Book excerpt: A joint United States - Brazil experiment was conducted near the geomagnetic equator to confirm the theoretically predicted strong dependence of the ionospheric reflection properties on the azimuthal direction of wave propagation. Skywave delays, reflection coefficients, and polarization ellipses were measured at different frequencies, ranges, and azimuths. The results were compared with full-wave computer calculations for several ionospheric models. A series of high resolution waveforms showing the sunrise transition from night- to daytime conditions is included.