  One or more radio-frequency jumps are usually necessary for realizing a >=
100 AMeV/u proton or ion driver linac. Typically, such jumps happen in the
range of \b{eta} = 0.2-0.6 between the resonator structures fitting to this
\b{eta}-range, e.g. DTL, HWR, CCL or elliptical cavities. We propose to perform
the first frequency jump already at low energies (\b{eta} <= 0.1) between two
RFQ accelerators, which can bring some unique advantages. First studies have
been performed and the results proved that this idea is feasible and promising.
Many efforts have been and are being made to address the most critical issue
for the jumps i.e. the beam matching at the transition.
