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Propagation tool

Gray Line Propagation Countdown

Grayline propagation peaks around local sunrise and sunset when absorption and ionization briefly line up. Use the countdown below to time 40m, 30m, 20m, and sometimes 80m openings.

Grayline
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Local time

How to use it

Watch the countdown before your local sunrise and sunset, then compare the timing against your desired path. Trans-Atlantic and trans-pacific paths often improve near the terminator, especially on 20m and 40m.