The detection of Alfvén cascades is of great importance for the development of advanced plasma scenarios with reversed magnetic shear on the JET tokamak, since they allow the determination of the minimum of the safety factor. X-mode reflectometry is particularly powerful for this diagnosis since both the time-frequency evolution and the radial localisation of these Alfvén Eigenmodes (AEs) can be simultaneously obtained. This paper reports on the first successful localised measurements of AEs achieved with the recently upgraded X-mode reflectometry diagnostic on JET.