The microwave conductivity perpendicular to the linear chain direction in t
he presence of randomly distributed impurities is calculated within mean fi
eld theory for spin density waves. Interchain hopping is taken into account
and the effects of imperfect nesting are considered. Our results are direc
tly applicable to recent measurements on both (TMTSF)(2)PF6 and quenched (T
MTSF)(2)ClO4. The experimental data are well described by the theory in its
clean limit.