Propagation Frequency Planner
Estimate which amateur-radio HF bands are likely open between two locations. This is a simplified model assuming moderate solar activity (SSN ≈ 100); real-world conditions vary with the solar cycle, geomagnetic activity, and local ionospheric weather.
Path summary
Daily overview
Best band quality by hour for this QSO. Click an hour to load its full prediction.
Band-by-band prediction
| Band | Freq | Quality | Min. TX | Propagation mode | Notes |
|---|
About this planner
This tool provides rough estimates based on a simplified ionospheric model. Key assumptions and design choices:
- Solar activity
- By default, the model assumes a moderate smoothed sunspot number (SSN ≈ 100). Enable live space weather data to use the current SSN from NOAA/SWPC instead. During solar minimum, the higher bands (10–17 m) will open far less often; during solar maximum, they may open even more than predicted.
- Day/night band behaviour
- Lower bands (160 m, 80 m, 40 m) favour nighttime propagation: the D layer disappears after sunset, dramatically reducing absorption on these frequencies. Higher bands (20 m and above) favour daytime propagation when the F2 layer is strongly ionised. The 30 m band sits at the transition and can work in both conditions. The map shows the solar terminator so you can see which parts of the path are in darkness.
- Propagation modes
- The planner evaluates ground wave, NVIS (Near Vertical Incidence Skywave for paths under ~500 km), single- and multi-hop F2-layer skywave, E-layer skywave, sporadic E (summer), and gray-line enhancement. It does not model tropospheric ducting, meteor scatter, EME, or other VHF/UHF modes.
- Power estimates
- Minimum TX power assumes half-wave dipole antennas at both ends, 10 dB SNR in a 2.4 kHz SSB bandwidth, and median atmospheric noise from ITU-R P.372. Real-world power requirements are typically 2–5× higher due to antenna inefficiency, man-made noise, fading, and QRM.
- Geomagnetic conditions
- By default, the model assumes quiet geomagnetic conditions (K index ≈ 0–2). With live space weather data enabled, the planner uses the NOAA/SWPC Kp index forecast for predictions within the next three days, reducing foF2 estimates during disturbed or storm conditions. Effects are strongest on high-latitude and polar paths. During geomagnetic storms, HF propagation can be severely disrupted.