Measurement of cosmic ray air showers using MHz radio-detection techniques at the Pierre Auger Observatory

The measurement of radio signals from air showers is studied in detail with the Auger Engineering Radio Array (AERA) at the site of the Pierre Auger Observatory in Argentina. The first stage of AERA is in operation since March 2011 and consists of 24 autonomous radio detector stations. The design of the stations including the radio antennas, the electronics system and the communications system is presented. In the next 12 months AERA will grow to a size of 125 stations covering an area of about 16 km2. First results and improvements for this next stage of AERA will be discussed.