Getting unexpected results

Ok, so I am really new to this, I have read the introduction and hope I have posted correctly, if not please advise so I can improve,.

I have bought a board and I am following the tutorials on line. The following code should simply replay the character I have entered i.e. type "a" and it plays back "a". Seems straightforward, but my board (UNO) is doing that but then adding two extra blank lines - like this...

16:32:05.801 -> a
16:32:05.801 ->
16:32:05.801 ->
16:35:10.242 -> 1
16:35:10.242 ->
16:35:10.242 ->

The code is as follows

void setup() {

void loop() {
  char rx_byte;

  if (Serial.available() > 0) {
    rx_byte =;

I would appreciate any guidance to help, I have been messing with this for about 3 hours today. Fully accept it might be something mind numbingly simple, and I am just misunderstanding.

Thanks to anyone who could help.

Check the line end character in the box at the bottom of the serial monitor box. Set it to no line ending.

Thanks, solved that bit.
Really appreciate your help, I fully expect to be back on here as I learn more about what I don't know.
Thanks again.

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