I have these Arduino transmitters and receivers.This is how they look like

They are very common. I am just trying to transmit a "Hello" Message using this code.

#include <RH_ASK.h>
#include <SPI.h> // Not actually used but needed to compile

RH_ASK driver;
// RH_ASK driver(2000, 4, 5, 0); // ESP8266 or ESP32: do not use pin 11 or 2
// RH_ASK driver(2000, 3, 4, 0); // ATTiny, RX on D3 (pin 2 on attiny85) TX on D4 (pin 3 on attiny85), 

void setup()
    Serial.begin(9600);   // Debugging only
    if (!driver.init())
         Serial.println("init failed");

void loop()
    const char *msg = "hello";

    driver.send((uint8_t *)msg, strlen(msg));

But they have to be received from the receiver module using another set of codes which I have done it.

But my question is, is it possible to receive the transmitted message with one of RTL-SDR's INSTEAD of using the receiver module? If so, How to do it? My RTL-SDR:

  • yes, it is possible ... use a PC or a Mac ... run an audio recording program such as Audacity to see the waveform
    – jsotola
    Jul 22, 2019 at 3:47
  • @jsotola Ah I see, then how do I decode the audio into a string?
    – Physics
    Jul 22, 2019 at 3:54
  • i saw an article on the web once ... i think that it read the data from a weather station.... google sdr decoding weather station
    – jsotola
    Jul 22, 2019 at 3:58
  • Found it thanks, i will just put the link here for anyone interested: rtl-sdr.com/tag/weather-station
    – Physics
    Jul 22, 2019 at 4:02

1 Answer 1


In general you can use RTL-SDR to decode any AM and FM modulated signals (+some digital modulations) that lie within the frequency range form roughly 50MHz to about 1GHz. So 433MHz is confortably within that range.

There are many projects on GitHub that leverage the RTL-SDRs ability to decote 433MHz OOK modulated signals like:

Which comes with a ton of decoders for various appliances.

Which will give you the demodulated raw output for you to decode the bits yourself.

I'm sure you will find more but those are in my opinion the most noteworthy for the 433MHz OOK space.

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