Skip to content

Learn

Regulatory Deep-Dive: ISED Canada#

In Canada, the 902–928 MHz band is governed by RSS-210 (Issue 11, 2024) and RSS-247. While it is "license-exempt," it is not "law-exempt."

Key Compliance Factors#

  • Power Limits: For digital modulation (like LoRa), the maximum conducted power is 1 Watt (30 dBm). However, when using high-gain antennas, you must ensure your EIRP (Effective Isotropic Radiated Power) stays within legal limits to avoid interference with primary users like cellular providers or government radiolocation.
  • Frequency Hopping (FHS) vs. Digital Modulation: Meshtastic uses Frequency Hopping Spread Spectrum (FHSS). Under ISED rules, if your system hops across at least 25 non-overlapping channels, you are allowed the full 1-watt output. If you use a fixed frequency, you are restricted to much lower field strengths.
  • Encrypted Traffic: Unlike Amateur (HAM) radio—where encryption is strictly prohibited—the 915 MHz ISM band allows for full AES-256 encryption. This makes it the legal choice for private community security or tactical communication.

The LongFast Standard: Why It Matters#

US/LongFast – 906.875 MHz is the default modem preset for a reason, but it comes with a physical "cost" in terms of airtime.

Metric LongFast Value Why it matters
Bandwidth (BW) 250 kHz A wider pipe for data, but slightly less sensitive than 125 kHz.
Spreading Factor (SF) 11 Determines "chirp" length. High SF = longer range but massive airtime.
Coding Rate (CR) 4/5 Provides the error correction needed for weak signals.
Data Rate ~0.5 - 1.0 kbps Extremely slow. One text message can take 2–5 seconds of airtime.

The Hidden Danger of LongFast#

Because LongFast messages take several seconds to transmit, a busy mesh in a city like Toronto can quickly hit Channel Utilization limits.

  • Pro Tip: If your local mesh has more than 50 active nodes, consider encouraging the group to move to a Custom Preset with a narrower bandwidth (e.g., 62.5 kHz) to increase sensitivity and reduce collisions.

Meshtastic vs. MeshCore: Architectural Choice#

Choosing between these two is about Density vs. Mobility.

Meshtastic (Flood Routing)#

  • Mechanism: Every CLIENT node acts as a "dumb" repeater. When it hears a message, it waits a random interval and blasts it back out.
  • The Problem: In a dense city, 100 nodes might all try to repeat the same "Hello" message, creating a broadcast storm.
  • Best For: Ski hills, convoys, and ad-hoc emergency teams where nodes are constantly moving.

MeshCore (Infrastructure Routing)#

  • Mechanism: Uses a Client/Repeater hierarchy. Only "Repeaters" (infrastructure) handle the heavy lifting. "Companion" devices (your phone/radio) stay silent unless they are the source or destination.
  • The Advantage: Can support up to 64 hops, allowing a message to travel from downtown Montreal to the South Shore using only a few high-powered rooftop repeaters without "polluting" the local airwaves.
  • Best For: Municipal "backbone" networks and permanent smart-city sensors.

Community Standards & Etiquette#

To keep the 915 MHz band usable for everyone, Canadian meshers follow these unwritten rules:

  1. Telemetry Moderation: Do not set your "Position Broadcast" to every 60 seconds. In a mesh, once every 15-30 minutes is the gold standard.
  2. Mute Your Indoor Nodes: If you have an outdoor "Base" node on your roof, set your indoor handhelds to Client_Mute. This prevents your radios from fighting each other for the same airtime.
  3. Hop Limit Awareness: Never set your hop limit to 7 unless you are in the deep wilderness. In most Canadian cities, 3 hops is enough to cover the entire municipal area without causing unnecessary re-transmissions.