Fixed Infrastructure Node Hardware Selection
Fixed infrastructure nodes - backbone repeaters, room server hosts, and long-term outdoor installations - have different hardware requirements than portable client nodes. Reliability, power efficiency, and maintainability are the priorities.
Primary Hardware Candidates
RAK4631 (nRF52840 + SX1262)
The RAK4631 WisBlock core is the most popular choice for fixed infrastructure in 2025-2026:
- Current draw: ~3 mA in LoRa receive (idle), ~80 mA transmit at 22 dBm
- Average power: 8-15 mA in typical repeater operation
- Advantages: Modular WisBlock system allows easy sensor/GPS/display add-ons; nRF52840 has excellent power management; SX1262 supports all required frequencies
- Form factor: Small enough to fit in an IP67 enclosure with a 18650 battery pack
- Firmware: MeshCore (REPEATER or Companion), Meshtastic
LILYGO T-Beam Supreme (ESP32-S3 + SX1262)
Good choice when WiFi/MQTT gateway capability is needed at a fixed site:
- Current draw: ~80-120 mA (ESP32 WiFi active), ~30 mA (WiFi off, LoRa only)
- Advantages: Built-in GPS, WiFi for MQTT bridge, USB-C, relatively large community
- Disadvantages: Higher power draw than nRF52 makes solar budget larger; ESP32 requires periodic watchdog resets in some deployments
- Best for: Gateway nodes with internet connectivity, sites with reliable grid or large solar panels
Heltec HT-n62 (nRF52840 + SX1262)
Ultra-compact option for space-constrained installations:
- Current draw: Very similar to RAK4631; nRF52840-based
- Advantages: Extremely small form factor; built-in LiPo connector
- Best for: Discreet indoor deployments, installations with severe space constraints
Hardware Selection Matrix
| Use Case | Recommended Hardware | Reason |
|---|---|---|
| Solar outdoor repeater | RAK4631 | Lowest power, weatherproof WisBlock ecosystem |
| Indoor backbone with internet gateway | T-Beam Supreme | WiFi for MQTT, GPS for position tracking |
| High-altitude remote repeater | RAK4631 | Low power essential for limited solar; reliable firmware |
| Room Server host: RAK4631 or Heltec V3 running MeshCore Room Server firmware | RAK4631 via USB serial | Pi handles room server; RAK handles LoRa radio |
Antenna Considerations for Fixed Sites
Infrastructure nodes should use external antennas rather than the stub antennas included with most development boards:
- Omnidirectional (5-8 dBi fiberglass): Best for covering 360 degrees; mount at highest practical point
- Yagi/directional (10-15 dBi): Best for point-to-point backbone links over long distances; requires careful alignment
- Antenna cable: LMR-195 or LMR-400 (minimize cable length to reduce loss; LMR-400 has ~1 dB/10m loss at 915 MHz)
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