In this paper we propose what we believe to be a novel method for monitoring chromatic dispersion (CD). We use radio-frequency (RF) power monitoring and Q-factor monitoring. We use a method for capturing opened eye diagrams with high-speed electro-optical sampling. This allows the calculation of the Q factor, here used to signal the correct CD. Simulation results show that with this method it is possible to have monitoring windows up to 2040 ps/nm at 40 Gbits/s, using the return-to-zero (RZ) and carrier-suppressed return-to-zero (CSRZ) modulation formats. For that to happen we just need to increase the number of iterations and the monitoring window of the variable dispersion compensator (VDC) algorithm explained further. With this method we obtain a high monitoring sensitivity of 0.3363 dB/(ps/nm).