There is some juicy information in the following data set. It is a collection of all known ISMI *fake cell phone towers* which passed by a few listening devices. As one sifts through the data, please be cognizant anyone with a few hundred dollars may create a fake tower. Please be careful not to jump to any conclusions.
If you would like to turn your Android device into a listening post, here is a nifty detector https://f-droid.org/repository/browse/?fdid=com.SecUpwN.AIMSICD .