Definition
The distance along the Earth's surface between a high-frequency (HF) radio transmitter and the nearest point where its sky wave returns to the ground after reflecting off the ionosphere. Within the skip distance, the signal cannot be received because the ground wave has already faded out and the sky wave has not yet come back down.
Plain English
A gap on the ground around an HF radio transmitter where the signal can't be heard. The signal travels up, bounces off the upper atmosphere, and comes back down some distance away — the area in between is silent.
Context Anchor
Seen in discussions of long-range radio communication and radio signal coverage.
Derivation
From 'skip,' meaning to bounce or pass over something. The signal literally skips over a portion of the Earth's surface — like a stone skimming across water — before touching down again.
Why Pilots Care
Pilots must account for skip zones where no communication is possible, allowing them to select frequencies that maintain reliable contact.
Analogy
Think of skipping a stone across a pond. The stone leaves your hand, flies through the air, and only touches the water some distance away. Anyone standing between you and that landing spot never sees it touch down.
Grounding Statement
There can be a zone where a radio station is not received well because the signal has not yet returned to the ground.
Intuition Check
“Skip” does not mean leaving something out here. It means the radio signal travels upward and returns to Earth some distance away.
Example Sentence 1
The crew couldn't reach the oceanic controller on the assigned HF frequency because they were inside the skip distance, so they switched to a lower frequency to shorten the gap.
Example Sentence 2
Changing to a lower frequency reduced the skip distance and restored voice communication with the distant station.