# Understanding the Technology # What Is LoRa? (For Beginners) LoRa stands for "Long Range." It is a radio modulation technique from Semtech that enables very long range wireless communication at very low power, at the cost of low data rates - the physical layer beneath Meshtastic and MeshCore. ## How it works LoRa uses **chirp spread spectrum** - the signal is spread across a wide frequency band using a continuously sweeping chirp tone. This spreading gives LoRa extraordinary resilience to noise. A receiver can decode a packet even when the signal is far below the background noise floor - a capability no conventional modulation scheme matches. ## Key characteristics - **Range:** 1 - 15 km typical; 30 - 50+ km achievable with elevated antennas - **Data rate:** 0.2 - 22 kbps depending on preset - slower than a 1990s modem, but sufficient for text and GPS - **Power:** Nodes run days to weeks on a small battery; 8 - 50 mA active depending on hardware - **No subscription:** Operates in the unlicensed 902 - 928 MHz ISM band in North America. No SIM, no carrier fees. - **License-free:** Standard operation under FCC Part 15.247 requires no amateur radio license ## What LoRa is NOT - **Not WiFi:** Far slower, far longer range. No web browsing or streaming. - **Not cellular:** No towers, no coverage maps, no subscription. Works anywhere two nodes are within radio range of each other. - **Not LoRaWAN:** LoRaWAN is a specific hub-and-spoke IoT architecture. Meshtastic and MeshCore are peer-to-peer mesh networks. Same radio hardware, completely different protocols. See the [LoRa Mesh vs. LoRaWAN](https://wiki.meshamerica.com/books/getting-started/page/lora-mesh-vs-lorawan) page for the full comparison. - **Not Bluetooth or Zigbee:** Those are short-range (meters). LoRa is long-range (kilometers). ## Why 915 MHz? The 902 - 928 MHz ISM band is the North American LoRa mesh standard because it is unlicensed under FCC Part 15, has better building and vegetation penetration than 2.4 GHz, has a low ambient noise floor, and yields practical antenna sizes (~8 cm quarter-wave). ## The fundamental tradeoff LoRa's extreme range comes at the cost of speed. A 50-byte text packet takes several hundred milliseconds to transmit. This is fine for messaging and GPS tracking - and impossible for voice, video, or large files. Design your use case around this constraint and LoRa delivers remarkable results. # LoRa Mesh vs. LoRaWAN Both use the same LoRa radio chips but operate completely differently. This is the most common source of newcomer confusion. ## LoRaWAN A **hub-and-spoke** network designed for IoT sensors reporting to the cloud. End devices transmit to fixed gateways; gateways forward over the internet to a server. No direct device-to-device communication. No gateway in range = no connectivity. Examples: The Things Network, Helium. ## LoRa Mesh (Meshtastic, MeshCore) A **peer-to-peer** network where nodes communicate directly and relay each other's messages. Works completely offline - no internet required. Messages hop: A → B (relay) → C → D. Adding nodes makes the network stronger. Examples: Meshtastic, MeshCore. ## Comparison table
FeatureLoRaWANLoRa Mesh
ArchitectureHub-and-spokePeer-to-peer
Internet requiredYesNo
Direct messagingNoYes
Multi-hop relayNoYes
Works without infrastructureNoYes
Typical use caseSensor data to cloudOff-grid comms, group coordination
**They cannot communicate with each other.** Different packet formats, addressing, and network stacks - they share hardware but speak different protocols. ## Important: LoRaWAN gateways won't build a mesh LoRaWAN gateways ($100 - $300) are one-way forwarders to the internet, not mesh relays. To build a LoRa mesh network you need Meshtastic- or MeshCore-compatible devices, not LoRaWAN gateways. # How Mesh Routing Works When two nodes are too far apart to communicate directly, intermediate nodes relay the message. Meshtastic and MeshCore solve this differently. ## Flooding (Meshtastic) When a node receives a packet, it rebroadcasts to all neighbors. Each node rebroadcasts once (duplicate detection prevents loops). The message floods outward until it reaches its destination or exhausts its hop count (typically 3 - 5 hops). - **Simple and robust:** No routing tables. New nodes work immediately. Self-healing if relay fails. - **Limitation:** One message can trigger 30 - 50 transmissions across a dense network. Why faster presets (Medium Slow) are preferred in networks with many nodes. ## Path-based routing (MeshCore) MeshCore discovers explicit routes before sending data: 1. Node A broadcasts a **path discovery packet**; each relay appends its identity 2. Destination node D sends back a **path acknowledgment** along the reverse path 3. Node A caches the route A → B → C → D and uses it for all subsequent messages to D - **More efficient at scale:** Messages travel only the established path - much less airtime than flooding in large networks - **Limitation:** Route discovery adds latency to first contact. Topology changes require re-discovery. ## Which is better? Both work well in practice. Flooding is simpler and more resilient for small-to-medium networks (under ~100 nodes). Path-based routing scales better for large infrastructure deployments. In practice, your choice is determined by which protocol your local community uses. ## The mesh advantage Every additional node is a potential relay. A hilltop repeater that can hear both a valley and a distant mountaintop effectively bridges those two coverage zones for all messages. A few well-placed infrastructure nodes have outsized impact on total network reach.