Source characteristics of nonducted dawn-sector magnetospheric ELF/VLF chorus emissions are deduced from in situ chorus wave properties measured with the POLAR/PWI six-channel wideband wave receiver and applied as constraints to a simple chorus emission and propagation model. The model accounts for wave/particle resonance at the source and employs a multi-frequency ray tracing technique to estimate wave refraction and dispersion from source to receiver in order to accurately reproduce the observed frequency-time (f-t) spectral form and wave normal angle θp at the spacecraft, for some optimal combination of source L shell, magnetic latitude λs, and emission wave normal angle θs determined by iteration. The best-fit match for numerous chorus emissions observed over a dawn-sector orbit pass covering 3.5 0) produced on the opposite side of the equator with respect to the receiver, and chorus fallers (df/dt 0, since the spatial wave growth profile increases in the direction towards the receiver and in fact reaches maximum intensity at or just beyond the magnetic equator, the waves appear to emanate from the equator itself. A symmetric ensemble of such chorus emissions thus produces waves which appear to propagate universally away from the magnetic equator, in accord with the observations of LeDocq et al. <1998>.