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LoRa Field Test — Real-World Range of Several Kilometres

Last reviewed: 2026-09-17

Overview

This article covers a field test of a LoRa module in real-world conditions. The core question is deliberately simple: "how far can a LoRa link really go when you leave the lab?" — no ideal antenna setups, no controlled conditions, just readily available equipment pushed over real terrain.

The key mental model for LoRa:

LoRa doesn't have a long range because it's powerful, but because it can operate with extremely weak signals. This is what allows it to achieve very long distances with minimal power consumption.

The demonstrated result is a multi-kilometre link from a small, battery-powered node — enough to show that LoRa lives up to its reputation when deployed correctly.

Test Walkthrough

The walkthrough is organized in 11 stages:

Time Chapter (FR, as titled) Content
00:00 Introduction The question: real LoRa range, no lab conditions
03:01 Qu'est qu'une onde radio ? Radio wave fundamentals (frequency, propagation)
06:28 Le dBm The dBm unit — power expressed relative to 1 mW
07:58 LoRa LoRa modulation: chirp spread spectrum, long-range low-power link
10:25 Le module LoRa choisi pour le test Choice of the test module (readily available LoRa dev hardware)
13:28 Ce que dit la loi française French law: licence-free 868 MHz band, ERP and duty-cycle limits
15:00 Principe de l'essai Test principle: fixed node vs. mobile node over terrain
16:25 Principe du schéma simplifié Simplified schematic of the setup
19:06 Conception et réalisation des boîtiers radio Design & build of the radio enclosures
21:26 Préparation du test terrain Field preparation, antenna mounting, positioning
23:04 Le test de la portée terrain The actual field range test
27:34 Conclusion Results, limitations, optimizations, use cases

Key Concepts Covered

Radio waves

The theory starts with a radio-wave primer: an electromagnetic wave propagates through air at the speed of light; its behaviour depends on frequency (and thus wavelength). In the 868 MHz ISM band the wavelength is ≈35 cm, which drives antenna sizing and propagation characteristics (better penetration and diffraction than 2.4 GHz, at the cost of lower data rate).

The dBm

  • dBm = power ratio relative to 1 mW: P(dBm) = 10·log10(P/1mW).
  • Reference points used throughout: 0 dBm = 1 mW, +14 dBm ≈ 25 mW, +20 dBm = 100 mW, +27/+28 dBm ≈ 500–630 mW (high-power LoRa modules).
  • Receiver sensitivity and RSSI are also expressed in dBm — LoRa receivers go down to ≈ −137 dBm at low data rates, which is why the link budget can close over kilometres despite milliwatt-level TX power.

LoRa

  • LoRa (Semtech's chirp spread spectrum modulation) trades data rate for sensitivity: at spreading factor SF12 with 125 kHz bandwidth the payload rate drops to ~0.3 kbit/s but sensitivity reaches ~−137 dBm.
  • This is the physics behind LoRa's long range: it comes from decoding extremely weak signals, not from brute-force power.
  • Fits perfectly for sensors, IoT, trackers, off-grid messaging (Meshtastic) — small packets, long distances, battery autonomy measured in months.

The module chosen for the test

The test uses a readily available LoRa dev module — the specific board matters far less than the antenna, the mounting height and the radio parameters. Typical candidates in this class are ESP32 + SX1262 boards (e.g. Heltec LoRa32 V3/V4), which are Meshtastic/LoRaWAN-compatible — matching the current KB research thread on Meshtastic starter hardware (see Related).

What French law says

For the EU 868 MHz band used in the test:

  • 868.0–868.6 MHz (the sub-band used by LoRaWAN/Meshtastic EU default channels): max 25 mW (14 dBm) ERP, duty cycle ≤ 1% — licence-free, no individual authorisation required (ETSI EN 300 220 / ANFR framework).
  • Some other 868 MHz sub-bands allow higher power (e.g. 869.4–869.65 MHz at 500 mW), but the common LoRa channels sit in the 25 mW class.
  • The antenna must match the 868 MHz band — a 915 MHz (US) antenna on an EU node degrades range and is out of band.

[!WARNING] French/EU limits are about ERP (radiated power incl. antenna gain), not just the module's output. A high-gain antenna on a 25 mW-limited module can push you over the legal ERP — a real consideration when "improving range" (see Optimizations).

Test Methodology

Test principle

The test is a point-to-point link over real terrain:

  1. One node stays fixed (the reference end).
  2. The second node is carried/driven away across the field test area.
  3. The operator checks at increasing distances whether messages still get through, and observes signal indicators (RSSI) as the link degrades.
  4. The distance at which the link still works = the practical real-world range.

The simplified schematic of this setup is the subject of chapter 16:25 — reproduced as an editable diagram below.

Editable diagram: lora-field-range-test.drawio — open in draw.io (app.diagrams.net) to edit.

Enclosures and preparation

  • The radio nodes are housed in custom-built enclosures (design & 3D-printed fabrication is one of IHM3D's specialties), protecting the board, battery and antenna connector.
  • Field prep covers antenna mounting and node placement — height and clear surroundings matter as much as the radio itself.

Field Results & Conclusion

Results

  • The link worked over several kilometres in real conditions (hills/fields/obstacles — no ideal line of sight).
  • A small, battery-powered, low-power node reached multi-km range — impressive for milliwatt-class TX power.

Limitations encountered

  • Range depends heavily on antenna, height and radio parameters — stock antennas and ground-level placement cost most of the theoretical range.
  • Real-world obstacles and terrain break the clean free-space path; the field test exists precisely to show the gap between datasheet range and practical range.

Areas for Improvement

  • Better antenna (higher gain, correct band, mounted high).
  • Greater height (elevation is the single biggest real-world lever).
  • Radio parameter tuning (spreading factor, bandwidth, TX power within legal ERP).
  • Repeaters / meshing — with relay nodes, range extends "theoretically to tens of kilometres".

Good Use Cases

Long-range sensors, IoT, surveillance, off-grid messaging, and battery-powered autonomous systems — the sweet spot of LoRa.

Key Takeaways

  • LoRa's range comes from extreme receiver sensitivity, not transmit power — several km are reachable with ~25 mW-class modules.
  • Real-world ≠ datasheet: antenna, mounting height and terrain dominate the outcome; a field test shows what actually happens outside the lab.
  • In France/EU, 868 MHz LoRa is licence-free but ERP- and duty-cycle-limited (25 mW ERP / 1% duty on the common LoRa channels).
  • Same-class hardware (ESP32 + SX1262, 868 MHz) is what Meshtastic/Reticulum hobby networks run on — a field test like this is directly relevant to planning a private mesh.