Editing Ground wave (section)

{{Short description|Radio wave propagating along the Earth's surface}}
{{broader|Surface wave}}

'''Ground wave''' is a mode of [[radio propagation]] that consists of [[Electric current|currents]] traveling through the [[Soil|earth]]. Ground waves propagate parallel to and adjacent to the surface of the Earth, and are capable of covering long distances by [[Diffraction|diffracting]] around the Earth's curvature. This radiation is also known as the '''Norton surface wave''', or more properly the '''Norton ground wave''', because ground waves in radio propagation are not confined to the surface. Groundwave contrasts with [[line-of-sight propagation]] that requires no medium, and [[skywave]] via the ionosphere. 

Ground wave is important for radio signals below 30 MHz, but is generally insignificant at higher frequencies where line-of-sight propagation dominates. [[AM broadcasting|AM]] and [[longwave]] broadcasting, navigation systems such as [[Loran-C|LORAN]], low-frequency [[Time signal|time signals]], [[Non-directional beacon|non-directional beacons]], and short-range [[High frequency|HF]] communications all make use of it. Range depends on frequency and [[ground conductivity]], with lower frequencies and higher ground conductivity permitting longer distances.<ref name=":0">{{Cite book |url=https://extranet.itu.int/brdocsearch/R-HDB/R-HDB-59/R-HDB-59-2014/R-HDB-59-2014-PDF-E.pdf |title=Handbook on Ground Wave Propagation |vauthors=Angulo I, Barclay L, Chernov Y, Deminco N, Fernández I, Gil U, Guerra D, Milsom J, Peña I, De la Vega D |publisher=[[International Telecommunication Union]] |year=2014 |isbn=978-92-61-18661-6 |location=Geneva, Switzerland |format=PDF |access-date=23 July 2024}}</ref>