How to improve the High Frequency capabilities of SRT

Astronomical Observatory of Cagliari, loc. Poggio dei Pini strada 54, 09012 Capoterra(CA), ItalyAbstract. The SRT (Sardinia Radio Telescope) is a general purpose, fully steerable, active surface equipped, 64 meters antenna,which is in an advanced construction state near Cagliari (Sardinia - Italy). It will be an antenna which could improve a lot theperformances of the EVN network, particularly at frequencies higher than 22 GHz.The main antenna geometry consist of a shaped reflector syste m pair, based on the classical parabola-ellipse Gregorian config-uration. It is designed to be able to operate with a good efficiency in a frequency range from 300 MHz up to 100 GHz. Thisfrequency range, is divided in two parts which define also two antenna operational modes, one up to 22 GHz with a minimalamount of accessory instrumentation, and the other up to 100 GHz with a full complement of instrumentation.The goal is to make it possible to build a telescope operable up to 22 GHz, and then upgrade it at a future date to operate atfrequencies up to 100 GHz.In order to get these goals, the SRT Metrology group is studying and developing different types of strategies, instrumentation,and techniques for measuring and reducing the various components of pointing and efficiency errors, taking advantage also fromexperiences developed in other radio telescopes, like GBT (Green Bank Telescope, USA), LMT (Large Millimiter Telescope,MEX), and IRAM (Institut de Radio Astronomie Millimetrique, Fr).Many of those system will be installed and tested at the 32 meters radio-telescope in Medicina (Bologna), before of theirimple-mentation on SRT.