Two antenas (two waves wih the same frequency)

In summary, the conversation involves discussing the problem of calculating the phase difference between two antennas broadcasting radio waves at a certain frequency. The conversation also includes finding the distance at which the first destructive interference occurs and how many times it will occur as an observer walks along the x-axis. Several equations and calculations are discussed to find the answers to these questions.
  • #1
9
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i really have some proplem with this question

Two antennas located at points A and B are broadcasting radio waves of frequency 95.0 MHz, perfectly in phase with each other. The two antennas are separated by a distance d= 9.30 m. An observer, P, is located on the x axis, a distance x= 60.0 m from antenna A, so that APB forms a right triangle with PB as hypotenuse. What is the phase difference between the waves arriving at P from antennas A and B?

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Now observer P walks along the x-axis toward antenna A. What is P's distance from A when he first observes fully destructive interference between the two waves?

If observer P continues walking until he reaches antenna A, at how many places along the x-axis (including the place you found in the previous problem) will he detect minima in the radio signal, due to destructive interference?

i calculated the phase difference between the two antenas but i didnt know how to to calculate the first time that i will receive a destructive interfernce i think that it is when the phase difference is pi*(2m+1)

this is how i calculted the first quesion first i calculated the distance BP which is 60.716m
then i used the equation (phase difference=2*pi*delta L/ג ) delta L=BP-AP and ג=c/frequency which is given
 
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  • #2
You have already found ΔL. If at the point P instructive interference takes place, then
ΔL = (2n + 1)*λ/2. ...(1)
Find the wavelength.
Substitute the value of the wavelength in eq(1) and find n. If n is not an integer, at P there is no destructive interference. Select the nearest integer less than n. That is the first point of destructive interference with in 60 m.
 
  • #3
hi
I tried to do what you told me but it does not help when i calculated n its negative and after i calculate n how can I calculate the distance AP I attached my try to solve the proplem
 

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  • #4
ΔL = (2n + 1)*λ/2. ...(1)
Find the wavelength of the radio wave.
The first destructive interference will occur when ΔL = λ/2.
Now ΔL = sqrt(9.3^2 +x^2) - x...(2)
Put ΔL = λ/2 and solve for x.
Repeat the procedure for ΔL = 3λ/2, 5 λ/2...until x becomes negative.
 
  • #5
Thanks a lot

I understand the proplem x is AP and I repeat the procedure to know how many time i have a destructive interfernce

if there is anything i can help with
 

What is the concept of two antennas with the same frequency?

The concept of two antennas with the same frequency is known as interference. This occurs when two waves with the same frequency and amplitude are present in the same space. This can result in constructive or destructive interference, depending on the phase relationship between the two waves.

How does constructive interference occur in two antennas with the same frequency?

Constructive interference occurs when two waves with the same frequency and amplitude are in phase, meaning their peaks and troughs align. This results in a larger amplitude and stronger signal. In the case of antennas, this can improve the overall signal strength and reception.

What happens when two antennas with the same frequency are out of phase?

When two antennas with the same frequency are out of phase, destructive interference occurs. This means that the peaks of one wave align with the troughs of the other, resulting in a cancellation of the waves. In the case of antennas, this can lead to a weaker signal or complete loss of reception.

Can two antennas with the same frequency interfere with each other?

Yes, two antennas with the same frequency can interfere with each other. This is why it is important to properly space out antennas to avoid interference. Additionally, using antennas with different frequencies can also help prevent interference.

What are some real-world applications of two antennas with the same frequency?

Two antennas with the same frequency are commonly used in radio and television broadcasting. By using multiple antennas, broadcasters can increase their signal strength and reach a larger audience. This is also used in cell phone networks to improve signal strength and coverage.

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