A set of rotary joint components comprises a stationary part and a rotatable part, rotatable against each other. The stationary part has a stationary base with means for holding a stationary carrier into a circular-shaped form. The stationary carrier holds at least a stationary transmitter coupler of a contactless data link, such as a strip line. The stationary carrier is made of sheet metal or plastic material, and therefore can easily be prepared on a plane work bench before it is bent to a ring shape.