A Distribute Antenna System (DAS) is a cell site configuration when cellular companies separate antennas from a specific tower and relocate those antennas in the areas around the tower to provide better signal coverage to places that would not be covered enough by a single group of antennas at one location.
DAS sites can be recognized in the service provider’s cell site lists by reviewing the cell sites numbers and comparing the latitudes and longitudes of the different sectors (or antennas). If the same cell site number is located at two or more different places according to the latitude and longitude this is a good indication that cell site has distributed antennas. (It should be noted that minor location differences is 500 feet or less area normal, and could be simply measurements taken by the engineer in different places around the base of the tower.
DAS configurations are common along a road in a valley where one cell site can’t produce signal to all the areas on the winding road in the valley, so antennas for that tower are placed in different spots along the road to provide the coverage but all antennas linked back to one cell site location. In this scenario the cell site name used in the CDR would be depicted as the main location of the cell site not the locations of the antenna.
Another example of where DAS antennas are frequently used is in subway systems. Because one cell site cannot produce signal in all areas of the subway line, antennas from one cell site are distributed along the path of the subway. Again, the historical records would indicate the phone used a cell site some where along the subway line, but the phone could have used any of antennas placed through the subway.
Additionally, DAS cell site configurations can be used anywhere the engineers need to provide better coverage and need to spread out the antennas. I have seen these in highly populated areas of large cities like Los Angeles covering dense housing areas.
Example of a DAS site in Metro PCS’s cell site list. Notice cell site 441 has several different latitudes and longitudes listed.