2mm is the wavelength, not the effective width (think of a laserbeam) of the wave. and yes, even with a laser (nanometer wavelengths) it's hard to produce a 2m

2mm is the wavelength, not the effective width (think of a laserbeam) of the wave. and yes, even with a laser (nanometer wavelengths) it's hard to produce a 2mm wide beam at a helicopter distance.