JVT:
I'm working on an RF transmitter and receiver project using the cheap 433mHz transmitters and receivers and RcSwitch library. Currently, the receiver works at upto 7 metres with a masonry wall obstruction. But beyond the 7 metres, it looses communication. Please can someone advice me on which transmitter to use to achieve at least 20 metres regardless of obstructions. Thanks. The transmitter and receiver are attached below.
Transmitters are limited by law to a certain RF output. Higher voltage doesn't change this. There may be output steps available in the programming of the transmitter, investigate what you are setting it to. The receiver is where you should pay attention. Better antennas, lower noise receiver, gain antenna rather than a bit of wire.
Actually better antennas on both will help.
Paul