Under specific circumstances, the v.l.f. receiver (400 Hz–10 kHz) aboard the Alouette I spacecraft has observed an interference signal originating with an electrical converter system. The chief characteristics of this signal are that it appears only in daylight operation and is spin modulated in such a manner that signal nulls appear when the spacecraft is oriented for minimum V × B effects. To explain these features, a mechanism was postulated which involves a coupling of the converter signals via the power-supply internal impedance and the solar-cell chain to the plasma environment and thus to the v.l.f. antenna, but requiring the asymmetry of the V × B sheaths for coupling. In order to test the validity of this theory, a simple satellite model was immersed in a low-density plasma, and operations under different space conditions were simulated. It was shown that the system design of the spacecraft could permit observation of such an interference signal under the required conditions.