Plain-language answer: Short path follows the shorter great-circle route between stations; long path follows the complementary route around the other side of Earth.
Why operators care
Different daylight, ionization, absorption, noise, and headings can make the longer route stronger at particular times.
What to compare on air
Rotate a directional antenna through both calculated bearings and compare timing, delay, and signal behavior.
The common mistake
Calling a signal long path solely because it sounds delayed or fluttery.
Forecast boundary
Space-weather indices and propagation models describe probabilities and regional conditions. A usable contact still depends on the exact path, time, frequency, antenna pattern, noise, power, and current observations.
