Lower frequency radio waves, below 3 MHz, travel efficiently as ground waves. As losses increase with frequency, high frequency transmissions between 3 and 30 MHz have more modest groundwave range and groundwave is unimportant above 30 MHz. Surface conductivity affects the propagation of ground waves, with highly conductive surfaces such as sea water providing the best propagation, and dry ground and ice performing the worst.
Lower frequency radio waves, below 3 MHz, travel efficiently as ground waves. As losses increase with frequency, high frequency transmissions between 3 and 30 MHz have more modest groundwave range and groundwave is unimportant above 30 MHz Surface conductivity affects the propagation of ground waves, with highly conductive surfaces such as sea water providing the best propagation, and dry ground and ice performing the worst.