All considerations, when calculating the radar equation, were made assuming that the electromagnetic waves propagate under ideal conditions without disturbing influences. In practice, a number of losses should be considered since they reduce the effectiveness of the radar considerably.

First, the radar equation is extended by including the loss factor .

This factor includes the following losses:

High-frequency components, such as waveguides, filters and also a radome, generate internal losses. For a given radar set this loss is relatively constant and also easily measured.

Atmospheric attenuation and reflections at the Earth's surface are permanent influences.

An extended but less frequently used form of the radar equation considers additional terms, like the Earth's surface but does not classify receiver sensitivity and atmospheric absorption.

In this equation, in addition to the already well-known quantities are: