What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation?

Radio signals bouncing off the ionosphere can reach a distant receiver by taking the most direct route across the globe (short-path) or by traveling the opposite way around the world (long-path). Even though radio waves travel at the speed of light, the long-path route is tens of thousands of miles longer than the short-path route. This significant difference in distance creates a very slight, yet measurable, delay in the signal's travel time. When your receiver picks up both the short-path and the long-path signals at the exact same time, this fraction-of-a-second time difference manifests as a distinct, slightly delayed echo. While local multipath interference might cause severe phase cancellation, a noticeable echo is the classic hallmark of simultaneous short-path and long-path global propagation.