Several countries in the world are undertaking an immensely challenging task: successfully perform the so-called "analogical blackout" of television. In Latin America in particular, the chosen transmission scheme is, in most cases, ISDB-T (the Japanese standard, later adapted by Brazil). Key to the success of this blackout is a thorough understanding of the technology of choice. The present paper intends to be a contribution to this understanding: an open, free and software-based ISDB-T 1-segment receiver. Such receiver may for instance be used to evaluate improvements to the standard (or different algorithms for the receivers), or even be used as a measurement tool (since one has access to the whole receiving chain). In addition to presenting our implementation, we discuss the technology that enables the software-based receiver: Software Defined Radio, and in particular the software framework GNU Radio.