Lego IR Receivers - How do they work?

[barakamon]

I'm on the planning stages of getting my Technic Arocs RC'ed, but having never worked with IR receivers as of yet, I am not sure how they work. Do they have to be visible or "within sight" from the controller's viewpoint all the time? Would hiding it inside the cab make transmission issues? 

[xPETEZx]

AS with anything IR, they will need line of sight.

Take placement inspiration from sets which already have them. Typically roof mounted so just the IR dome sticks out works best.

If you put them in the cab you might find that you can only control the trunk from the front through the open windows.