A solar-powered, tree-mounted Meshtastic relay node operating on 433 MHz (EU_433 region). Designed for 6+ km coverage radius from an elevated forest hilltop position.
| Parameter | Value |
|---|---|
| Frequency | 433 MHz (EU_433) |
| Modem preset | LONG_SLOW |
| Device role | ROUTER |
| Target range | 6–10 km radius |
| Power | Solar + LiPo battery |
| Mounting | Tree-top, above canopy |
graph TD
SOLAR["☀️ 5V 6W USB Solar Panel"]
USB["USB-A to USB-C Cable"]
HELTEC["Heltec LoRa 32 V3.1\n433 MHz\nESP32-S3 + SX1262"]
BATT["3.7V LiPo Battery\n3000–6000 mAh\nSH1.25-2P connector"]
IPEX["IPEX/U.FL to SMA\nPigtail 15 cm"]
BULK["SMA Bulkhead\non Enclosure Wall"]
ANT["433 MHz Antenna\nGround Plane or\nFiberglass Collinear\n2.5–5 dBi"]
SOLAR -->|"5V USB"| USB
USB -->|"USB-C"| HELTEC
BATT -->|"SH1.25"| HELTEC
HELTEC -->|"U.FL"| IPEX
IPEX -->|"SMA"| BULK
BULK -->|"SMA or N-type"| ANT
subgraph ENCLOSURE["IP65 Enclosure"]
HELTEC
BATT
IPEX
end
style SOLAR fill:#f9d71c,stroke:#b8a000,color:#333
style ANT fill:#4a90d9,stroke:#2c5f8a,color:#fff
style ENCLOSURE fill:#e8e8e8,stroke:#999,color:#333
style HELTEC fill:#2d8659,stroke:#1a5c3a,color:#fff
style BATT fill:#e06040,stroke:#a03020,color:#fff
graph LR
subgraph BOARD["Heltec V3.1 Board"]
UFL["U.FL\nLoRa Port"]
USBC["USB-C\nPort"]
SH["SH1.25\nBatt Port"]
end
subgraph POWER["Power"]
SOL["5V 6W\nSolar Panel\nUSB-A out"]
LIPO["3.7V LiPo\nSH1.25-2P"]
end
subgraph RF["RF Chain"]
PIG["IPEX→SMA\nPigtail 15cm"]
BLK["SMA Bulkhead\nPanel Mount"]
ANTENNA["433 MHz\nAntenna"]
end
SOL -->|"USB-A→USB-C\ncable 1m"| USBC
LIPO -->|"SH1.25-2P\nRed=+ Black=-"| SH
UFL -->|"IPEX click-on"| PIG
PIG -->|"SMA-F"| BLK
BLK -->|"SMA-M or\nN-type adapt."| ANTENNA
style BOARD fill:#2d8659,stroke:#1a5c3a,color:#fff
style POWER fill:#f9d71c,stroke:#b8a000,color:#333
style RF fill:#4a90d9,stroke:#2c5f8a,color:#fff
Key notes:
- The Heltec V3 has built-in LiPo charge management — no external charge controller needed.
- USB-C input charges the battery AND powers the board simultaneously.
- Use a USB-A to USB-C cable (USB-C to USB-C may cause charging issues on V3).
graph TD
TIP["Tip"] --- VERT
VERT["Vertical Element\n17.3 cm copper wire\nsoldered to center pin"] --- JOIN["Solder Joint\nat Connector"]
JOIN --- CONN["SMA or N-type\nFemale Connector"]
JOIN --- R1["Radial 1 — 17.3 cm\n45° below horizontal"]
JOIN --- R2["Radial 2 — 17.3 cm\n45° below horizontal"]
JOIN --- R3["Radial 3 — 17.3 cm\n45° below horizontal"]
JOIN --- R4["Radial 4 — 17.3 cm\n45° below horizontal"]
style TIP fill:#ff6b35,stroke:#c44d1a,color:#fff
style VERT fill:#ff6b35,stroke:#c44d1a,color:#fff
style JOIN fill:#888,stroke:#555,color:#fff
style CONN fill:#555,stroke:#333,color:#fff
style R1 fill:#4a90d9,stroke:#2c5f8a,color:#fff
style R2 fill:#4a90d9,stroke:#2c5f8a,color:#fff
style R3 fill:#4a90d9,stroke:#2c5f8a,color:#fff
style R4 fill:#4a90d9,stroke:#2c5f8a,color:#fff
| Parameter | Value |
|---|---|
| Vertical element | ~17.3 cm (λ/4 at 433 MHz) |
| Radials | 4 × ~17.3 cm, angled 45° down |
| Impedance | ~50 Ω |
| Gain | ~2.5–3 dBi |
| Target SWR | < 1.5:1 |
| Material | Copper wire or brass rod, 1–2 mm |
graph TD
ANT["433 MHz Antenna\n▲ vertical, above canopy"]
MAST["PVC Pipe Mast\n1–2 m extension\nhose-clamped to tree"]
CANOPY["─── Tree Canopy Line ───"]
COAX["Coax Cable\nruns down trunk\n< 3 m ideal"]
BOX["IP65 Enclosure\n+ Heltec V3\n+ Battery\nhose-clamped to trunk"]
PANEL["Solar Panel\nmounted south-facing\n~45° tilt for LT latitude"]
ANT --- MAST
MAST --- CANOPY
CANOPY --- COAX
COAX --- BOX
BOX --- PANEL
style ANT fill:#4a90d9,stroke:#2c5f8a,color:#fff
style MAST fill:#8B6914,stroke:#5a4510,color:#fff
style CANOPY fill:#228B22,stroke:#145214,color:#fff
style COAX fill:#888,stroke:#555,color:#fff
style BOX fill:#e8e8e8,stroke:#999,color:#333
style PANEL fill:#f9d71c,stroke:#b8a000,color:#333
Mounting priorities:
- Antenna above canopy for line-of-sight
- Enclosure below canopy for rain/wind protection
- Solar panel south-facing, angled ~45°
- Coax run as short as possible (every meter of RG-174 loses ~0.3 dB at 433 MHz)
flowchart LR
A["Meshtastic\nClient Node"] -->|"LoRa 433 MHz\nLONG_SLOW"| B["Retranslator\nROUTER role"]
B -->|"LoRa 433 MHz\nre-broadcast"| C["Meshtastic\nClient Node"]
B -->|"LoRa 433 MHz\nre-broadcast"| D["Another\nRelay Node"]
D -->|"LoRa 433 MHz"| E["ATAK Node\nvia Meshtastic\nplugin"]
style B fill:#2d8659,stroke:#1a5c3a,color:#fff
style A fill:#4a90d9,stroke:#2c5f8a,color:#fff
style C fill:#4a90d9,stroke:#2c5f8a,color:#fff
style D fill:#e06040,stroke:#a03020,color:#fff
style E fill:#7b2d8b,stroke:#4e1a5a,color:#fff
The ROUTER role transparently relays all mesh traffic including ATAK CoT messages.
| # | Part | Specification | EU Source | Est. Price |
|---|---|---|---|---|
| 1 | LoRa Board | Heltec WiFi LoRa 32 V3.1, 433 MHz, ESP32-S3 + SX1262 | hamparts.shop (CZ) | ~€22 |
| 2 | Battery | 3.7V 3000–6000 mAh LiPo, SH1.25-2P connector | AliExpress: search "3.7V 6000mAh lipo SH1.25" | ~€10 |
| 3 | Solar Panel | 5V 6W USB monocrystalline, weatherproof | Amazon.de: search "6W 5V USB solar panel" | ~€12 |
| 4 | IPEX Pigtail | IPEX/U.FL to SMA female, 15 cm, RG178 | PileupDX (SE) | ~€10 |
| # | Option | Specification | EU Source | Est. Price |
|---|---|---|---|---|
| A | DIY Ground Plane | 1/4-wave, ~3 dBi, SMA/N-type | Copper wire + SMA connector | ~€3 |
| B | Ready-made GP | 433 MHz ground plane with coax pigtail | hamparts.shop (CZ) | ~€15 |
| C | Fiberglass Collinear | 433 MHz, 5 dBi, N-type, weatherproof | AliExpress: search "433MHz 5dBi fiberglass antenna N-type" | ~€20 |
| # | Part | Specification | Source | Est. Price |
|---|---|---|---|---|
| 5 | Enclosure | IP65 ABS junction box, ~150×100×70 mm | Amazon.de: search "IP65 junction box 150x100x70" | ~€8 |
| 6 | Cable Glands | PG7 or PG9 nylon, IP68, pack of 10 | Amazon.de: search "PG7 cable gland IP68" | ~€5 |
| 7 | SMA Bulkhead | SMA female bulkhead panel mount | Amazon.de / AliExpress | ~€3 |
| 8 | Self-amalgamating Tape | Silicone, for waterproofing antenna connector | Amazon.de | ~€5 |
| 9 | Silica Gel Packets | Desiccant, 5–10 g × 5 pcs | Amazon.de | ~€3 |
| # | Part | Specification | Source | Est. Price |
|---|---|---|---|---|
| 10 | Stainless Hose Clamps | Ø 80–120 mm, stainless steel, ×4 | Hardware store / Amazon.de | ~€8 |
| 11 | PVC Pipe | 25 mm diameter, 1–2 m, for antenna mast | Hardware store | ~€3 |
| 12 | UV Cable Ties | Black, UV-resistant, 300 mm, pack | Amazon.de | ~€4 |
| 13 | USB-A to USB-C Cable | 1 m, for solar panel to board | Any | ~€3 |
| # | Part | Specification | EU Source | Est. Price |
|---|---|---|---|---|
| — | Bender Case | 3D-printed case with 18650 holder, SMA port, switch | PileupDX (SE) | ~€15 |
| — | 18650 Battery | Samsung 35E or LG MJ1, 3500 mAh (genuine) | Nkon.nl (NL) | ~€6 |
| Build Variant | Components | Estimated Total |
|---|---|---|
| Budget DIY | Heltec V3 + DIY antenna + LiPo + solar + generic enclosure | ~€75 |
| Mid-range | Heltec V3 + ready-made GP antenna + Bender case + 18650 + solar | ~€90 |
| Best range | Heltec V3 + fiberglass 5dBi collinear + Bender case + 18650 + solar | ~€110 |
After flashing Meshtastic via flasher.meshtastic.org:
# Region
meshtastic --set lora.region EU_433
# Role — ROUTER disables screen, minimizes power
meshtastic --set device.role ROUTER
# Modem — LONG_SLOW for maximum link budget
meshtastic --set lora.modem_preset LONG_SLOW
# Hop limit
meshtastic --set lora.hop_limit 3
# Fixed position (adjust to your location)
meshtastic --setlat 54.68 --setlon 25.28 --setalt 200
meshtastic --set position.fixed_position true
# Disable GPS (stationary node, saves power)
meshtastic --set position.gps_mode DISABLED
# Power saving
meshtastic --set power.is_power_saving trueflowchart TD
FLASH["Flash firmware\nflasher.meshtastic.org"] --> CONNECT["Connect via\nBluetooth or USB"]
CONNECT --> REGION["Set region\nEU_433"]
REGION --> ROLE["Set role\nROUTER"]
ROLE --> MODEM["Set modem\nLONG_SLOW"]
MODEM --> POS["Set fixed position\nLat/Lon/Alt"]
POS --> GPS["Disable GPS"]
GPS --> DEPLOY["Deploy to tree 🌲"]
style FLASH fill:#4a90d9,stroke:#2c5f8a,color:#fff
style DEPLOY fill:#2d8659,stroke:#1a5c3a,color:#fff
| Shop | Country | What to Buy | Link |
|---|---|---|---|
| hamparts.shop | Czech Republic | Heltec V3.1 433MHz, GP antenna | hamparts.shop |
| PileupDX.com | Sweden | Heltec V3 433MHz, Bender case, IPEX pigtail, antennas | pileupdx.com |
| Nkon.nl | Netherlands | Genuine 18650 cells (Samsung 35E, LG MJ1) | nkon.nl |
| Amazon.de | Germany | Enclosure, cable glands, solar panel, cables, tape | amazon.de |
| AliExpress | China → EU | Fiberglass antenna, LiPo battery, adapters | aliexpress.com |
- Battery connector: Heltec V3 uses SH1.25-2P (not PH2.0). Verify polarity before connecting.
- Fake 18650 cells: Any 18650 claiming > 3600 mAh is counterfeit. Buy from Nkon.nl.
- USB-C quirk: Use USB-A to USB-C cable — C-to-C may not charge properly on V3.
- 433 MHz in EU/Lithuania: License-free ISM band (433.05–434.79 MHz), 10 mW ERP or 25 mW with duty cycle limits. Meshtastic LONG_SLOW at 10 dBm is within spec.
- ATAK compatibility: Relay transparently forwards all mesh traffic including CoT messages.