Interfacing the RS232 to TTL with Raspberry pi pico using arduinoIDE

[sterretje]

@vsdevatkal2001

here I am pasting the snippet where I am reading the data

Please post complete code. Or a representative example that demonstrates the issue.

@vsdevatkal2001

      if (data == stop_delimiter && index >= RadarBuffLength) {
        break;
      }

So even if you have found the stop-delimiter, you don't break.

What is the sender?

Note: you might find a suitable approach to serial reading in Robin's updated serial input basics tutorial