A probe experiment, consisting of radio links between a common 30-MHz transmitter located at Murmansk, Russia, and two receivers used as the imaging riometer (two-dimensional 64 multiple-beam antenna) located at Ny ¿lesund, Svalbard, and Tjornes, Iceland, was carried out to characterize wave scatter in the high-latitude ionosphere. They are nearly aligned with and perpendicular to the geomagnetic meridian, respectively. In experiments conducted in March--April 1994, the 30-MHz probe signals were identified at nighttime more frequently than during the day at both receiver stations during periods of increased geomagnetic activity near the path midpoints, indicating that a relationship between the propagation path and the location of the auroral oval controls signal identification. For the nighttime propagation paths within or crossing through the auroral oval, duty cycles of the probe signals were roughly correlated with increases in geomagnetic activity. Their arrival directions showed a spread with a dominant power on the low elevation and a normal distribution in azimuth. These results indicate that the probe signals are characterized as nonmeteoric auroral E scatter caused by irregular, large-scale profiles of electron density enhancements at the lower edge of the ionosphere. However, on 2 days of weak geomagnetic activity, strong probe signals with bursty behavior were identified by an extremely high duty cycle (~98%) for the nighttime meridian path only, and their arrival directions showed an isotropic spread in azimuth. Such nonmeteoric probe signals are characterized as coherent scatter caused by small-scale (~5 m) field-aligned irregularities in electron density in the E region ionosphere, related to sporadic E occurrence. ¿ 1999 American Geophysical Union