Offline Tool
HF Propagation Advisor
This advisor turns solar flux (SFI) and K-index into a rough HF band pick. It is a planning hint for NVIS and Winlink, not a substitute for listening on the air.
Offline band suggestions from SFI and K-index. Works offline after your first visit.
This advisor turns solar flux (SFI) and K-index into a rough HF band pick. It is a planning hint for NVIS and Winlink, not a substitute for listening on the air.
Higher SFI generally favors higher bands (15/12/10 m). K-index 4 or above often means absorption and noisy low bands. For East Tennessee regional emcomm you usually want NVIS — 80 m at night, 40 m by day — which cares more about a low dipole than about 10 m openings. Use the NVIS advisor next to this page.
When online, fetch a live solar snapshot; when offline, type the last numbers you wrote on the go-bag card. Then pick an RMS gateway on Winlink or a net on HF nets (Tennessee Phone Net and emergency HF).
Appalachian terrain creates skip-zone surprises. A 40 m NVIS dipole at 15 feet often outperforms a trapped vertical for in-state traffic. Walkthrough: NVIS for Appalachian emcomm.
See also: HF traffic hub · Digital emcomm
A daily index of solar radio emissions at 10.7 cm; higher values generally favor higher HF bands.
A geomagnetic activity index from 0–9; values of 4+ often mean HF absorption and disturbed conditions.
No. Use the band that is open for the path you need. NVIS 80/40 m still works on mediocre solar days.
When the fetch button works, it pulls a public solar feed. Treat it as advisory; WWV at 10/15/20 MHz is the on-air check.
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