50‐MHz echoes from equatorial spread‐F were observed on several nights by both the Jicamarca Radio Observatory (JRO) in Peru and the Cornell University Portable Radar Interferometer (CUPRI) in Alcântara, Brazil. Although little detailed correlation is expected between sites separated by such large distances, the night of October 17, 1994 shows some remarkable similarities between Peru and Brazil. On this night spread‐F commenced at both Jicamarca and Alcântara as thin bottomside layers situated near 320 km altitude at nearly the same local times. Later, major plumes erupted that reached to over 1000 km altitude at both sites. Since plumes normally drift west to east, these are obviously not the same structures but the similarities indicate that conditions for spawning them must have been coincidentally very similar on this night. The next two nights which produced plumes over Bra...

Incoherent scatter autocorrelation function measurements are difficult to make in the F región at Jicamarca because of very strong clutter contamination by coherent echoes from unstable plasma waves in the -B-region electrojet that are aligned with the magnetic field. We have developed a more effective way to deal with this clutter that improves the quality of the temperature (and composition when light ions are present) data. Other coherent echoes (much weaker than electrojet echoes but stronger than incoherent scatter) are also received through the antenna sidelobes from fieldaligned irregularities in the 140-170 km altitude range during daytime. These latter echoes have a very narrow bandwidth, and so it is easy to measure their Doppler shift and obtain the vertical plasma drift velocity, which is proportional to the zonal electric field.