Coordinated measurements of equatorial spread-F conducted during July 1979 at the Kwajalein Atoll have yielded the first definitive space- and time coincident radar and rocket observations of small scale irregularities and large scale plasma depletions. The results have shown that: (a) During conditions of well-developed equatorial spread-F the most intense ''in sity'' irregularities occurred on the bottomside F-layer gradient. (b) Within a large scale topside F-layer depletion radar backscatter and ''in situ'' irregulatiry strengths maximized near the depletion's upper wall. (c) Ion composition within a topside depletion provided signatures of its bottomside source domain and estimates of average maximum vertical drift velocity. For long-lived depletions, it was found that molecular-ion signatures (NO+ and O2+) can be lost while bottomside levels of N+ can be maintained when [O+>?Ni≫[NO+>+[O2+>; and finally, (d) Large scale fluctuations of O+ accompanied by a near-constant level of NO+ and O2+ on the bottomside F-layer gradient suggests that neutral atmospheric turbulence is not a major source for bottomside ionospheric plasma irregularities and the accociated triggering of equatorial spread-F.