Is this normal?

I have an 05 Sc. When I turn on the radio the power antenna extends all the way up and after it is fully extended it immediately goes down about two sections.

Also I notice when I pass 96 on the fm dial it goes up or down about another 3 inches

Can someone tell me that both of these occurences are normal and why it happens

Thanks,
Mario

 

It is normal. The antenna is adjusting its length for the tuned frequency to provide better reception.