Radio silence?

Okay, I ran across a little issue, and was hoping others may have seen it. I was undertaking a rather long flight from Christchurch, NZ to Santiago, Chile. Not too long after reaching cruise altitude I lost all radio contact. Well, to be more specific, here's the rundown:1) I'd been handed off to NZ Center, but hadn't contacted them.2) I occasionally hit the "`" key to see what center I'm supposed to be in contact with.3) After reaching cruise altitude, the ATC screen would not pop-up.4) This situation remained until I was 130nms from Santiago. My flightplan route was a direct GPS flight, and it flies something of a Great Circle route. Is it normal on this type of route to lose radio contact, especially for so long a time? Or is this just a quirky thing I ran across on this particular flight?Anyone run across this before? Thanks!!!Rob D.