Detailed first estimates are presented of angular broadening in the ou
ter heliosphere due to scattering of radio waves by density irregulari
ties. The application is to the 2-3 kHz radiation observed by Voyager.
Two plausible turbulence models, which account very well for scatteri
ng within 1 AU, are extrapolated beyond 10 AU. Both models predict sig
nificant angular broadening in the outer heliosphere, accounting semiq
uantitatively alone for the source sizes inferred from roll modulation
data. Predictions are presented for radial variations in the apparent
source size if scattering is important. Comparisons with available da
ta argue that scattering is important (and indeed is the dominant cont
ributor to the apparent source size) and that the radiation source is
located in the outer heliosphere. Other evidence that scattering is im
portant, such as the fluctuations in apparent source direction and int
ensity, are also identified. The effects of scattering should be inclu
ded in future analyses of the 2-3 kHz emissions.