Abstract

In its first phases radio astronomy was restricted to frequencies of about 30 MHz to 3 GHz (wavelengths of roughly 10 meters down to 0.1 meters), but since the 1960’s the ‘high frontier’ of the field has moved successively to tens, then hundreds and now thousands of GHz, i.e. to cover the millimetre and sub-millimetre wavebands. This advance has been largely driven by technological developments – for example in the design of antennas and receivers – and by the opening up of suitable observing sites. At the same time the scale of these activities has expanded from the level of individual efforts to that of worldwide collaborations. The lecture will outline the key steps in this evolution and describe some of the dramatic scientific discoveries that have followed.