Sorry I did not understand about the height. I have removed one line now. Yes the height is sent relative to 0 feet which I set with a button when the TX is on the ground. Then the TX is in a model glider and as it asends the data is sent to the RX and displayed on the Oled but I have to watch the plane so i need an indication with the buzzer when I rech 100 meters and so on up to 800 meters which is the max I can fly according to law. The 800 meter buzzer then has to be constant and not intermittent. I hope this shows what i am trying to achieve.