i have a tiny RF 433mHz project with my Raspberry Pi 3 Model B v1.2 and Arduino Pro mini.
My Raspberry works as a receiver and Pro mini as a transmitter.
I have wiried the popular RF receiver MX-RM-5V to my RPi's GPIO.
Receiver and transmitter modules have coiled antennas.
I used the GPIO 5V pin to supply my receiver and logic level converter.
I'm using logic level converter because the receiver works with 5V and GPIO with 3.3V logic.
The problem is that if i use the GPIO 5V pin to supply my RF receiver module the range drops to 10 cm.
When i supply my receiver module with external adapter @ 5V the range increases to 10 - 15 meters.
Raspberry has micro usb 2A adapter. The MX-RM-5V uses 11.50 mA.
Why the GPIO 5V pin can't supply the MX-RM-5V module ?
Is there some component on the raspberry's 5V rail between micro-usb and gpio 5v pin that limits the current ?
How much noise the Raspberry generates on its rails and what kind ? Can this be the problem ?