A device and a method for detecting a spike during a magnetic resonance scan are provided. The device has a first receiver with a first signal connection for connecting a local coil and a second receiver with a second signal connection for connecting a reference antenna. The device is configured to compare a first signal received by the first receiver via the first signal connection with a second signal received by the second receiver via the second signal connection and, in the event of a predetermined deviation, to emit a warning signal.