Originally Posted by JetPlaneFlyer
Well actually not quite as bad as line of sight. Unlike sight 2.4GHz will pass though glass fibre, wood, film covering and/or foam without any real problem. If you consider your home 2.4GHz wireless connection that will actually pass through walls and closed doors etc albeit with reduced range.
It's metal and carbon fibre that block it outright so your batteries and motor and such like will cause shadows, hence the multiple aerials so they don't all get shadowed at once.
And dirt. Just try flying behind a little hill and bad stuff happens really fast. The planet makes a fine 2.4 GHz barrier. Even flying behind a sand dune blocks the signal. Don't ask how I know.....