The HP / Agilent 11794-60028 Preselector Power Supply. All HP / Agilent 11974 series mixers connect to this stand alone power supply with a convenient 6-foot cable (part number 5061-5458). Use this same power supply with any 11974 series preselected mixer. HP / Agilent 11974 series preselected millimeter mixers are compatible with HP / Agilent’s 8566B, 8560 series and E4407B of rugged portables, 70000 Series modular spectrum analyzers and the PSA Series.