D layer help

[biferi]

The D layer is the lowest layer near the Earth.

Is there any FREQ that come back down from it or is it just the other Layers that reflect the Radio Waves back down??

 

[Sonwatcher]

It seems the D-layer absorbs radio signal. Here is a quote I found about the D-layer-

The D-Layer of the ionosphere plays an interesting role. While there are no radio signals reflected off this layer it does absorb AM radio signals...

At night, the D-Layer disappears and the transmitted signal can then bounce off the ionosphere and return back to the earth.

 

[biferi]

Thanks but

what about the
stratasphere
mesophere
troposphere???????