Mastdata is an application that enables users to find out where mobile masts are located in the UK.  The app works in a number of ways. When you start the app, you will enter a location and it will then display a map of the area you have selected.

When you have selected a mast, you can see the details of the station including the operator, site reference, and line of sight summary. If you want to take a look at the results of the survey you can see the results on the device you are using.