First-hop wave

{
  "id": "MLC-T-MET-010505",
  "term": "First-hop wave",
  "field": "Meteorology and atmospheric science",
  "definition": "A radio wave that has traveled from a transmitter to a receiver after undergoing a single reflection from one of the ionosphere's layers. The wave propagates upward from the ground, is refracted or reflected back toward the Earth by the ionosphere, and is then detected by a distant receiver. The maximum ground distance covered by a first-hop wave, known as the skip distance, is typically around 4,000 kilometers for reflection from the F2 layer.",
  "url": "https://mlchart.com/terminology/meteorology/first-hop-wave/"
}