  A new acousto-optic radio spectrometer has observed the 1 - 2 GHz radio
emission of solar flares with unprecedented sensitivity. The number of detected
decimeter type III bursts is greatly enhanced compared to observations by
conventional spectrometers observing only one frequency at the time. The
observations indicate a large number of electron beams propagating in dense
plasmas. For the first time, we report weak, reversed drifting type III bursts
at frequencies above simultaneous narrowband decimeter spikes. The type III
bursts are reliable signatures of electron beams propagating downward in the
corona, apparently away from the source of the spikes. The observations
contradict the most popular spike model that places the spike sources at the
footpoints of loops. Conspicuous also was an apparent bidirectional type U
burst forming a fish-like pattern. It occurs simultaneously with an intense
U-burst at 600-370 MHz observed in Tremsdorf. We suggest that it intermodulated
with strong terrestrial interference (cellular phones) causing a spurious
symmetric pattern in the spectrogram at 1.4 GHz. Symmetric features in the 1 -
2 GHz range, some already reported in the literature, therefore must be
considered with utmost caution.
