I have a pair of 433 MHz transmitter and receiver:

Transmitter is connected to Arduino pro mino, receiver to Arduino uno r3.

Output of receiver on serial looks like that(it doest change much):

Basicly I am getting either 75x or zero regardless of transmitter is on or off.

in > upper
756
in > upper
758
0
0
 0
in > upper
758
0
in > upper
757
in > upper

Transmitter code:

#define rfTransmitPin 4  
#define ledPin 6

void setup()
{
    pinMode(rfTransmitPin, OUTPUT);     
    pinMode(ledPin, OUTPUT);    
}

void loop()
{
    for(;;)
    {
         digitalWrite(rfTransmitPin, HIGH);     //Transmit a HIGH signal
         analogWrite(ledPin, 255);              //Turn the LED on
         delay(500);                            //Wait for 1 second
 
         digitalWrite(rfTransmitPin,LOW);       //Transmit a LOW signal
         analogWrite(ledPin, 0);                //Turn the LED off
         delay(500);                            //Variable delay
    }
}

Receiver code:

const unsigned int upperThreshold = 70;  //upper threshold value
const unsigned int lowerThreshold = 0;  //lower threshold value
const int ledPin = 13;

#define ReceiverPin  A0

void setup() 
{
    Serial.begin(19200);

    pinMode(ledPin, OUTPUT);

    DiodeTest();
}



void loop() 
{
   int data = analogRead(ReceiverPin);
   delay(50);
   
   if(data>upperThreshold)
   {
       digitalWrite(ledPin, LOW);   //If a LOW signal is received, turn LED OFF
       Serial.println("in > upper");
   }

   if(data<lowerThreshold)
   {
       digitalWrite(ledPin, HIGH);   //If a HIGH signal is received, turn LED ON
       Serial.println("in < lower" );
   }
   
   Serial.println(data);
}