The dipole antenna is made from two lengths of straight wire and can be arranged horizontally or vertically. Depending upon its orientation, a transmitted wave will either be horizontally or vertically polarized. When using a dipole it is important to make sure that both receiving and transmitting antenna have the same orientation. Outside the near field, is the region known as the far field. This is where all measurements of field strength should take place.
Many radio receivers have a manual which includes a specification sheet.
In practise, there are losses in coupling the signal from transmitter to antenna, and also losses in the antenna itself. In the next section there are examples of transmitted and received signals. In theory and travelling through space, once started a radio wave will carry on forever. However, in the real world, an EM wave is attenuated by the atmosphere and other factors. Whatever power is used for transmission, the received signal gets weaker the further the distance from transmitter.