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## Homework Statement

1. Tune the Antenna Consider an AM radio station broadcasting at the frequency 1500

kHz, and wavelength 200 m.. Suppose the station has two antennas separated by 80m, one north

of the other.

a) (2 pts.) If the two antennas broadcast their signals in phase with each other, what is the phase

difference (in radians) of the radio waves arriving at a point north of the two antennas?

b) (4 pts.) If the two antennas broadcast their signals in phase with each other, what is the ratio

of the intensity of the radio signal at a point north of the antennas to the intensity east of the

midpoint between the antennas? (Both at the same long distance from the center of the antennas.)

c) (4 pts.) Suppose we want the maximum intensity in the antenna radiation pattern to lie on the

line running frm North-East to South-West, 45 degrees from north. What must be the phase difference

between the signals broadcast from the two antennas?

a) phase difference = (2pi/wavelength)(r2-r1)

I picked the point 20m from s1 and 100m from s2 so

phase difference = (2pi/wavelength)(100m-80m) = 12.56deg or .213rad

b) I kept the same point for the one north of the antennas. since they say from the midpoint east; 40m and then I did 40m to the east or -x.

I = I_o cos^2 (phase dif/2)

North point intensity = I = I_o cos^2 (12.56/2)

East from mindpoint = I = I_o cos^2 (0)

so the ratio is 1?

c) Help please :)