The dynamic structure factors S ( q ,ω) of an ideal percolating network, the three-dimensional (3 d ) dilute Heisenberg antiferromagnet RbMn 0.4 Mg 0.6 F 3 , obtained from high resoluton (Δ E = 17.5 µeV) inelastic neutron scattering (INS) experiments are analyzed for the first time within the framework of the single-length-scaling postulate (SLSP). The analysis confirms the validity of the SLSP and is also used to extract the values of the key exponents governing the spin dynamics, the dynamic exponent (
zAF=Df/d~AF) being 2.5 ±0.1 and the spectral dimension
d~AF for antiferromagnetic (AFM) fractons taking a value of unity.