At what height do navigation compasses stop working?
How to Use a Compass [EASY Step-by-Step Tutorial] – Greenbelly Meals
How far up would you have to go for a compass to stop working? - Quora
Why does a compass only work horizontally? Is it simply because of how a modern compass is made, or is it strictly the Earth's magnetic pole? - Quora
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At what altitude do compasses cease to work? : r/askscience
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How far up would you have to go for a compass to stop working? - Quora
Celestial navigation - Wikipedia
LC450 Outdoor Car Compass/Guide Ball Adjustable Angle N8R2
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