  We study selected properties of Solar Energetic Particle (SEP) events as
inferred from their associated radio emissions. We used a catalogue of 115 SEP
events that consists of entries of proton intensity enhancements at one AU,
with complete coverage over solar cycle 23, based on high-energy (~68 MeV)
protons from SOHO/ERNE and we calculated the proton release time at the Sun
using velocity dispersion analysis (VDA). After an initial rejection of cases
with unrealistic VDA path lengths, we assembled composite radio spectra for the
remaining events using data from ground-based and space-borne
radio-spectrographs. For every event we registered the associated radio
emissions and we divided the events in groups according to their associated
radio emissions. The proton release was found to be most often accompanied by
both type III and II radio bursts, but a good association percentage was also
registered in cases accompanied by type IIIs only. The worst association was
found for the cases with type II only association. These radio association
percentages support the idea that both flare- and shock-resident particle
release processes are observed in high-energy proton events. In cases of type
III-associated events we extended our study to the timings between the type III
radio emission, the proton release, and the electron release as inferred from
VDA based on Wind/3DP 20-646 keV data. Typically, the protons are released
after the start of the associated type III bursts and simultaneously or before
the release of energetic electrons. For the cases with type II radio
association we found that the distribution of the proton release heights had a
maximum at ~2.5 Rs. Most (69%) of the flares associated to our SEP events were
located at the western hemisphere, with a peak within the well-connected region
of 50-60 deg western longitude.
