Antenna Two Way Radio

Two radio antennas A and B radiate in phase. Antenna B is a distance of 110 m to the right of antenna A. Consider point Q along the extension of the line connecting the antennas, a horizontal distance of 50.0 m to the right of antenna B. The frequency, and hence the wavelength, of the emitted waves can be varied

Part A
What is the longest wavelength for which there will be destructive interference at point Q?

What is the longest wavelength for which there will be constructive interference at point Q?

Sorry this all I had time to get.not ans.
λ = 300,000,000/f
Destructive interference occurs when 1/(nλ)^2 = 1/(λ(m + 1/2)^2, or 1/(n)^2 = 1/(m + 1/2)^2

2008-11-19 01:25:01 by Sidhucer

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2007-09-19 20:05:10 by meterman

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The two antennas radiate in phase at a frequency of 5.6 MHz. All radio measurements are made far from the antennas. The smallest angle, reckoned north of east from the antennas, at which destructive interference of the two radio waves occurs, is closest to:

a) 13 degrees
b) 9.7 degrees
c) 19 degrees
d) 6.4 degrees
e) 16 degrees

λ = 300,000,000/5,600,000 = 3000/56 m
λ/2 = 1500/56
200/λ = 56/15 cycles
Now the question becomes, "measured North of East from where?".
Destructive interference occurs when 1/(nλ)^2 = 1/(λ(m + 1/2)^2, or 1/(n)^2 = 1/(m + 1/2)^2

2007-04-02 02:19:32 by The one and only

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The two antennas radiate in phase at a frequency of 3.6 MHz. All radio measurements are made far from the antennas. The smallest angle, reckoned east of north from the antennas, at which constructive interference of two radio waves occurs, is closest to:

a) 50 degrees
b) 40 degrees
c) 45 degrees
d) 55 degrees
e) 35 degrees

this is Young interference problem with radio waves

if you consult your textbook you will find

dsin(theta)=k(lamda) for constructive interference
here k=1 because it is said that it is the first max (smallest angle) lamda is the wavelenght of the radiation, and d=130m,

lamda=c/f where c=speed of light in meters, and f=frequency in hertz

so

sin (theta)= lamda/d

here lamda= 83 meters
then sin (theta)=83/130 then theta=40 degrees

2007-04-02 02:13:05 by The one and only

If a friend asked you to explain the difference between the way data travels in a wire and radio waves sent from an antenna, what would you tell them? How would you demonstrate these two communication methods to that friend?

Basically, data travels through an electrically conductive wire via electric currents - these currents exist at a given frequency and this frequency is modulated in the proper way to carry the information required.

Radio waves are different, in that the phenomenon is more complex.

Radio waves are *electromagnetic* radiation, which consists of perpendicular fields of electric and magnetic force interacting with each other - these are subsumed under Maxwell's equations which is a formalization of electromagnetic phenomena.

Electromagnetic waves have a given frequency in Hertz, which are modulated in the appropriate way to carry the information needed - this could be Amplitude Modulation (AM), Frequency Modulation (FM), or Single Side Band (SSB), and a number of other forms of modulation are possible also.




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2007-07-21 04:26:52 by Sexy R