All of the potential Samsung TV codes and findings are contained within this thread.

PHSJason has listed many and I have provided links to my findings as well.

Regarding the mute... your only solution is to just turn down the TV volume but since I have no idea how you have configured your system or what form of control you are using I can not provide further comment.

Regarding Ant.1... often you can just tune in a channel and it will go to the antenna input automatically (set up a default channel macro) but I have no idea if this will work for your model. Most TVs lack a discrete antenna command these days.