A coaxial RF test connector comprises an inner conductor and an outer conductor arranged coaxially to a center axis. The outer conductor comprises a groove for holding a circular shaped contact spring. The contact spring comprises a base and a plurality of arc-shaped contact fingers with gaps between the individual contact fingers extending from the base. The base has a larger radius than the contact fingers. The contact fingers have first contact section for contacting the outer conductor of an compatible coaxial connector in a direction radial to the center axis and a second contact section for capacitively coupling to a sidewall of the groove.