I was playing with the PiFm on my Pi and successfully transmitted the sound.wav on a specific frequency. That is 94.5 . But when I am trying to do the same on 89.7 , it does nothing. I changed absolutely nothing but the frequency.

What would be the cause of this. Also...maybe not so relevant, when I ctrl+C the PiFm the sound.wav stops playing from the radio but the regular program does not return.

Thank you in advance!