Help! whats the speed of a radio wave?

thawolfman

Lifer
Dec 9, 2001
11,107
0
76
google works wonders ;)



<< If there is an object in the path of the radio wave, it will reflect some of the electromagnetic energy, and the radio wave will bounce back to the radar device. Radio waves move through the air at a constant speed (the speed of light), so the radar device can calculate how far away the object is based on how long it takes the radio signal to return. >>

 

dude

Diamond Member
Oct 16, 1999
3,192
0
71
No, definately a far cry from the speed of light.

FM waves travels at different speeds depending on their wavelength. Same with AM.
 

thEnEuRoMancER

Golden Member
Oct 30, 2000
1,415
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71


<< No, definately a far cry from the speed of light.

FM waves travels at different speeds depending on their wavelength. Same with AM.
>>



You must be talking about sound waves.

Radio waves are electromagnetic waves, travelling at the speed of light in the air - 299 702 547 m/s.
 

Linflas

Lifer
Jan 30, 2001
15,395
78
91


<< No, definately a far cry from the speed of light.

FM waves travels at different speeds depending on their wavelength. Same with AM.
>>


AM/FM refers to the method used to encode information/sound for broadcast and has no bearing I am aware of on speed. AM is a set frequency and the sound information is contained in the amplitude of the wave. FM has a center frequency and the sound information is represented by the variation in frequency around the center frequency. That is why FM is noise free when compared to AM.
 

ttn1

Senior member
Oct 24, 2000
680
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0
Actually the speed of a radio wave in air would be the speed of light in a vacuum multiplied by the refractive index of air. Depending on the accuracy required for your calculation, the refractive index of air is 1.000293.

The number I have for the speed of light in a vacuum is 2.99792458*10^8 m/s.