Ion acoustic waves on the forward branch of the dispersion relation (also known as electrostatic ion cyclotron waves, ESICW, particularly when the frequency is close to an ion gyrofrequency) have been studied at angles from 40 degrees to 90 degrees , with a constant magnetic field in a relatively homogeneous plasma. Waves on the ion Bernstein backward wave branch were not detected. The wave vectors and damping coefficients have been deduced from interferograms and compared with theory, showing good agreement.