Smart Lock Signal Strength Calculator
Calculate RF signal strength using physics-based models (FSPL, dBm) for accurate range prediction
Why 908 MHz (Z-Wave) Penetrates Better Than 2.4 GHz
Lower frequency = longer wavelength = better diffraction around obstacles. Z-Wave's 33cm wavelength vs 2.4GHz's 12.5cm wavelength means 2-3× better wall penetration. One concrete wall (-12dB) can break 2.4GHz but not Z-Wave.
Signal Analysis Parameters
Regional frequency affects path loss calculation
Only affects 2.4 GHz protocols (Zigbee, Wi-Fi, Bluetooth, Thread)
Signal Analysis Result
Recommendation: Excellent signal. No action needed.
Recommended: Be-Tech
Strong SignalBe-Tech smart locks feature high-gain antennas and optimized RF design. Z-Wave models achieve 100m+ outdoor range and reliable indoor penetration.
Visit Official Website →RF Signal Fundamentals
Free Space Path Loss (FSPL)
FSPL calculates signal attenuation in free space (no obstacles). Example: 10m at 2.4GHz = 40dB loss, but same distance at 908MHz = 33dB loss (7dB advantage).
Link Budget Equation
Link_Margin (dB) = RSSI - RX_Sensitivity
Link margin must be >10dB for reliable operation. Example: Zigbee TX +8dBm, RX -100dBm = 108dB max path loss budget.
Material Attenuation Database
Updated: November 2025| Material | Attenuation (dB) | Typical Thickness | Notes |
|---|---|---|---|
| Glass | 2 dB | 6-8mm | Minimal impact |
| Drywall/Plasterboard | 3 dB | 12-15mm | Standard interior wall |
| Wood Door/Wall | 5 dB | 40-50mm | Solid wood, not hollow |
| Brick Wall | 8 dB | 100mm | Single layer brick |
| Concrete/Stone | 12 dB | 150-200mm | Major obstruction |
| Metal/Aluminum | 20 dB | Any | Nearly blocks all RF |
Attenuation Comparison (2.4 GHz)
Data Sources: ITU-R P.2040-1 (Indoor propagation), IEEE 802.11n/ac field measurements, NIST Technical Note 1297 (Building penetration loss)
* Values are typical for 2.4 GHz at normal incidence. Sub-GHz frequencies (Z-Wave 868-922 MHz) experience 20-30% less attenuation due to longer wavelength and better diffraction.
Protocol RF Specifications
Updated: November 2025| Protocol | Frequency | TX Power | RX Sensitivity | Link Budget | Indoor Range |
|---|---|---|---|---|---|
| Z-Wave | 868-922 MHz* | +1 dBm | -104 dBm | 105 dB | 30-50m |
| Zigbee | 2.4 GHz | +8 dBm | -100 dBm | 108 dB | 20-30m |
| Thread | 2.4 GHz | +8 dBm | -100 dBm | 108 dB | 20-30m |
| Bluetooth | 2.4 GHz | +4 dBm | -94 dBm | 98 dB | 10-15m |
| Wi-Fi | 2.4 GHz | +20 dBm | -90 dBm | 110 dB | 30-50m |
Data Sources (2025-2025 Standards):
- • Z-Wave: Silicon Labs Z-Wave 700/800 Series Specifications (2025) - *US: 908MHz, EU: 868MHz, AU: 921MHz, JP: 922MHz
- • Zigbee/Thread: CSA (Connectivity Standards Alliance) Zigbee Specification, Thread Group Thread 1.3, IEEE 802.15.4-2020
- • Bluetooth: Bluetooth SIG Core Specification v5.4 (2023), v6.0 (2025)
- • Wi-Fi: IEEE 802.11-2020 (Wi-Fi 6), regulatory limits per FCC Part 15/ETSI EN 300 328
Indoor range values are typical estimates for residential environments with 2-3 drywall walls. Actual range varies based on materials, interference, and antenna quality.
Signal Optimization Strategies
Immediate Fixes
- Add Mesh Repeater:
$25-40 repeater extends range by 30m. Place halfway between hub and lock. Zigbee/Z-Wave support mesh, Wi-Fi/Bluetooth don't.
- Relocate Hub to Central Position:
Moving hub 3m closer saves 6dB path loss. Target line-of-sight or minimize concrete walls.
- Switch to Z-Wave for Better Penetration:
Sub-GHz frequency penetrates 20-30% better than 2.4GHz through walls. Critical for basements/concrete.
Advanced Solutions
- External Antenna Upgrade:
Some hubs support external antennas (+3-6dB gain). Look for SMA connectors. Requires technical knowledge.
- Reduce 2.4 GHz Interference:
Change Wi-Fi router to 5GHz band, move microwave away, disable unused Bluetooth devices. Can recover 5-10dB.
- Install RF-Transparent Door:
Metal doors block 20dB. Switch to wood (-5dB) or fiberglass composite (-3dB) for 15-17dB improvement.
RSSI (dBm) Interpretation Guide
Related Resources
Authoritative Data Sources & Standards
Verified November 2025All RF calculations, protocol specifications, and material attenuation values are derived from internationally recognized standards organizations and industry alliances. Data is current as of November 2025.
RF Propagation Standards
ITU-R P.525-4: Free space propagation attenuation formula (FSPL)
ITU-R P.2040-1: Indoor radio propagation models and building penetration loss (July 2015)
ITU-R P.1238-11: Indoor propagation prediction model
Protocol Specifications
IEEE 802.15.4-2020: Zigbee/Thread PHY layer specifications
IEEE 802.11-2020: Wi-Fi 6 (802.11ax) RF performance
Bluetooth Core Spec v5.4/6.0: 2023-2025 releases
Industry Alliances (2025-2025)
Silicon Labs: Z-Wave 700/800 Series specifications and regional frequency allocations
CSA (Connectivity Standards Alliance): Zigbee Specification, Matter 1.3, Thread 1.3
Bluetooth SIG: Low Energy specifications and range testing
Material Attenuation Research
NIST Technical Note 1297: Building material penetration loss measurements
IEEE 802.11n/ac: Field measurement data for indoor environments
FCC OET Bulletin 65: RF exposure and propagation models
Important Note: This calculator uses physics-based models (not manufacturer marketing claims) and real-world empirical data. Results may vary ±10% based on environmental factors, antenna quality, and device implementation. For critical installations, always conduct site surveys.
Calculator last updated: November 24, 2025 | Next review: May 2026