Antenna LoRa
To maximize LoRa range, antenna placement is everything — even more than transmit power. With good antenna positioning and line-of-sight, 10+ km range is very realistic.
Here’s a breakdown to help you get the best possible range from your RAK WisBlock or custom node setup:
🧭 Antenna Placement Best Practices
✅ 1. Get it HIGH
- Elevation = range
- Mount antennas:
- On rooftops
- On tall poles or towers
- In trees or on hilltops
- Even 2–3 meters above ground gives major gains
- For mobile/portable: use backpack-mounted pole or strap to tall objects
✅ 2. Clear Line of Sight (LoS)
- Ideal: direct view between antennas
- Avoid:
- Trees, walls, buildings, cars, hills
- Metal obstructions or reflective surfaces
- If perfect LoS isn’t possible, aim for “Fresnel zone” clearance — even partial blockage here drastically reduces range
✅ 3. Orientation (Polarization)
- Match vertical ↕ or horizontal ↔ orientation between antennas
- Most LoRa antennas are vertically polarized — keep them pointing straight up
- If one antenna is vertical and the other horizontal = signal loss of ~20 dB
📡 Recommended Antenna Types for Long Range
| Type | Notes | Example Range |
|---|---|---|
| Rubber duck (default stubby) | OK for testing, limited range | 0.5–1 km urban |
| 1/4 wave whip | Good general-purpose, ~8 cm at 915 MHz | 1–5 km |
| 5 dBi fiberglass omni | Great for base stations (roof/pole mount) | 5–10+ km |
| Yagi directional | High gain, very directional | 10–20+ km (point-to-point only) |
| Helical (compact coils) | Used on boards, limited performance | 0.2–0.5 km |
| Ground plane antenna | Custom DIY for big gains | 3–8 km, portable friendly |
Optional: DIY High-Gain Antenna Projects
If you want to avoid China-made antennas, you can build your own 915 MHz antenna easily:
🔩 1. 1/4 Wave Whip
- Length = 1/4 of wavelength at 915 MHz ≈ 82 mm
- Use solid copper wire, mount vertical
- Add a small ground plane (metal disc, can, or radial wires)
📐 2. Ground Plane Antenna
- Central wire = 82 mm
- Four ground radials = also 82 mm, angled ~45°
- Can be made from coat hangers or brass welding rods
⚠️ Don’t Forget:
- Use 50-ohm coax cable (like RG-316 or RG-58) if extending antennas
- Keep coax as short as possible — cable loss kills signal
- SMA connectors: make sure you match SMA vs RP-SMA type
✅ Antenna Placement Checklist
| Task | Status |
|---|---|
| Mount above surrounding objects (rooftop, tower) | ✅ |
| Use vertical orientation | ✅ |
| Ensure no big metal objects near base | ✅ |
| Match polarization (vertical ↕ both ends) | ✅ |
| Avoid long coax runs | ✅ |
| Use proper gain antenna (e.g., 5 dBi omni) | ✅ |
| Clear Fresnel zone (as much as possible) | ✅ |