Furuno NX-700B Service Manual page 86

Reference;
Letting the voltage magnitude (VA) induced in the antenna coil A in the direction of
maximum sensitivity = "1",
VA=Sinθ
Letting the voltage magnitude (VB) induced in the antenna coil B in the direction of
maximum sensitivity = "1",
VB=Cosθ
Letting the high-frequency voltage induced in the antenna coil A = VA Sinωt, the
high-frequency voltage induced in the antenna coil B = VB Sinωt or -VB Sinωt.
Hence the relation of voltage induced in the antenna coil A and B is in-phase or
reversed phase. If the high-frequency voltage induced in the antenna coil A or B is
given a phase difference by 90 degrees,
VA Sinωt
VB Sin (ωt+π/2) =VB Cosωt
When the two formulas above are added,
VA Sinωt+VB Cosωt
=SinθSinωt+CosθCosωt
=Cos (ωt-θ)
In consequence, "1" in the direction of maximum sensitivity is obtained for the
magnitude of combined induced voltages regardless of the receiving direction of
radio wave.
5-15
5.3 Block Description