A system includes a first external mounted amplifier having a first low-noise amplifier coupled to a first antenna, a second EMA having a second LNA coupled to a second antenna, a first splitter coupled between the first antenna and the first LNA, a first phase shifter coupled to the first splitter, and a second mixer coupled to the first phase shifter. These diseases are characterized by aggregations of alpha-synuclein. Each rubber sleeve includes a first portion, which faces the side portion of the drum, and a second portion, which faces the bottom of the drum.