Bands & Frequencies
Unlicensed ISM and UNII bands let you transmit without an individual station license, but only within strict power, bandwidth, and duty-cycle boundaries. This is the master map of sub-1GHz through 6 GHz microwave spectrum used by wireless nodes.
US915 channel grid, EU868 duty-cycle tiers, Meshtastic preset frequency slots, and regional allocation gotchas.
1/2/4/8 MHz OFDM channelization, multi-megabit video range, 915 MHz coexistence with LoRa, and silicon modules.
Sub-1GHz home automation (868.4 / 908.4 MHz), 1-mile Z-Wave Long Range star topology, and Silicon Labs 800 hardware.
Interactive spectrum chart mapping real-time frequency collisions between Wi-Fi, Zigbee, Bluetooth, LoRa, HaLow, and Z-Wave across the 2.4 GHz and 915 MHz bands.
2.4 GHz channel planning (BLE/ESP-NOW), 5 GHz UNII tiers & DFS radar avoidance, and 6 GHz Wi-Fi 6E/7 AFC rules.
01 · The Master Spectrum Allocation
| Band | Frequency Range | Primary Region | Power / Duty Cycle |
|---|---|---|---|
| 433 MHz | 433.050 – 434.790 MHz | ITU Region 1 (EU/UK/Africa), Secondary in Region 2 (Americas) | 10 mW (10 dBm) in EU; FCC Part 15.231 in US • 10% in EU; periodic bursts only under Part 15.231 |
| 868 MHz | 863.000 – 870.000 MHz | ITU Region 1 (Europe, UK) | 25 mW (14 dBm) typical; up to 500 mW on 869.525 MHz • 0.1% to 10% depending on sub-band slice |
| 908 / 916 MHz | 908.400 – 920.000 MHz | ITU Region 2 (Americas, US/Canada) | ~0 dBm (Classic Mesh) to +30 dBm / 1 W (ZWLR Part 15.247) • Uncapped under FCC rules |
| 915 MHz | 902.000 – 928.000 MHz | ITU Region 2 (Americas, US/Canada/Latin America) | Up to 1 W (30 dBm) conducted with frequency hopping (FHSS) • No legal duty-cycle cap; governed by dwell time & bandwidth |
| 2.4 GHz | 2400.000 – 2483.500 MHz | Worldwide (Global ISM) | 100 mW (20 dBm) to 1 W depending on modulation • Uncapped worldwide |
| 5 GHz | 5150.000 – 5850.000 MHz | Worldwide (UNII-1 through UNII-3) | Up to 1 W (30 dBm) conducted on UNII-1/3, 250 mW (24 dBm) on UNII-2; DFS required on UNII-2 • Uncapped |
| 6 GHz | 5925.000 – 7125.000 MHz | Americas (FCC) & modern global adoptions | Low Power Indoor (LPI) up to 30 dBm EIRP; Standard Power requires AFC • Uncapped |
02 · Wireless Technology Breakdown
Wireless spectrum is not a one-size-fits-all medium. Depending on whether you need raw packet sniffing, home automation mesh, ten miles of range, or high-bandwidth video backhaul, the physical layer changes completely:
| Technology | Typical Hardware | Throughput | Real Range | Networking Layer |
|---|---|---|---|---|
| Classic FSK / OOK | TI CC1101 | 1.2 to 500 kbps | 100 – 500 m | Raw bytes / structs |
| Z-Wave / ZWLR (G.9959) | Silicon Labs ZG23 | 9.6 to 100 kbps | 30 – 100 m (Mesh) / 1.6 km (ZWLR) | Z-Wave frames / S2 security |
| LoRa (Chirp Spread Spectrum) | Semtech SX1262 | 0.3 to 22 kbps | 5 – 15+ km | Point-to-point / Mesh packets |
| Wi-Fi HaLow (802.11ah) | Morse Micro / Newracom | 150 kbps – 15+ Mbps | 1 – 3 km | Full TCP/IP, UDP, IPv6 |
| Microwave (2.4 / 5 / 6 GHz) | ESP32 / Wi-Fi 6/7 SoCs | 1 Mbps (BLE) to 40+ Gbps (Wi-Fi 7) | 10 – 100 m | TCP/IP, BLE GATT, Thread IPv6 |
03 · Propagation Physics & Antenna Cheat Sheet
Lower frequencies carry longer physical waves. That single physical rule determines how signals bend around hills, penetrate pine trees, and dictate the size of your antenna:
433 MHz (~69 cm)
Diffracts over ridge lines and cuts through wet woods. Requires larger antennas; difficult to fit into compact pocket enclosures.
868 / 915 MHz (~33 cm)
The sweet spot for wireless nodes. Quarter-wave antennas are only ~3.2 inches long. Good penetration through drywall and windows with strong reflection off metal.
2.4 GHz (~12.5 cm)
Tiny PCB trace antennas and high bandwidth. Easily absorbed by wet trees, human bodies, and concrete walls. Suffers 8 to 10 dB higher free-space path loss than 915 MHz.
5 GHz (~5.5 cm)
Extremely small antenna form factor. High attenuation through modern energy-efficient glass and masonry; excels at wide-channel line-of-sight backhauls.
6 GHz (~4.6 cm)
Ultra-compact antennas. Massive bandwidth (up to 320 MHz channels) but very high path loss. Primarily an in-room or line-of-sight technology.