This IEEE EFTF/IFC 2017 paper by Handel discusses quantum theory of 1/f frequency fluctuations, demonstrating macroscopic quantum interference present in fundamental 1/f noise measured since 1925. The research presents historical and theoretical analysis showing that quantum mechanical interference effects manifest in 1/f frequency fluctuations observed in early precision oscillator measurements, establishing that quantum 1/f noise has been unknowingly measured for nearly a century and represents a fundamental quantum phenomenon with macroscopic consequences.