I bought 2 cheap 433Mhz receiver modules from aliexpress for comparison. One named RBX6 :

and one noname set:

This is my test setup – wire antena and 3xAAA cells supplying 4.5V power:

and these are their output waveforms on scope (the blue one is RBX6):

• noise with some signal starting at the end:
  
• random signal from outside
  
• my remote 5 cm from receivers
  

Make a conclusion on your own.