I have a small FM transmitter that plugs into the car's cigarette lighter and a pen drive with the music to be transmitted to the FM radio. Its range is small, on the order of 4 to 5 meters. I would like to extend this range. How do I do?
The big problem with these transmitters is that they use dedicated low power integrated circuits that already generate signals for the antenna. In addition, they are SMD ICs that take up very little space on the device. One could think of an RF amplifier step connected to the antenna, but its placement in the circuit is problematic as there is little space and always the danger of generating more noise than signal. A stage with a 2N2222 could be used with increasing range to about 30 m, but it is difficult to implement. Ideally, mount a transmitter with higher power, starting from a complete circuit. On our site we have some small FM transmitters with ranges up to 200 m but that need audio signals in modulation.
