Smallest and largest electromagnetic frequencies

[Constructe]

What is the smallest electromagnetic frequency and the largest possible electromagnetic frequency? Also, can small frequencies ride on larger frequencies?

Ergo. You are traveling 99.7 the speed of light away from something shooting a blue light light at you. What frequency is it? Once it erodes to the largest frequency do you see sub frequencies on it if you go faster... say 99.997% the speed of light? Now go reverse. What is the smallest frequency it becomes? If you go faster do you see it riding on a larger frequency?

Is there a physics law that defines the smallest and largest possible frequency of light/EM wave?

 

[mathman]

Is there a physics law that defines the smallest and largest possible frequency of light/EM wave?

No. Creating extremely high frequency or extremely low frequency EM radiation may be difficult, but this is because of instrumentation limitation, nothing fundamental.

 

[Constructe]

Oh thanks, because I read in a book on Einstein there was a maximum frequency of light. But that seems like it would mean that simply going away from something fast enough you basically break realativity since light frequencies can't get bigger than that frequency... Same goes with smallest frequency, but you go towards it.