Maritime / Horizon Plots¶
Specialized plots for on-water antenna analysis — where the link almost exclusively lives in a narrow band around the horizon.
What "horizon band" means¶
A horizon band is defined by two $\theta$ angles around 90° (equator of the sphere): e.g., $\theta = 85°$ to $\theta = 95°$ for a 10°-wide horizon. Everything outside that band wastes power for maritime links.
Five plot types¶
| Plot | Purpose |
|---|---|
| Mercator heatmap | Flat $\phi$-vs-$\theta$ map of gain |
| Conical cuts | Gain vs $\phi$ at each $\theta$ in the horizon band |
| Gain-over-azimuth | Horizon-band average gain vs $\phi$ (a single curve) |
| Horizon statistics table | Numerical summary: avg, max, min, advantage |
| 3D pattern with band highlight | 3D sphere with the horizon band visually emphasized |
Maritime metrics¶
| Metric | Definition |
|---|---|
band_avg_dB |
Sin-weighted average gain inside the horizon band |
full_avg_dB |
Sin-weighted average gain over the full sphere |
band_advantage_dB |
band_avg_dB - full_avg_dB. Positive = horizon-favored antenna |
| Maritime Power Fraction (%) | Fraction of total radiated power inside the band. 50% = isotropic; > 50% = horizon-favored |
| Horizon Efficiency | Same as band_advantage_dB, displayed alongside conducted-power efficiency when available |
In the GUI¶
After loading a passive or active scan, the Maritime tab appears (if maritime plots are enabled in settings). Configure $\theta_{\text{start}}$ and $\theta_{\text{stop}}$ in degrees.
Programmatic / MCP¶
bulk_process_passive and bulk_process_active both return maritime metrics in their result rows:
process_folder("/path/to/lab/captures", intent="passive", report=True)
# Each result row includes band_advantage_dB and maritime power fraction.
Why "Maritime Power Fraction" was added (v4.1.8)¶
The earlier "Horizon Efficiency" metric was confusingly close to 50% even for an isotropic antenna (because half the sphere's solid-angle is in any 180°-symmetric band). The dB-form band_advantage_dB is the right metric — 0 dB means isotropic, positive means horizon-favored. Both are shown for traceability.