negative half of the signal wave
acts upon B', and the positive half on A'.
The foregoing may be stated
in another way by saying that the static waves arrive at the two aerials
at the same time, while the signals arrive at the two aerials at different
times. Therefore the static currents in the two loops at any instant
are in phase and the signal currents are out of phase by an amount depending
upon the effec- |
waves will always give a resultant
depending, upon the effective separation of the loops; that is, the distance
from center to center of the loops. If this separation is one-half wave
length, the E.M.F.'s generated in the coil L-3 by the signal currents from
loops A' and B' will be in phase and the resultant is therefore equal to
the arith-metical sum of these two E.M.F.'s. If the loop separation
is equal to one-quarter wave length, then the E.M.F.'s acting on the coil
L-3 will be 90 degrees apart and the |