Review on Wireless 433MHz RF Module Receiver With 4 Channel Output – QIACHIP RX480E (20 Pcs) by Vivian Eker

I bought these modules to upgrade a checkpoint box for the Santa Monica Sports Car Club. I bought 3 sets so I could experiment with different antennas. I had best results with a Moxon antenna on the transmit side and the coil antenna (supplied with the kit) on the receiver. I tried connecting a rubber wand antenna to the receiver and it quit working. I could not repair it. On the second chip, I used the little coil antenna and it works surprisingly well even completely enclosed in an aluminum box. I really like the fact that the transmitter works with more than 5 volts. I am using a 12 volt laptop battery with a resistor dropping the voltage to 9.25 for long life. I connected the chosen receiver output pin to the base of 2N3904 NPN transistor through a 10K ohm resistor. The emitter goes through a 470 ohm resistor to ground. The collector goes through a cable to a pin in the digital clock that expects a negative trigger. So, very few extra parts! Both chips get pretty hot, so I used perforated covers on the enclosures.I just tested the system in a Costco parking lot. The transmitter is in the checkpoint box connected to a pneumatic switch connected to a rubber hose across the driveway. As cars drive over it, the signal goes to the receiver which is connected to very precise Alfa Clubman digital clock in my car. I kept trying longer distances until I reached 200 feet. At that distance, it worked 29 times out of 30 cars over the hose. Since we usually have the checkpoint box about 100 feet in front of the timing car, I am very happy with the result and can time cars to the 100th of a minute. I will be using this equipment to time rally cars on tomorrow’s First Friday Niter Rally.