This paper presents the development of a set of calibration monocone antennas, each mounted on a small ground plane, designed for automotive range calibration. These antennas cover a frequency range from 70 MHz to 6 GHz using only four antennas, with the flexibility to extend to an even broader frequency spectrum. The wideband monocone antennas offer significant advantages for automotive facility calibration, as they closely resemble the wide-coverage antennas commonly used in vehicle communication systems, enabling full range calibration with a minimal number of antennas. To accurately derive performance data for the lowfrequency monocone antennas, scaled models were employed. These scaled models are highly precise replicas of their higherfrequency counterparts, enabling measurements that maintain critical parameters such as gain, directivity, and efficiency. The data obtained from scaled measurements can be effectively extrapolated to full-scale performance. The paper also discusses key design considerations and provides details on the scaled modeling approach, as well as the validation experiments conducted in a full-scale automotive measurement facility