315 MHz Band Overview

The 315 MHz frequency is part of the UHF (Ultra High Frequency) band and is widely used for low-power, short-range wireless communication in the Americas and parts of Asia. Known for its excellent penetration and low interference potential, 315 MHz is a cornerstone of keyless entry systems, remote controls, and unlicensed IoT applications.

It is especially favored in ITU Region 2 (🌎), where it’s allocated for license-exempt use under specific technical constraints.

Table of Contents

📶 Frequency Range

Center Frequency: 315 MHz
Common Operating Band: 314–316 MHz
Band Class: UHF
ITU Allocation: Region 2 focus (Americas)

🌍 Regional Use Breakdown

🌐 Region	Frequency Allocation	Primary Use	Licensing
🌎 Region 2	314–316 MHz	Remote keyless entry, garage doors, IoT	License-exempt (FCC Part 15)
🌍 Region 1	Not standardized	Rare use; 433 MHz preferred	Often unallocated
🌏 Region 3	Some usage in Japan and Korea	Similar to Region 2	Conditional licensing

📱 Applications and Use Cases

Application	Description
Keyless Entry Systems	Vehicle fobs and door locks commonly use 315 MHz in the Americas
Garage Door Openers	Popular due to minimal interference and reliable propagation
Remote Controls	Consumer and industrial remotes for lighting, gates, etc.
Short-Range IoT Devices	Environmental sensors, alarms, asset tracking
Industrial Automation	Conveyor controls, motorized blinds, and smart actuators

🔐 Licensing & Access

Region 2 (FCC Part 15):
- License-exempt under Part 15.231, with limitations on duty cycle and bandwidth
- Max ERP: typically 10–50 mW depending on modulation
- Must not cause harmful interference and accept any received interference
Outside Region 2:
- Usage is limited or disallowed; 433 MHz often takes its place

⚡ Technical Specs

Parameter	Typical Values
Max Power (ERP)	10–50 mW (license-exempt)
Modulation	ASK, FSK, OOK
Bandwidth	10–20 kHz typical
Range	~100 m line-of-sight; 10–30 m indoors
Antenna Size	~23–24 cm quarter-wave monopole

📊 Regulatory Overview

Regulation	Details
FCC Part 15.231	Governs periodic transmissions, low-power RF controls
IC RSS-210	Canadian equivalent for unlicensed low-power devices
Japan ARIB STD-T107	Covers SRDs using similar bands in Japan

📡 Adjacent Bands and Related Use

Band	Frequency Range	Use
260–290 MHz	Military, meteorology (radiosondes)
300–322 MHz	Partially reserved; radar, ISM in some countries
315 MHz	SRDs: keyless entry, IoT (Region 2)
400–470 MHz	Land mobile, amateur, LPWAN, ISM (433/450 MHz popular)

🔁 Spectrum Sharing & Interference

315 MHz is less congested than 433 MHz, especially in the U.S.
Reduced co-channel interference due to narrower adoption
Can suffer interference in dense urban deployments or industrial zones
Devices must limit on-time and emissions to minimize cross-talk

🛰️ Engineering Notes

Propagation is better than 433 MHz indoors due to slightly lower frequency
Common in automotive-grade transceivers (e.g., TI, Microchip, NXP)
Lower antenna size vs. 433 MHz (~23 cm vs 17 cm for ¼ wave)
Some SRDs switch between 315/433 for regional compliance

🧠 Summary Table

Attribute	Value/Details
Center Frequency	315 MHz
ITU Region Focus	Region 2 (Americas)
Primary Use	Keyless entry, remote control, IoT
License Required?	No (Part 15-compliant)
Typical Power	10–50 mW ERP
Modulation	ASK, FSK, OOK
Band Status	License-exempt, narrowband
Common Chipsets	CC1101, MICRF112, ATA5724, etc.