For legally distribute in USA and Canada market, RF remote control transmitters must be certified by FCC approved labs and get a FCC ID, the testing procedure can be carried either by manufacturer in China or by seller in USA.
The major remote control parameter that FCC require is simply limit RF transmission power in given time frame, which means two aspects, the transmitter’s radiation strength as well as transmitter’s radiation time span.
When using low cost while mainstream SAW-based remote control transmitters, the 2nd and above harmonics is difficult to be kept under required level, so this is the reason why most low cost SAW-based remote control transmitters will fail in harmonics test.
While at Solidremote, we have now designed a solution for customers who need FCC certification, the solution is by using latest generation Si4010 chip and carefully PCB layout, in this way, we can limit 2nd and above harmonics as well as achieve the designed radiation power at designed transmission frequency.
For comparision, the following photo is taken using spectrum analyzer at 868Mhz center frequency, which is the 2nd harmonics of 433Mhz, the left is SAW-based remote control transmitter while the right is Si4010 based remote control transmitter using carefully designed PCB loop antenna.
As you can see, the 2nd harmonics is still very strong for SAW-based transmitter, while is much lower for Si4010 based transmitter using loop antenna, which means the Si4010 based remote transmitter can pass FCC ID harmonics certification.