I have a magnet mount Sirio Performer 5000 center mounted on my truck.
I'm running an anytone 6666.

The radio has a SWR function and standing still I have the antenna tuned to 1.0 SWR on the radio and with Motorola meter
If I'm driving over 45-50 mph the SWR can read from 2.7 - 3.9

#1, is that normal?
#2, is an SWR reading only from stationary?

I don't think there is any water under it. If I slow down, the reading drops.

I just don't want to cook the finals.