On the nature of wireless signal variations. —II

The present paper continues the account of investigations on the nature of signal fading given in paper I of similar title. As the argument is essentially continuous from paper I to paper II the numbering of equations, tables and figures has been made to run continuously from the former to the latter paper. 2. Direct Investigation of the Downcoming Waves by suppression of the Ground Waves . ( a ) Theoretical Considerations . —The ordinary curves of signal intensity variation obtained either with a vertical aerial or with a loop in the plane of propagation do not give us directly the variations in amplitude of the downcoming waves because we are unable to deduce from them whether a particular signal variation is due to a change of phase or a change of amplitude. We can, however, investigate the changes in intensity of the downcoming waves if we suppress the ground waves. This may be done by using the particular combination of loop and vertical aerial discussed below.