PS-43 is composed of two sub-arrays (Ankara and Keskin) is shown in Figure the medium-period array with » 40 km radius located in Ankara and the short-period array with » 3 km radius located in Keskin. Each array has a broadband element located at the middle of the circular geometry. Short period instruments are installed at depth 30 meters from the surface while medium and broadband instruments are installed at depth 60 meters from surface. Freewave Wireless Data Transceivers which form the basis of RDL provide intra-site communications from all instrument sites. The data from both arrays comes to CRB (Central recording Building) and data is sent to IDC via satellite (VSAT) whereas KOERI (Kandilli Observatory and Earthquake Research Institute) and AFTAC (American Air Force Technicial Application Center) receive the data via telephone lines.