ESP32 + SX1276 gateway that fetches RTCM3 corrections from an NTRIP caster over WiFi and retransmits them via LoRa 433 MHz to the receiver. Built around a commodity LoRa development board (no custom PCB), so this BOM lists ready-made modules and the few external parts that complete the build.
| Qty | Part | Description | Notes | Est. USD |
|---|---|---|---|---|
| 1 | LoRa dev board: TTGO T-Beam V1.1 (recommended) or LoRa32 | ESP32 + SX1276 (433 MHz) + SSD1306 OLED | T-Beam adds GPS + 18650 holder + PMU; firmware env ttgo-t-beam |
22–35 |
| 1 | 433 MHz LoRa antenna | SMA dipole; yagi/directional for range | Must be 433 MHz, not 868/915 | 3–10 |
| 1 | 18650 Li-ion cell (3.7 V) | Field power; holder is on the T-Beam | Or power via USB-C | 5–9 |
| 1 | USB-C cable | Programming / power | — | 2–4 |
| Qty | Part | Description | Est. USD |
|---|---|---|---|
| 1 | SSD1306 128x64 OLED | Only if the board lacks one (LoRa32 variants) | 3–5 |
| 1 | WiFi/LTE uplink | Onboard ESP32 WiFi, or external LTE router/hotspot for internet path | varies |
| 1 | Enclosure (weatherproof if outdoor) | Field deployment | 5–20 |
| 1 | SMA pigtail / extension | Mount antenna externally | 2–5 |
Indicative total: ~$35–60 (T-Beam + 433 MHz antenna + battery).
NSS → GPIO18 MOSI → GPIO27 MISO → GPIO19
SCK → GPIO5 RST → GPIO23 DIO0 → GPIO26
I2C: SDA → GPIO21, SCL → GPIO22
| Parameter | Value |
|---|---|
| Frequency | 433 MHz (433.7 MHz to match receiver default) |
| Spreading factor | 7 |
| Bandwidth | 125 kHz (receiver default is 500 kHz — keep both identical) |
| Coding rate | 4/5 |
| TX power | 20 dBm (SX1276 max) |
| Sync word | 0x12 |
⚠️ The LoRa radio parameters (frequency, SF, bandwidth, sync word) must be identical on transmitter and receiver or the link fails silently.