That's true. Nevertheless, in my "indoor" test I keep all other radios: BT and Wi-Fi switched off.
That's not a big deal, but I am just curious why the GPS is so hard to get and also the GPS signal vanishes immediatelylty when I enter the car/train/building... In the case of Garmin I can still rely on GPS signal at least inside the car and the train - TwoNav requires to be so close to the window...
Maybe, it is somehow connected with the bulit-in anthenna position (?)...
Edit #2:
In my case, the GPS signal vanishes immediately under even small bridge, tunnel, etc.