Abstract: The antenna for equipping a portable receiver comprises a metal plate and a metal box containing the receiver components and which is provided with a surface facing the metal plate, the metal box behaving in the manner of a virtual plate positioned half-way up the box.

Abstract: Mixer which has, in place of four conventional diodes, the collector - emitter spaces of transistors polarized to earth and supplied at their bases by the local oscillating signal across a coupling system and as a result giving performance levels like those obtained with diodes, but with a lower local oscillating power.

Abstract: The bias circuit of the base of an HF amplifier transistor, arranged in a common-emitter configuration, comprises an LF transistor likewise in a common-emitter configuration and two resistors respectively connecting the base of the LF transistor to its collector and to a point of fixed potential. The bias voltage varies more rapidly, as a function of temperature, than the voltage across the terminals of the reference diode formed by the base-emitter junction of the LF transistor. This permits a correct temperature compensation of the HF transistor in spite of the temperature differences between the junctions of the HF and LF transistors and of the thermal inertia of the thermal link between these two transistors.