I am trying to use nRF24L01 with antenna in my project, but when I do test with getting start from rf24 master is showing a serial monitor like in the picture abov e. What is the problem here?
Search in the code for the line
Serial.begin(###) where ### is a number representing the serial speed, also known as baud rate.
This number must match with the baud rate of your serial monitor, otherwise all you get is garbage.
BTW, this has nothing to do with nRF24, this is plain Arduino serial connection.