The invention relates to a mobile radio transmission unit for transferring data to a control and/or signal processing unit. According to the invention, provision is made for a mobile radio transmission unit for transferring data to a control or a signal processing unit, comprising a sensor arrangement for determining at least one component of a surrounding magnetic field. The sensor arrangement is connected to a monitoring entity which, from the at least one component, ascertains a variable that characterizes the surrounding magnetic field and prevents a transmission by an antenna of the radio transmission unit if the characteristic variable is below a threshold value.