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: ~17 mA in continuous LoRa receive (RAK datasheet), ~125 mA transmit at 22 dBm (SX1262 ~118 mA per Semtech, plus MCU). Sleep is ~2.0 µA. A ~3 mA figure would be a duty-cycled/averaged idle value, not steady receive.
- Average power: ~8-15 mA in typical repeater operation (estimate; actual average depends on RX duty cycle and traffic - mostly RX at ~17 mA with brief TX bursts and low-power sleep between)
- 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 approximate whole-board current with ESP32 WiFi active, ~30 mA (WiFi off, LoRa only; depends on GPS on/off and CPU activity). Both are board-level estimates, not single datasheet values.
- 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-n5262 / HT-n5262M (nRF52840 + SX1262)
Ultra-compact option for space-constrained installations:
- Current draw: Comparable to the RAK4631 (both are nRF52840 + SX1262): expect ~17 mA continuous LoRa RX, ~125 mA TX at 22 dBm, microamp-range sleep. Verify against Heltec's datasheet for the specific variant.
- Advantages: Extremely small form factor (the HT-n5262M is a 1.27 mm stamp-hole solder-down module for integration onto your own PCB). Note: the bare module does not include a LiPo/JST connector; a built-in battery connector applies only to a dev-board variant - confirm the variant you are buying.
- 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 bridge (GPS is largely unusable indoors without sky view, so position tracking applies only to an outdoor/rooftop gateway) |
| 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. Verify the supported host hardware and architecture against docs.meshcore.io Room Server requirements before deploying. |
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. Note for unlicensed US (Part 15.247) operation: antenna gain above 6 dBi requires a dB-for-dB reduction in conducted transmitter power, so high-gain Yagis above 6 dBi must be paired with a correspondingly lower TX power setting.
- Antenna cable: LMR-195 or LMR-400 (minimize cable length to reduce loss). LMR-400 has ~1.3 dB/10 m (12.8 dB/100 m, 3.9 dB/100 ft) loss at 900 MHz per the Times Microwave datasheet.
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