The polarization of electron‐cyclotron emission at the second harmonic (&ohgr;=2&ohgr;ce) has been measured both without and with a microwave absorber installed within view of the receiver to reduce wall reflection. Whereas without the absorber the radiation is dominantly unpolarized, with the absorber installed the radiation is significantly polarized, and the extraordinary mode intensity is typically three times the ordinary mode intensity. This indicates that wall reflections significantly depolarize the received radiation. Right‐hand‐cutoff effects are also observed and electron temperature is inferred from the emission from optically thin plasmas.