Can anyone suggest the dongle that can cover most of the building or maybe there is another way around on delivering the data from the web server? Except for hosting the server online. The system will be used on different schools here in my place that's why I need to consider a lot of things to make...

I'm planning on using Raspberry Pi as a local web server for the examination system that I want to develop, the device that will fetch the data from the web server will be an android tablet, the problem is I don't have any idea if the Pi can cover the whole building with no problem. I know the signa...