  Because of the bulk gap, low energy physics in the quantum Hall effect is
confined to the edges of the 2D electron liquid. The velocities of edge modes
are key parameters of edge physics. They were determined in several quantum
Hall systems from time-resolved measurements and high-frequency ac transport.
We propose a way to extract edge velocities from dc transport in a point
contact geometry defined by narrow gates. The width of the gates assumes two
different sizes at small and large distances from the point contact. The
Coulomb interaction across the gates depends on the gate width and affects the
conductance of the contact. The conductance exhibits two different temperature
dependencies at high and low temperatures. The transition between the two
regimes is determined by the edge velocity. An interesting feature of the
low-temperature I-V curve is current oscillations as a function of the voltage.
The oscillations emerge due to charge reflection from the interface of the
regions defined by the narrow and wide sections of the gates.
