Belbasi Arrays (Treaty code: PS-43) is composed of two sub-arrays (Ankara and Keskin) is shown in the below Figure the medium-period array with a 40 km radius located in Ankara and the short-period array with a 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 the surface. Freewave Wireless Data Transceivers which form the basis of RDL provide intra-site communications from all instrument sites. The data from both arrays come to CRB (Central recording Building) and data is sent to IDC via satellite (VSAT) whereas KOERI (Kandilli Observatory and Earthquake Research Institute) and AFTAC (Air Force Technical Application Center) receive the data via telephone lines.
Data availability of BRTR-PS43 since 2004 has been given in the below figure. Microwave Systems were only available for 2004 and late 2005 and were replaced by RDL (Radio Data Link) Systems. Data availability shows variety but an increasing trend to the year 2020 due to improvements in the data acquisition related to RDL equipment. The horizontal red line in the figure indicates the IMS requirement limit (98%) for data availability. IMS stations are expected to satisfy this limit to be considered mission capable.
There are 4 types (6dB,15dB,21dB, and 24 dB) of antennas that are currently used in the communication system of BRTR. 6 and 15dB antennas for short, such as SP Array (~2 km radius), 21 and 24dB antennas for long such as MP Array (~20 km radius). The distance between SP and MP array is approximately 60 kilometers line.