Bernard Mills built the two-dimensional Mills Cross Telescope in the early 1950s. Each arm of the cross was 1500 feet long and produced a fan beam in the sky. When the voltages of the two arms were multiplied a pencil beam was formed, but with rather high sidelobes. The beam could be steered in the sky by adjusting the phasing of the elements in each arm. Operating at 3.5 m (86 MHz), the resolution of the Mills Cross was about 1°. Following the success of this design, Mills built a large cross antenna near Canberra, the Molongolo Cross Telescope. Other large cross-type radio telescopes were later built in Italy, Russia, and the Ukraine.