Приземна вълна (ground wave) / повърхностна вълна (surface wave)
https://vu2nsb.com/radio-propagation/gro...opagation/
https://vu2nsb.com/radio-propagation/gro...opagation/
https://vu2nsb.com/radio-propagation/gro...opagation/
https://vu2nsb.com/radio-propagation/gro...opagation/