High power density ICRF launchers will be needed for ITER and, after the end of the 2004 campaigns on JET, an ITER-like ICRF launcher will be installed and tested in JET. The reference design coupling performance (dipole phasing) may be improved if the loss of heating efficiency for the launcher in toroidal monopole phasing is reduced. In older measurements of plasma energy content vs. input power at JET, practically no hydrogen minority heating was observed for monopole with the present A2 antennae, although the coupling resistance was better in monopole than in dipole. The unaccounted coupled power in monopole is likely deposited through parasitic absorption in the enhanced sheaths.