FTP, identify this layer of the atmosphere that reflects radio waves at standard broadcast and shortwave frequencies.
The D region lies approximately at a height between 50 and 90 km above the surface. It has the lowest concentration of charged particles and reflects low frequency waves. The middle layers are called the Kennelly-Heaviside layers, named for the independent discoverers of this layer of the atmosphere.  The Appleton, or highest layer, has the highest concentration of charged particles due to the low density of gases.  FTP, identify this layer of the atmosphere that reflects radio waves at standard broadcast and shortwave frequencies.
The D region lies approximately at a height between 50 and 90 km above the surface.
Ionosphere