Using lasers to communicate

[SINCLAIR DOUGLAS N]

> >An interception device will stick out like dogs balls.  Whoever wants to tap
> >my line is going to have to build a tower.
> 
> Depends upon how paranoid you want to be.  A small radio-controlled
> helicopter is available cheaply at Radio Shack, and might even be
> capable of holding a receiver, re-transmitter and recorder.


If I wanted to intercept a laser beam I'd spray an aerosol mist
into the beam and look at the scatter.  On a dusty or humid day I
might not need the aerosol.

Why not just encrypt the link?  Then anyone can tap and it doesn't matter.
I'm in the process of building a tightbeam microwave link that can carry
2 Mbps over 50Km.  Anybody got any gunn transceivers they don't need?