Car Radio Waves & Doppler Effect: Disruption?

[Anzas]

if a car with a radio is moving at some speed and it receives radio waves shouldn't these waves get Doppler shifted and the radio signal be disrupted?

 

[Tide]

if a car with a radio is moving at some speed and it receives radio waves shouldn't these waves get Doppler shifted and the radio signal be disrupted?

Yes, the radio waves are doppler shifted but the shift depends on the ratio of v/c which you can see leads to a VERY tiny shift (put some numbers into convince yourself!) The shift is entirely negligible compared with the bandwidth of any radio signal.

 

[mathman]

In theory yes. However car speeds are around 2 - 3 meters per sec, while the speed of light is 3x10⁸ meters per sec. FM signal is typically 10⁸ cm. A 2 - 3 cm shift would not be noticed.

 

[sal]

if a car with a radio is moving at some speed and it receives radio waves shouldn't these waves get Doppler shifted and the radio signal be disrupted?

For AM broadcasts you can be 'way off in the frequency and still demodulate the signal acceptably.

For FM broadcasts, it's so hard to keep a typical receiver on frequency that nearly all of them "lock onto" the signal and then follow it if the frequency shifts. Typical radios, particularly car radios, will follow the signal far from its "home frequency" before they give up on it. (Actually, this behavior probably falls out of the use of a phase locked loop to demodulate the signal -- once it's locked onto a particular signal it tends to stay there.)

So, combined with the fact that the shifts are very, very tiny, as other posters have already pointed out, the effect will be totally undetectable.

 

[Gonzolo]

A car actually goes 20-30 meters per second mathman (65 mph is roughly 30 m/s).

 

[NoTime]

The shift is enough to get you a traffic ticket as this is how radar works.
Radar is just a specialized form of radio.