A radio response system including a broadcast station, a satellite relay, a processing center, and a plurality of user terminals. Each user terminal has a broadcast receiver, a communications interface device, a controller and a data transmitter. The broadcast station broadcasts a program signal. The broadcast receiver receives the program signal. The communications interface device communicates the program signal to a user. The controller generates a user-data signal from identification information transmitted in connection with the program signal and/or timing, location and frequency information needed for identifying the program signal, and a user-input signal generated in response to the program signal. The data transmitter transmits the user-data signal at a carrier frequency as a transmitted-data signal. The satellite relays the user-data signal to the processing center.