Do multiple WiFi devices create areas of high EMR?

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Discussion Overview

The discussion revolves around the potential effects of multiple WiFi devices in a typical house or office setting, specifically focusing on whether areas of high electromagnetic radiation (EMR) could be created due to constructive interference among the devices. The scope includes theoretical considerations of interference patterns and safety levels associated with EMR exposure.

Discussion Character

  • Exploratory, Debate/contested, Technical explanation

Main Points Raised

  • Some participants propose that in environments with multiple WiFi devices, areas of constructive interference could aggregate the electromagnetic fields, potentially exceeding safe power levels for individual devices.
  • Others argue that the non-stationary nature of the devices means that interference patterns will not remain fixed in one location, suggesting that concerns about high EMR levels may be overstated.
  • One participant suggests that for modeling exposure, it may be safest to assume that the fields from multiple devices are additive, leading to the possibility of exceeding safety levels.
  • Another participant counters that commercial home and office devices operate at power levels significantly below safety limits, indicating that the cumulative exposure is unlikely to be a concern.
  • It is noted that the oscillators in the devices are not phase locked, which would result in a random interference pattern rather than consistent peaks of EMR.

Areas of Agreement / Disagreement

Participants express differing views on the implications of multiple WiFi devices creating areas of high EMR. While some raise concerns about cumulative exposure, others downplay these worries, leading to an unresolved discussion regarding the actual risks involved.

Contextual Notes

There are assumptions regarding the additive nature of electromagnetic fields and the operational power levels of WiFi devices that remain unverified. The discussion also hinges on the behavior of non-stationary sources and their interference patterns, which may not be fully explored.

ChrisXenon
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TL;DR
Do they constructively interfere to create local high spots?
I'm thinking in a typical house or office, areas of constructive interference may exist which aggregate the fields of maybe 10 WiFi devices.
Wouldn't this mean the safe power levels stipulated for any single device would be routinely be exceeded? And if so, do we care?
 
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They are not stationary, so interference will never sit still in one spot.

The simpler answer, is don't worry.
 
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ChrisXenon said:
I'm thinking in a typical house or office, areas of constructive interference may exist which aggregate the fields of maybe 10 WiFi devices.
Sure. When modeling the exposure, the safest assumption would be to assume they are additive (always constructively interfering).
Wouldn't this mean the safe power levels stipulated for any single device would be routinely be exceeded? And if so, do we care?
No. Commercal home/office devices don't operate at power levels anywhere close to the limits. They are several orders of magnitude too weak:
https://www.fcc.gov/general/radio-frequency-safety-0
 
anorlunda said:
They are not stationary,
Moreover, the oscillators in all the devices are not phase locked so the resulting phasor addition of a number of sources will only ever give you a random-looking product with an RMS value that's the sum of the source waves; no identifiable peaks and troughs, (un?)fortunately.
 
Excellent - thank you both.
 

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