Abstract: The present invention provides a vehicle antenna system including a high frequency pickup with a loop antenna for detecting high frequency surface currents induced on the vehicle body by broadcast waves and concentratedly flowing on the marginal portions of the vehicle body, the loop antenna being longitudinally disposed in close proximity to a marginal portion of the vehicle body, the improvement including a switching diode on the loop antenna for changing the opening area thereof. Therefore, the loop antenna can stably receive waves through an increased range of bands independently of variations in power voltage.