Trying to obtain phase angle using AD 8302 phase detector chip.

I am trying to use the AD 8302 phase detector chip to obtain phase angle between antenna’s receiving a RF signal due to the vertical separation of the antennas. I want to use the phase angle to calculate the distance from the transmitter to the receiving antennas that are placed on an upright wooden platform. These antennas have a vertical separation of 5 ft from each other.

The transmitter operates on 433 MHz and its the generic transmitter/ receiver pair. The phase detector gives me phase output in terms of Volts that has a range of 30mV to 1.8 V. In the data sheet this range represents 180 degrees to 0 degrees. The outputs from the phase detector chip go into the arduino and that is how I make the calculations for the distance as well as the angle.

I have calculated antenna lengths (reception antenna’s) for Quarter Wavelength.

These are the relevant links:


This is to calculate antenna length using a piece of wire:

I am not able to obtain the correct phase angle needed to calculate the distance from the transmitter to the antennas.

PIC_1 is the structure and PIC_2 is the transmitter.

This is the code for the transmitter:

#define rfTransmitPin 12  //RF Transmitter pin = digital pin 12
#define ledPin 13        //Onboard LED = digital pin 13

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

void loop(){
  //for(int i=4000; i>5; i=i/800){
    digitalWrite(rfTransmitPin, HIGH);     //Transmit a HIGH signal
    digitalWrite(ledPin, HIGH);            //Turn the LED on
    //delay(2000);                           //Wait for 1 second
   // digitalWrite(rfTransmitPin,LOW);      //Transmit a LOW signal
   // digitalWrite(ledPin, LOW);            //Turn the LED off
   // delay(i);                            //Variable delay
 // }

This is the code for the Receiver:

//#define rfReceivePin 8  //RF Receiver pin = Analog pin 0
#define vmag A1 
#define vphs A0
#define ledPin 13        //Onboard LED = digital pin 13
//int vphs = 0;
//int vmag = 1;
unsigned int data = 0;   // variable used to store received data
unsigned int DATA = 0; 
unsigned int data1 = 0;
unsigned int DATA1 = 0;

const unsigned int upperThreshold = 70;  //upper threshold value
const unsigned int lowerThreshold = 50;  //lower threshold value

String angle="Angle:";
String mag="Vmag:";
String dis="Distance";

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

void loop(){
  data = analogRead(vphs);    //listen for data on Analog pin 0
  data1 = analogRead(vmag);
 /* if(data>upperThreshold){
    digitalWrite(ledPin, LOW);   //If a LOW signal is received, turn LED OFF
    digitalWrite(ledPin, HIGH);   //If a HIGH signal is received, turn LED ON


Please edit your post to add code tags. See the "How to use this forum" post.

I have edited my post.

Are you supplying enough RF power to the antennas to enable the chip to determine the phase difference? Is your transmitter sending data or sending an FM signal?

What voltage are you actually getting form the chip for the phase difference?