Actually, it is; essentially every tunable radio receiver built in the last 90 years or so is also a transmitter. The reason is the almost universally-used heterodyne circuitry that converts the received signal from various frequencies into a standard frequency that's fed into other circuitry, hardwired to maximize its performance at a single frequency, which demodulates the signal and turns it into analog or digital audio or video.

They're low-power transmitters, but still transmitters.