# RFCP Session 2026-02-04 — Complete Development Log

**Session:** February 4, 2026 (afternoon/evening)
**Duration:** ~6 hours active development
**Iterations completed:** 3.9.0 → 3.9.1 → 3.10.0 → 3.10.1 → 3.10.2 → 3.10.3 → 3.10.4 (pending)

---

## What Was Done This Session

### Infrastructure: terra.eliah.one Tile Server ✅
- **DNS:** terra.eliah.one → 2.56.207.143 (VPS A, Hayhost)
- **Caddy:** File server with browse at /opt/terra/tiles/
- **SRTM3 (90m):** 187 tiles, 514.5 MB — full Ukraine (N44-N51, E018-E041)
- **SRTM1 (30m):** 160 tiles, 3,957.3 MB — full Ukraine (N44-N51, E022-E041)
- **Sources:** viewfinderpanoramas.org (SRTM3, void-filled), AWS S3 elevation-tiles-prod (SRTM1)
- **Index:** /api/index → tile_index.json (version 2, dual dataset)
- **Public access verified:** https://terra.eliah.one/srtm1/ and /srtm3/

### Iteration 3.9.1: Terra Integration ✅
- terrain_service.py updated with prioritized SRTM sources:
  1. terra.eliah.one/srtm1/ (30m, preferred)
  2. terra.eliah.one/srtm3/ (90m, fallback)
  3. AWS S3 skadi mirror (public fallback)
- New endpoints: /api/terrain/status, /api/terrain/download, /api/terrain/index
- Auto-downloads tiles on first use, cached permanently on disk
- 173 tiles loaded (4,278.6 MB) confirmed in Data Cache panel

### Iteration 3.10.0: Link Budget + Fresnel Zone + Interference ✅
- **Link Budget Calculator:** Full TX→RX path analysis panel
  - EIRP calculation, FSPL, terrain loss, received power, link margin
  - RX point placement on map (orange marker, dashed line)
  - ✓ LINK OK / ✗ FAIL status with margin display
- **Fresnel Zone Visualization:** On Terrain Profile chart
  - First Fresnel zone ellipse overlay (semi-transparent)
  - Red highlighting where terrain intrudes zone
  - Frequency-aware (zone size changes with MHz)
  - Clearance calculation with recommendation text
- **Interference Modeling (C/I):** Backend ready
  - Carrier-to-interference ratio per grid point
  - Co-frequency site grouping
  - GPU-accelerated (CuPy vectorized)

### Iteration 3.10.1: UI Bugfixes (partial) ✅
- Elevation opacity control
- Data Cache panel with region downloads
- Various dark theme text fixes

### Iteration 3.10.2: Tool Mode System ✅
- **ActiveTool state:** 'none' | 'ruler' | 'rx-placement' | 'site-placement'
- Single map click handler dispatches to active tool
- Cursor management (default/crosshair/cell per tool)
- Ruler snap-to-site (20px threshold)
- Event propagation fixes (partial — terrain profile still leaks)

### Iteration 3.10.3: Calculator Button + Ruler Limit ✅
- Calculator button added to right toolbar
- Ruler limited to 2 points max (point-to-point only)
- Third click starts new measurement

### Iteration 3.10.4: Pending Fixes 🔧
- Terrain Profile click-through (needs stopImmediatePropagation on native event)
- TX Height hardcoded to 2m in Link Budget (should read from site config)

---

## Current State — What Works

### Core Features ✅
- Multi-site RF coverage planning with multi-sector antennas
- GPU-accelerated coverage calculation (RTX 4060, CuPy/CUDA)
- 9 propagation models (Free-Space, terrain_los, buildings, materials, dominant_path, street_canyon, reflections, water_reflection, vegetation, atmospheric)
- Performance: 11.2s Full preset (17.4x speedup from v3.8.0)
- Geographic-scale heatmap with Leaflet tile rendering

### Terrain Integration ✅
- SRTM elevation data (30m and 90m resolution)
- Bilinear interpolation for sub-pixel accuracy
- Memory-mapped I/O with LRU cache (20 tiles)
- Auto-detection SRTM1 vs SRTM3 by file size
- Terrain-aware coverage calculation (Line of Sight, terrain loss)
- Terrain Profile viewer with elevation chart

### Analysis Tools ✅
- **Link Budget Calculator** — point-to-point path analysis
- **Fresnel Zone Visualization** — on terrain profile chart
- **Ruler/Distance Measurement** — 2-point with snap-to-site
- **Terrain Profile** — elevation cross-section between 2 points
- **Coverage Statistics** — Excellent/Good/Fair/Weak breakdown
- **Session History** — compare calculation runs

### Data Management ✅
- Export: CSV, GeoJSON coverage data
- Import/Export: Site configurations (JSON)
- Data Cache: Regional tile pre-download (Ukraine, Eastern Ukraine, Donbas, Central, Western, Kyiv)
- 173 terrain tiles (4.3 GB) cached locally

### Infrastructure ✅
- Frontend: React 18 + TypeScript + Vite + Leaflet
- Backend: Python FastAPI + CuPy GPU pipeline
- Tile Server: terra.eliah.one (Caddy file_server)
- Packaging: PyInstaller + Electron (Windows installer)
- Desktop app: RFCP - RF Coverage Planner (native window)

---

## Known Bugs (for 3.10.4+)

| # | Bug | Severity | Root Cause |
|---|-----|----------|------------|
| 1 | Terrain Profile click places ruler point | Medium | stopPropagation not blocking Leaflet's native DOM listener. Need `e.nativeEvent.stopImmediatePropagation()` or move popup outside Leaflet container |
| 2 | TX Height shows 2m in Link Budget | Low | Hardcoded default, not reading from site config field |
| 3 | Cursor still shows hand in some cases | Low | Leaflet default grab cursor not fully overridden |
| 4 | Elevation Colors opacity slider | Low | May need correct layer reference binding |

---

## Roadmap — Updated February 4, 2026

### ✅ COMPLETED (Iterations 1-3.10.3)

**Phase 1: Foundation** (Dec 2024)
- React + TypeScript + Vite + Leaflet setup
- Basic site management, coverage calculation

**Phase 2: Core Features** (Jan 2025, Iterations 1-10.1)
- Multi-site, multi-sector, geographic heatmap
- Coverage statistics, keyboard shortcuts
- Code audit, production polish

**Phase 3: GPU Acceleration** (Feb 2-3, 2026, Iterations 3.1-3.8)
- CuPy/CUDA pipeline: 195s → 11.2s (17.4x)
- PyInstaller build with CUDA bundling
- Windows native backend (no WSL2)

**Phase 4: Terrain Integration** (Feb 4, 2026, Iterations 3.9-3.10)
- SRTM tile server (terra.eliah.one)
- 347 tiles, 4.5 GB, full Ukraine coverage
- Terrain-aware propagation, terrain profiles
- Link budget calculator, Fresnel zones
- Tool mode system, interference modeling

### 🔧 REMAINING ON CURRENT STACK

**3.10.4: Final Bugfixes** (1-2 hours)
- Terrain Profile click propagation fix
- TX Height from site config
- Cursor cleanup
- Elevation opacity fix

**3.11: Polish & QA** (optional, 2-3 hours)
- Interference C/I heatmap toggle on frontend
- Coverage comparison mode (before/after)
- Keyboard shortcuts help modal (?)
- Settings persistence (localStorage)
- Input validation improvements

**3.12: Offline Package** (optional, 2-3 hours)
- SRTM3 tiles bundled in installer (~180 MB gzipped)
- SRTM1 as optional "HD Terrain Pack" download
- First-run extraction to data/terrain/
- Full offline operation without internet

### 🔮 FUTURE (New Stack — When Inspired)

**Stack Migration: Tauri + SvelteKit + Rust**
- Native performance without Electron overhead
- Rust backend replacing Python FastAPI
- GPU compute via wgpu or Vulkan
- Smaller installer (<100 MB vs current ~1.6 GB)
- Already tested Tauri for UMTC Wiki project

**Advanced RF Features:**
- 3D terrain visualization (Three.js or WebGPU)
- Drive test data import and comparison
- Multiple frequency band planning
- Custom propagation model editor
- Real-time collaboration (via Matrix?)

**Field Deployment:**
- Live USB with BitLocker encryption
- Offline-first with full Ukraine terrain
- Integration with UMTC tactical mesh
- LoRa/IoT device position planning

---

## Tech Specs Quick Reference

### Backend
```
Location: D:\root\rfcp\backend
Framework: FastAPI + Uvicorn
GPU: CuPy + CUDA (RTX 4060)
Python: 3.x with numpy, scipy, httpx
Build: PyInstaller ONEDIR (~1.6 GB with CUDA)
Start: python -m uvicorn app.main:app --host 0.0.0.0 --port 8000
```

### Frontend
```
Location: D:\root\rfcp\frontend
Framework: React 18 + TypeScript + Vite
Map: Leaflet + custom geographic heatmap
State: Zustand
Build: npm run build → dist/
Bundle: 163KB gzipped
```

### Tile Server
```
Domain: terra.eliah.one
Server: VPS A (2.56.207.143), Caddy file_server
Path: /opt/terra/tiles/srtm1/ and /opt/terra/tiles/srtm3/
Index: /api/index → tile_index.json
Health: /health → "ok"
Tiles: 187 SRTM3 (515 MB) + 160 SRTM1 (3.9 GB)
```

### Key Files
```
terrain_service.py — SRTM tile loading, bilinear interpolation, elevation profiles
gpu_service.py — CuPy/CUDA coverage calculation pipeline
coverage_service.py — Propagation models, coverage orchestration
routes/terrain.py — /api/terrain/status, /download, /index
routes/coverage.py — /api/link-budget, /api/fresnel-profile
frontend/src/store/tools.ts — ActiveTool state management
frontend/src/components/panels/LinkBudgetPanel.tsx
frontend/src/components/map/TerrainProfile.tsx
frontend/src/components/map/MeasurementTool.tsx
```

---

## Performance Benchmarks

| Preset | Resolution | Points | Time | GPU |
|--------|-----------|--------|------|-----|
| Standard | 200m | 1,975 | 7.4s | ✅ |
| Full | 50m | 6,639-6,662 | 11.2-11.7s | ✅ |
| 50km radius | 200m | 4,966 | ~30s | ✅ |

**GPU:** NVIDIA RTX 4060 (CUDA)
**Speedup:** 17.4x vs CPU-only (v3.7.0 baseline)

---

## Session Notes

Продуктивна сесія. За ~6 годин:
- Підняли tile server з нуля (terra.eliah.one)
- 347 тайлів terrain data для всієї України
- Інтегрували terrain в backend (auto-download, status API)
- Додали Link Budget Calculator, Fresnel Zone, Interference modeling
- Впровадили Tool Mode System для вирішення click conflicts
- Виправили купу UX багів

Продукт близький до завершення на поточному стеку. Основна функціональність працює, залишились polish баги та optional фічі. Рефактор на Tauri+SvelteKit+Rust — коли буде натхнення, не терміново.

Half Sword скачаний і чекає. 🗡️