  We have studied a clean finite-length line junction between interacting
counterpropagating single-branch fractional-quantum-Hall edge channels. Exact
solutions for low-lying excitations and transport properties are obtained when
the two edges belong to quantum Hall systems with different filling factors and
interact via the long-range Coulomb interaction. Charging effects due to the
coupling to external edge-channel leads are fully taken into account.
Conductances and power laws in the current-voltage characteristics of tunneling
are strongly affected by inter-edge correlations.
