The characteristics of the lower hybrid wave in an octopole tokamak, HYBTOK-I, are investigated with a T-shaped alumina-loaded wire antenna well analysed both theoretically and experimentally, and with an on-line matching system reducing the reflected power. The ray trajectories derived by a full electromagnetic treatment are obtained for a tokamak plasma with non-circular cross-section. Mode conversion from slow to fast waves ensures the presence of a surface wave with weak longitudinal retardation. The effect of the plasma shaping on the wave trajectory is discussed. The rotational transform of the wave trajectory is checked with an RF probe. The resonant decay daughter wave energy penetrates well inside the plasma.