A citizens band transmitter employing negative overall envelope feedback in the final RF stage obtains the feedback signal from a filter in the antenna coupling network which has a phase shift of 90 degrees or an odd multiple thereof at the radio frequency. A pair of detector diodes have their cathodes connected to opposite ends of filter and their anodes connected to a low pass filter to provide an envelope of the higher of the two voltages at either end of the filter in the coupling circuit in negative feedback to the modulating signal.