VHF waves propagate in a straight line from the transmitter in the direction of radiation. The radiation range corresponds to the visible range. However, VHF waves transmitted into free space are also reflected by ionized atmosphere and return to the earth's surface. With this technique, the curvature of the earth can be bypassed and the range of radio propagation can be significantly increased.
Amateur radio takes advantage of this phenomenon by using the ionization of meteorite tracks that have penetrated the atmospheres to reflect radio waves. The whole thing happens in a relatively small time window, both in terms of meteorite activity and the time that the ionization lasts. For this reason, one transmits at internationally agreed times. With the meteor scatter technique, radio contacts can be made far beyond the visible range.