We present an open source Software Defined Radio (SDR) receiver toolkit that is able to decode OFDM frames of IEEE 802.11a/g/p WiFi in real time. It is the first for GNURadio that supports channel bandwidths of up to 20MHz. The toolkit comprises the physical layer, decoding of MAC frames, and extracting the payload of IEEE 802.11a/g/p frames. It is further possible to access and visualize the data in every step of the decoding process in numerous ways. As an example demonstration, the impact of moving antennas and changing settings can be displayed live in time and frequency domain. Lastly, the decoded frames can be fed to Wireshark and/or received on a Linux network interface. Our receiver toolkit has been well received by the community and is already serving as the basis of further research.