Small angle neutron scattering has been used to measure the radius of gyration of deuterated linear polystyrene at dilute concentration contained in a polystyrene network with different crosslink densities. At each crosslink density, four samples with different linear chain concentrations (less than the overlap concentration) were made. The lower crosslink density samples (N-c>180) remained single phase, while higher crosslink density samples showed evidence of phase separation. Zimm plots were made for all samples which were single phase, and the second virial coefficient was obtained as a function of crosslink density. It was found that the second virial coefficient decreased with increasing crosslink density. Single chain form factors were obtained by extrapolating the scattering data to zero concentration of the linear chain for the single phase samples. A modified Debye equation was used to fit the zero concentration extrapolated scattering data over the entire experimental q range to obtain the radius of gyration, R-g, for the linear chain. It was found that R-g was a function of the crosslink density. When the crosslink density was low (N-c > N-l), R-g did not change appreciably and had a value nearly the same as in the melt. For higher cross-link density samples (N-c < N-l), R-g was found to decrease with increasing crosslink density and the scaling relation R-g(-1) similar to N-c(-1) was observed. Chain segregation was observed for the highest crosslink density samples. The dependence of R-g, on crosslink density can be qualitatively explained using a theory for the conformation of polymer chain in a random media. For the phase separated samples, a two correlation length theory was used to fit the scattering data.