The MAST Synthetic Aperture Microwave Imaging (SAMI) radiometer is an antenna array designed to image thermal microwave emission from MAST fusion plasmaaSAMl is now installed on MAST and preliminary data has been taken. This data clearly show the presence of electrostatic to electromagnetic mode conversion and the circumstances under which this mode conversion take place are strongly related to the pedestal density gradient and magnetic field. These quantities are valuable in understanding tokamak pedestal behaviour and are especially important to models of the Edge Localised Mode (ELM). This paper describes SAMIs design and construction, as well as fist signals showing the presence of mode conversion