Apparatus for evaluating a communication between a first node (14, A, STA) and a second node (16, B, AP) of a radio communication system, comprising: an apparatus for generating a signal including an evaluation basis for the evaluation of the communication between the first node (14, A, STA) and the second node (16, B, AP) of the radio communication system based on a first version (22, L STA → monitor) of a radio signal (24, L STA → monitor, L STA → AP) transmitted from the first node (14, A, STA) to the second node (16, B, AP) received by a passive node that is to be positioned within the range of the first node, which differs from a second version actually received at the second node due to a positional deviation of the passive node from the second node, and means for performing the evaluation of the communication between the first and second nodes based on the signal; wherein the apparatus for generating the signal comprises means (30, 62) for detecting deviations of the first version of the radio signal from the second version of the radio signal received from the second node (16, B, AP); and means for generating the signal based on the deviations and wherein the means (30, 62) for detecting is configured to detect, without access to the transmitted radio signal and the version actually received at the second node, the deviations of the first version of the radio signal from the second version of the radio signal received by the second node (16, B, AP), namely by detecting packets missing in the first version compared to the second version by detecting omissions in sequence numbers in a sequence of packets in the first version and/or by detecting packets missing in the second version compared to the first version, which do not use sequence numbers, by checking a logical packet sequence for a protocol rule violation, wherein the means for generating is configured to obtain the signal containing the evaluation basis by modifying the first version of the radio signal based on the deviations and/or by providing the same with additional information concerning the deviations, so that the evaluation based on the signal is closer to that which would have been obtained based on the second version 26 received from the second node (16, B, AP). an apparatus for generating a signal including an evaluation basis for the evaluation of the communication between the first node (14, A, STA) and the second node (16, B, AP) of the radio communication system based on a first version (22, L STA → monitor) of a radio signal (24, L STA → monitor, L STA → AP) transmitted from the first node (14, A, STA) to the second node (16, B, AP) received by a passive node that is to be positioned within the range of the first node, which differs from a second version actually received at the second node due to a positional deviation of the passive node from the second node, and means for performing the evaluation of the communication between the first and second nodes based on the signal; wherein the apparatus for generating the signal comprises means (30, 62) for detecting deviations of the first version of the radio signal from the second version of the radio signal received from the second node (16, B, AP); and means for generating the signal based on the deviations and means (30, 62) for detecting deviations of the first version of the radio signal from the second version of the radio signal received from the second node (16, B, AP); and means for generating the signal based on the deviations wherein the means (30, 62) for detecting is configured to detect, without access to the transmitted radio signal and the version actually received at the second node, the deviations of the first version of the radio signal from the second version of the radio signal received by the second node (16, B, AP), namely by detecting packets missing in the first version compared to the second version by detecting omissions in sequence numbers in a sequence of packets in the first version and/or by detecting packets missing in the second version compared to the first version, which do not use sequence numbers, by checking a logical packet sequence for a protocol rule violation, by detecting packets missing in the first version compared to the second version by detecting omissions in sequence numbers in a sequence of packets in the first version and/or by detecting packets missing in the second version compared to the first version, which do not use sequence numbers, by checking a logical packet sequence for a protocol rule violation, wherein the means for generating is configured to obtain the signal containing the evaluation basis by modifying the first version of the radio signal based on the deviations and/or by providing the same with additional information concerning the deviations, so that the evaluation based on the signal is closer to that which would have been obtained based on the second version 26 received from the second node (16, B, AP).