This project describes an Arduino-based FM transmission using the KT0803K Digital Stereo FM Transmitter Radio-Station-on-a-Chip. The KT0803K device is designed to process high fidelity stereo audio signal and transmit modulated FM signal over a short range. It features an on-board 20-bit audio ADC and supports standard I2C interface for frequency setting and power control
the range of this module without antenna around 40cm , you can connect an external antenna to increase the range of transmitter .
This module based on KT0803K Monolithic Digital Stereo FM Transmitter Radio-Station-on-a-Chip , designed to operate from 76-108 MHZ
the Full Data sheet for KT0803K here