For example; a radar with 1 degree beam width and a target at 120 km (75 mi) range will show the target as 2 km (1.2 mi) wide. To produce a 1-degree beam at the most common frequencies, an antenna 1.5 kilometres (0.93 mi) wide is required. Due to the physics of the refraction process, actual accuracy is even lower, with range resolution on the order of 20 to 40 kilometres (12–25 mi) and bearing accuracy of 2 to 4 kilometres (1.2–2.5 mi) being suggested.