High SWR or Unable to Tune

In case the ATAS-120A does not manage to tune or complains about "High SWR" the first and foremost recommendation is to ensure that the antenna is grounded properly. Usually antennas are connected using the base mount to the chassis of a car such that the chassis becomes the ground plane. In case the ATAS-120A antenna is used without a car mount, then proper grounding must be ensured.

For best performance, ensure that the grounding of the radio is connected to the ground of the antenna (the outer, encompassing ring around the center pin of the antenna).