Shortwave two-way radio

Short wave 2 way radio is a kind of radio, use frequency is short wave. Short wave of basic transmission way has two: one is the ground wave, one is heaven wave. As stated above, the surface of the earth spread along the ground, the transmission distance depends on the surface medium characteristics. The sea of medium for radio waves propagation characteristics to conductivity most favorable, short wave signal can be ground coastal face spread about 1000 kilometers; The land surface medium poor conductance characteristics, the waves attenuation, and different land surface media on the waves of the attenuation rate is not (the moist soil ground attenuation small, dry sand ground attenuation big). Short wave signal propagation along the ground can be at most a few tens of kilometers. Ground spread don’t need to change often work frequency, but want to consider the obstacles blocking, this heaven wave spread is different. The main transmission way shortwave is heaven wave . Short wave signal the antenna is issued, the ionosphere reflected back to the surface, and the ground reflected back to the ionosphere, can reflect many times, and spread far distance.