How to get the RSSI in CC2500?

Hello everyone,

I want to design a system in which I can show the strength of received signal on computer screen. Basically Receiver would get the strength and send it via serial port to PC in which GUI is designed.

Now I have a portable transmitter which would transmit the packets of data every second. I am able to receive the packets at the receiver side. My question is how to get the signal strength so that I can know how far my transmitter is located?

I have tried to get the RSSI value every time controller receives the packets. But it gives the fixed value 250 with some fluctuations. Here is the code I am using at the receiver side. I am using eZ430-RF2500 module with the library codes of cc2500 provided by TI (sla325a)

----------------------------------------------------------------------------------

#include "include.h"
#include "msp430.h"


extern char paTable[];
extern char paTableLen;
extern void init_cc2500(void);
extern unsigned int convert_to_dec(unsigned int);
extern void init_uart(void);

char txBuffer[8];
char rxBuffer[8];
unsigned int i = 0,rssi,rssi_dec;


void main (void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT

  init_cc2500();
  init_uart();
 
  __bis_SR_register(LPM3_bits + GIE);
}

// The ISR assumes the interrupt came from GDO0. GDO0 fires indicating that
// CCxxxx received a packet

#pragma vector=PORT2_VECTOR
__interrupt void Port2_ISR(void)
{
  // if GDO fired
  if(TI_CC_GDO0_PxIFG & TI_CC_GDO0_PIN)
  {
    char len=7;                             
    
    if (RFReceivePacket(rxBuffer,&len))     // Fetch packet from CCxxxx
    {
          P1OUT ^= 0x01; 

          rssi = TI_CC_SPIReadStatus(TI_CCxxx0_RSSI);

          while(!(IFG2 & UCA0TXIFG));

          IFG2 &= ~UCA0TXIFG;
          UCA0TXBUF = rssi;
          P1OUT ^= 0x02;
         
    }
  }
   TI_CC_GDO0_PxIFG &= ~TI_CC_GDO0_PIN;      // After pkt RX, this flag is set.
       
}

----------------------------------------------------------

Thanks.