L-5, broken at the center point
for connection to the variable condenser C-1. The coil L-7 connected to
the loop B is similarly connected. Both L-5' and L-7 are coupled to the
secondary coil L-6 which is broken at its center to include the variable.
condenser C-2.
The arrangement of the three
coils at the receiving station was. similar to that employed in the Bellini-Tosi
goniometer shown in figure 7, wherein the rectangular frames L-5 and L-7
are stationary and the rotating frame L-6 is mounted on a vertical axis
so that it can be ro-tated within the resulting magnetic field.
It may be well to describe here
the preliminary pro-cedure of adjustment: The coil L-6 is first placed
in inductive relation with L-5 of loop A and the incoming signal tuned
to maximum intensity. Next, coil L-6 is placed in inductive relation with
L-7 of loop B, which circuit is also tuned to maximum signal intensity.
Both loops are then connected in and coupled to the coil L-6 which is turned
on its axis to receive the maximum induction from both L-5 and L-7. The
two primary coils pro-duce a resultant magnetic field which acts upon the
rotating coil somewhat after the principle of the radio goniometer.
HOW THE STATIC ELIMINATOR WORKS
An explanatory diagram of the system of figure 6 ap-pears
in figure 8. Here the two closed circuit loops of figure 6 shown as A'
and B' are coupled to a common secondary coil L-3 of the receiving apparatus
which is installed in a station placed between the loops. The vertically
propagated static waves are indicated by the downward arrows above the
loops and the advancing signal waves which, in this diagram, are assumed
to pass from left to right, are represented by the arrows A, A, A, A.
If static waves are propagated vertically, it is clear
that they act upon loops A' and B' simultaneously and con-sequently electro-motive
forces of equal intensity are generated in both loops and the static currents
resulting therefrom flow in the same direction in each loop, as in-dicated
by the single pointed arrows. For. purposes of illustration, we have assumed
that the static currents flow clockwise in the two loops as shown in the
diagram. The current in loop A' flows downward through the coil L-1 and
that in loop B' upward, through the coil L-2. The
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two currents will therefore neutralize
and consequently none of the static current will flow in the coil L-3.
It now remains to be seen how
a useful part of the energy of the signal wave is retained. From figure
8 it is evident that the signal wave acts upon the loop A' before arriving
at the loop B'; and we may assume, for the pur-poses of illustration, that
the arrows A represent the progressive movement of the advancing wave.
As the wave motion progresses and the positive half acts upon the loop
B', the negative half of the wave is acting upon loop A'. We will assume
that, at a particular moment, its polarity is such that in loop A' the
static current and the signal current pass in the same direction through
the coil L-1. The signal and static currents must therefore flow in opposite
directions in the loop B'; and inasmuch as coils L-1 and L-2 are coupled
to L-3 in such a way that the static currents oppose and neutralize, the
signal
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