The world's largest radio telescope, which has been built in China, is beginning an intensive testing phase. <br/><br/>Chinese scientists report that the giant dish is complete and has received its first signals from space. It will now take three years to calibrate the instrument to become fully operational. The facility, part of China's drive to become a science powerhouse, was opened at a ceremony today.<br/><br/>The radio telescope, located in a vast natural crater in Guizhou Province in southwest China, has been an ambitious project for the National Astronomical Observatories of China.