Radio transmission & electromagnetic propagation

The videos below gives a short and overview of how radio waves get propagated through the medium (atmosphere) and how upper frequency bands quickly lose penetration due to physical constraints.

This also means sub-Gigahertz radio waves are a much better choice than 2.4Ghz/Wifi when you want to maximize range and penetration through dense mediums.

An explanation is also given for ionospheric reflection using the stratosphere to reflect the radio waves – this only works up to 30-40Mhz and does not apply to the 433-915mhz bands, but helps understand how very long range communication works.