I use the OpenSignal app to do the same thing. It works for both wifi and 4G depending on what you have enabled on your device at the time you’re using it. But remember, the signal finding app is limited to the signal that your cell phone or tablet is getting at the time you’re using the app, not the possible signal that a cell phone booster might find for you. In other words, there might be a usable signal out there but your ground situated device might not see it.

Perhaps you could look into some of the cellular boosters on the market and combine it with yagi (directional) antenna.

Thanks

I use an app called Network Signal https://play.google.com/store/apps/details?id=de.android.telnet&hl=en_CA&gl=US I think it's only for Android though.

I do most of my camping on the east coast but cell signal can be worse here than out west. In the west, most towers are situated for maximum coverage. in the east they are placed in towns where the most people are.

I use Opensignal and Network Signal and play with a few others. The more I try to get a good signal the harder it gets. This app says to point your directional antenna this way and another app says to point it another way. (If there are competing poor signals my phone keeps switching between them looking for the best signal.)

Out west there was usually a clear winner.

I got a good omni-directional antenna and put it on top of a tall flag pole and with the booster it usually does the trick.