HF Planner v1.1.0 and VOACAP Online agree on which bands work. Both ranked 40m and 30m as optimal for a 550 km daytime path in the southeastern United States (EM73ts to EL89we, 10W dipole, 15 UTC). They disagree on how confident you should be.
VOACAP reported 100% reliability on 40m. HF Planner ranked the same band first but flagged it as marginal due to active geomagnetic conditions and limited WSPR spot data (8 spots). The absolute SNR values differ by 63 dB.
The gap comes from different data sources. VOACAP uses historical ionospheric medians with SSN 76 and assumes quiet geomagnetic conditions. HF Planner pulls real-time data (SFI 167, K-index 3) blended with WSPR observations and penalizes low sample confidence.
Use HF Planner for:
- Field deployment with current conditions
- Emergency communications
- Real-time decision making
Use VOACAP Online for:
- Long-term schedule planning
- Contest preparation
- Historical trend analysis