Can Humans Cause Radio Interference?

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Discussion Overview

The discussion revolves around the phenomenon of radio interference experienced by individuals when near their radio tuners. Participants explore whether humans can act as sources of radio interference and the mechanisms behind this effect, including concepts related to capacitance and radio wave transmission. The scope includes both theoretical considerations and personal experiences related to radio reception.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that humans can act as reflectors or secondary aerials for radio signals, potentially causing interference.
  • One participant mentions the possibility of shielding the tuner with materials like aluminum foil to mitigate interference.
  • Another participant states that while humans emit radiation at higher frequencies, they do not believe humans are the source of the interference.
  • There is a hypothesis that the human body could act as a capacitor, affecting radio signals, supported by anecdotal evidence of measuring voltage when touching an LED electrode.
  • Some participants propose that skin acids might act as a rectifier, converting radio frequency signals into direct current, contributing to the interference experienced.
  • A comparison is made to the operation of a Theremin, suggesting that proximity to the tuner could influence the signal similarly.
  • Questions are raised about why the tuner's antenna does not pick up external static if it exists, indicating confusion about the nature of the interference.

Areas of Agreement / Disagreement

Participants express a range of views on the causes of the interference, with no consensus reached. Some agree on the potential for human bodies to influence radio signals, while others question the mechanisms involved, leading to an unresolved discussion.

Contextual Notes

Participants mention various assumptions about the nature of radio waves, capacitance, and interference without fully resolving the underlying physics or providing definitive explanations.

porphyry5
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Are human beings radio wave transmitters? I recently moved to a new town and started listening to a new station on 101.9 fm. Found their broadcast plagued by static interference. Tried all the usual suspects, but it really looks like I am the source. When I approach the tuner the static increases, as I go away it decreases. Its not possible to put the tuner in another room, so is there some way I can shield the tuner from this effect? Thank you for your help.

Graham Lawrence
 
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You are acting as a reflector and secondary aerial for the static.

If you can work out where it is coming from you may be able to shield it somewhat with aluminium foil.

100 Megacycles gives a wavelength of 3 metres though so I wouldn't hold out too much hope.

Better to find the source of the interference and have it stopped - in most countries it's illegal to interfere with broadcast transmissions.

PS - Unless you are creating static electricity in huge quantities (nylon carpet?). In that case it should stop if you keep still
 
Same exact thing has been happening to me for years with the station I listen to after I bought a new radio (the old one didn't have the problem). I just can't approach my radio.

To answer your question, humans are radiation transmitters, but in much higher frequencies than a radio resonates at, so you are not the source of the cause. I don't know what causes this.
 
Just thinking out load (or however I should call it), couldn't it be that your body is creating some kind of capacitor and therefore messing with the signal. I've encountered this phenomenon in a funny way, when a LED was turning on with only one electrode connected and me (beleive me, I was insulated) touching the other. It was very dim but I could actually measure 1.4 volts across me! In a discussion with my friends we pretty much concluded that my body was acting as a coupling capacitor with the earth.
 
Sakha said:
Just thinking out load (or however I should call it), couldn't it be that your body is creating some kind of capacitor and therefore messing with the signal. I've encountered this phenomenon in a funny way, when a LED was turning on with only one electrode connected and me (beleive me, I was insulated) touching the other. It was very dim but I could actually measure 1.4 volts across me! In a discussion with my friends we pretty much concluded that my body was acting as a coupling capacitor with the earth.

Your were grounding it, creating a difference in potential.

But how would this effects a radio just by getting close to it?
 
Sakha said:
we pretty much concluded that my body was acting as a coupling capacitor with the earth.

It's more likely that you were simply picking up a local radio transmitter and the acids on your skin were acting as a crude rectifier with the metal contact to turn the RF signal into a dc voltage.

When I'm working with my Tesla coil I have to be really careful not to touch anything metal in my workshop because the powerful RF signal from the coil being picked up by my body is enough to create a fat spark a millimetre or two long and the shock I get from it is seriously unpleasant.
 
I want a Tesla coil :)
 
porphyry5 said:
I recently moved to a new town and started listening to a new station on 101.9 fm. Found their broadcast plagued by static interference. [...] When I approach the tuner the static increases, as I go away it decreases.

Perhaps you can gain some insight by reading about the operating principle of a Theremin. A Theremin is a music instrument that is designed to be sensitive to how close the hand is to the antenna. Pitch and volume are controlled by moving the hand closer to or away from the antennas for pitch and volume respectively.
 
AJ Bentley said:
It's more likely that you were simply picking up a local radio transmitter and the acids on your skin were acting as a crude rectifier with the metal contact to turn the RF signal into a dc voltage.

We concluded that I was acting as a capacitor because the phenomenon only happened if the LED electrode (either cathode or anode) was connected (respectively) to the output of an SMPS.
 
  • #10
AJ Bentley said:
You are acting as a reflector and secondary aerial for the static.

Thank you, but this confuses me. If there is an external source of static, why doesn't the tuner's own antenna pick it up along with the station signal?
 

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