Long Path Propagation: Reaching DX the Other Way Around
Long path is HF propagation that routes a signal the “long way around” earth instead of the direct great-circle path. For any two points on the globe, there are two great-circle paths: the short path (direct) and the long path (the other way, 180 degrees opposed). When the long path passes through favorable conditions (mostly darkness or grey line) while the short path passes through unfavorable conditions (full daylight, geomagnetic disturbance), the long path can produce a stronger signal even though it covers far more distance.
Why it matters for HF operating
Long-path operating is how stations on opposite sides of the world reach each other when the short path is closed. From the U.S. East Coast to Japan, the short path crosses high latitudes that suffer from auroral absorption. The long path runs across South America and the South Pacific, often in darkness, and can produce stronger signals for hours at a time. Long-path contacts are common on 20 meters and 40 meters at sunset and sunrise on either end.
Key values to know
- Bearing. Long-path bearing is exactly 180 degrees from the short-path bearing.
- Distance. Long path is longer than 20,000 km by definition. Most long-path contacts cover 25,000 km or more.
- Best bands. 20 meters, 17 meters, and 40 meters carry most long-path activity.
- Best timing. When most of the long path is in darkness or aligned with the grey line. From the U.S. East Coast, that is often morning and evening.
- Antenna. Long-path operating favors low-angle antennas (high horizontals or vertical arrays) that put energy at 5 to 10 degrees above the horizon.
Common misconceptions
A long-path signal is not necessarily weaker than a short-path signal. The short path can be heavily absorbed (high D-layer attenuation, geomagnetic disturbance, or daylight on critical bands) while the long path is in favorable conditions. Operators sometimes assume the louder signal must be on the short path; checking the bearing with a beam antenna is the only way to know for sure. A 180-degree heading mismatch is a clear sign of long-path operation.
Related terms
- Grey line: frequently aligns with long-path openings
- F2 layer: the reflective layer that carries long-path hops
- Geomagnetic storm: often closes short paths and forces long-path workarounds
- Aurora propagation: the high-latitude phenomenon long path frequently routes around
- MUF: the path-specific ceiling that long path must respect
SkyWave shows long-path bearings and predicted windows to popular DX regions on the Go screen, so you can plan for sunrise and sunset openings. See it in the app →