Complex sentence: It is applied in particular for aerials for VLF, longwave and medium-wave transmitters, because radio waves are several hundred meters to many kilometers long, mast radiators of the necessary height cannot be realised economically.
Split into simpler sentences: It is applied in particular for aerials for VLF, longwave and medium-wave transmitters. Because those radio waves are several hundred meters to many kilometers long, mast radiators of the necessary height cannot be realised economically.