has a great effect on propagation as its "exhaust" interacts with our Earth's magnetic field. A rudimentary knowledge of sunspots, solar flares and mass ejections will help the amateur take advantage of these effects to enhance his pleasure, or understand his plight. A good basic understanding of this can be had by reading the article "The Sun, the Earth, the Ionosphere." See also the list of other articles on propagation.

You can get custom professional-grade high-frequency (3-30 MHz) propagation predictions online.

Where can I find solar data?

Mark Downing, WM7D, has graphs of solar data on his web site.

Current HF Propagation Charts

Highly  recommended reading for understanding these charts.

"Those New QST Propagation Charts," by Jerry Hall, K1TD

"Interpreting QST's New Propagation Charts for Low Power and Low Antennas," by Jerry Hall, K1TD

November 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 71.

 

October 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 70.

 

September 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 69.

August 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 68.

July 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 67.

June 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 66.

May 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 66.

April 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 73.

 

March 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 73.

February 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 73.

 

January 2018

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 73.

 

December 2017

East Coast

Midwest

West Coast

Alaska Hawaii

These predictions are for a solar flux of 73.