Telescopic radio aerial for motor vehicles - has variable tuning signal generator coupled to setting device adjusting aerial length according to signal magnitude

The longitudinal adjustment of a radio telescopic aerial is carried out by a device containing a signal generator responsive to the tuning frequency. It is connected to an adjuster for the telescopic aerial length in dependence on the signal strength. Preferably a variable resistor is used as the signal generator, which is mechanically connected to the radio receiver tuner. Alternately a capacitor connected in the same manner may be used for this purpose. In this way the increase of signal noise, inherent in the radio receiver amplification of low voltage aerial signals, can be avoided, particularly in the ultra-short wave band.