Lose 4G signal with WiFi connected, turn WiFi off - get 4G signal back

[ja12]

Hello:
I received this recently and noticed the 'H' to the left of the signal bar at the top of the screen disappears when I am connected to WiFi- if I turn WiFi off within a few seconds the 'H' comes back. I still have cell service but it seems I lose the 4G signal. Is this a power saving feature?

 

[N4Newbie]

All phones (that I am aware of) favor a Wi-Fi data connection when available over a cellular data connection. That is to say, if you have a working (and presumably free) Wi-Fi connection, your phone will not make use of cellular data, essentially turning it off. That's why your phone drops 4G/LTE/HSPA whenever you have a working Wi-Fi connection.