Logging EMF instrument
Any of the above with unattended recording: required whenever the assessment depends on an average, a night-time value or a 95th percentile rather than a spot reading.
instrument dependent
Last verified 12 August 2026.
Also searched as: EMF logger, 24 hour logging meter
- Band covered
- instrument dependent
- Quantities measured
- magnetic flux density, power density, electric field strength
- Typical price
- $200–$3000
Detects
- Diurnal variation in power-line loading
- Night-time smart-meter and mesh traffic
- Intermittent sources that a spot survey misses entirely
Cannot detect
- Anything outside the host instrument's band
What to insist on
- Sample interval fast enough for pulsed sources, with peak capture per interval
- Exportable raw data, not just a summary screenshot
- Battery life covering the full logging window
Related records
- ELF magnetic field survey
A source-finding walkthrough plus a 24-hour log, because power-frequency magnetic fields track electrical load and a spot reading answers almost nothing.
Measurement protocols
- High-voltage transmission line
Fields directly beneath a loaded transmission line reach tens of milligauss and fall off roughly with distance for a balanced three-phase circuit, reaching background at 30–60 m for typical loadings.
Sources & emitters
Sources
- sbm-2024 Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024) — Institut für Baubiologie + Nachhaltigkeit (IBN), 2024. ngo, link checked 2026-08-12.
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