If your a cb'er or ham operator or swl listener its a well known
fact that durring the summer months when the skip is rolling it is
possible to recieve signals hundreds or evan thousands of miles away on hf frequencies
(1-30 MHz). This is known as skip or skywave propagation. Skip is caused by radio waves
being bounced off the ionosphere and returning to earth at great distances from the transmitter.
Durring the day time radiation from the sun causes gasses in the atmosphere to become charged
this process is called ionization. Ionization of the ionosphere acts as a giant mirror for HF frequencies
the signals bounce of the ionosphere and return to earth hundreds or evan thousands of miles away from the
transmitter. Also the sun spot cycle has a big effect on skip currently we are about peak the 11 year cycle
in the year 2001. Sun spots cause the atmosphere to become evan more exited and can intensify skip. If you have
currently turned on a CB radio you know that the skip is so bad in the day time you can hardly talk across town.