5Pcs 433MHz RF Wireless Transmitter and Receiver Module Kit for Arduino/ARM/MCU, and for Raspberry pi

Personally, I'm very happy with these. I realize there's some negative reviews regarding having to add the antenna but, honestly, the product pictures do not show an antenna. The cool thing is you can experiment with various wire thickness, and length of antennas on the transmitter. For example, I first used straight, insulated 22AWG jumper wire and just set the DuPont connector in the antenna hole without soldering it. I was able to get a 25' transmission distance. After soldering it, it increased to 40'. I replaced it and soldered a 26AWG conductor with 7 turns and was able to transmit to my neighbors yard through one wall at 100'. I think it's smart they DIDN'T include the antenna so the user can determine the range they need. But that's me!

The transmitters were hardly putting out any RF; with a spectrum analyzer I could not get a reading unless the antenna was right next to the proper antenna soldered onto the transmitter. Per the schematic diagram, there should be a 3-turn inductor attached to but board above the 8-turn inductor. With this inductor missing, there cannot be any output to the antenna. I wound one on my own with some enameled wire (second photo shows the 'fix') and the transmitters worked as advertised. Shop around carefully, this particular product from this vendor is garbage!

Better off waiting a couple extra days for a better quality component from a different seller. These worked, but are so noisy I am not going to spend hours to days to tune them.

The transmitter modules are missing one of the two coils required for it to work. Buy from a listing that shows both coils present on the transmitter modules.

These work well, but you should consider the set with the extra 4 pins on the reveiver since you can easily add an external antenna