1. An OFDM signal transmission system comprising: a first reception block equipped with a first reception section that receives a first transmission signal sent from a transmission station that transmits a modulated signal modulated according to an OFDM modulation system using a first frequency band, a tuning section that tunes the first received signal, a first demodulation section that demodulates the first received signal and an output section; and a second reception block equipped with a second reception section capable of receiving a second transmission signal sent from a transmission/reception station that carries out reception using a second frequency band which is different from the first frequency band and a second demodulation section that demodulates the second received signal, wherein the identification information of transmission/reception station included in the second received signal and/or information to perform at least one of tuning or demodulation of said first transmission signal is received, transmission information to perform at least one of tuning or demodulation of the first transmission signal is obtained, at least one of tuning or demodulation of the first received signal is performed at said first demodulation section.