Detecting a leak of an OFDM signal from an HFC network, where the HFC network extends over a network area. The OFDM signal includes a first continuous pilot subcarrier having a first harmonic. The first harmonic is defined by a pre-determined first frequency. The method or apparatus comprises the steps of or means for: (a) moving a leakage detector through the network area; (b) tuning the leakage detector to receive the first harmonic of the OFDM signal, based on the pre-determined first frequency of the first harmonic; (c) with the leakage detector, receiving over-the-air, at a received first frequency, the first harmonic of the OFDM signal leaked from the HFC network; and (d) with the leakage detector, detecting the first harmonic received in step (c), whereby the leak of the OFDM signal is detected based on the detection of the first harmonic.