Measurements of the polarizing efficiency and transmittance of a new high-efficiency multichannel neutron polarizer are presented. The procedure of the measurements is given. The parameters of new Fe₃₀Co₆₈V₂/Ti₇₅Zr₂₅ supermirrors and a polarizer made of them are compared with old Fe₃₄Co₆₄V₂/Ti₆₀Zr₄₀ supermirrors and an old polarizer. We discuss how the polarizing efficiency of the coating was improved.