I have been collecting the locations of ADS-B GBT (Ground Based Transceiver) locations. I tried to get this information from the FAA, but they declined. So I have been crowd sourcing the information from pilots who have the ForeFlight App and a Stratus ADS-B receiver. They are able to display the latitude and longitude of all GBT locations being received at the time and have provided me with screen shots that I enter into my ForeFlight iPad as user waypoints. Other applications and ADS-B receivers are capable of providing this information, but so far, only ForeFlight provides an actual position of the stations. Pretty much all of the applications provide a graphic presentation as does ForeFlight, but this doesn't lend itself to determining the locations, so I have only used ForeFlight for this purpose. As of this post, I have collected the locations of 459 GBT stations. All of these are now saved in a file that I am now sharing with others. The file can be downloaded and if you click on it, it will open Google earth and show the locations. Also, the file can be downloaded to ForeFlight as a collection of user waypoints. Since I don't yet have all the roughly 800 planned stations, it is helpful for those who have ForeFlight to know which ones I have already been provided and to identify new stations that can be added to the collection. Previously, the pilot had to periodically do a screen shot of the station locations and email that to me. I then had to determine if any were new or not and add just the new ones. This should make it easy for a pilot to see a new station that isn't included and send it to me. If you wish to send me screenshots from ForeFlight, please send them to my email at firstname.lastname@example.org. Also, please please please please change the ForeFlight setting for displaying latitude/longitude from the default setting of DD.dd to DD MM SS, otherwise I won't be able to plot them. The instructions for downloading the file https://dl.dropboxusercontent.com/u/58910037/user_waypoints.kml to ForeFlight are found at http://www.foreflight.com/support/user-waypoints The name of the waypoints is of my own invention, except for Alaska where I used the FAA names. For the names in the CONUS, I used the following conventions: 1) If the GBT was not located at an airport, I used the two character state identifier followed by a sequential three digit number, so NC001 is the first one I recorded in North Carolina and NC005 is the fifth one I recorded. Florida was an exception because ForeFlight treated FL as Flight Level, so I used FLA followed by a two digit number. 2) If the GBT was located at an airport, I used the ICAO code for the airport eliminating the leading K and adding a two digit number starting at 00. The reason I did this was that some of the larger airports have two to four GBT locations and I needed to use a user waypoint identifier that would not conflict with the ICAO identifier. If the airport was of the three character variety, I used the airport ID with a letter A appended to the name for the same reason, to distinguish it from the airport. Even if you don't have ForeFlight, you can view the locations using Google earth by downloading the file and clicking on the download. Here is a screenshot from my computer for the locations I have collected.