When do you start feeling radio signals

[Brownhunter]

Hi there!

I have just recently been getting interested in the whole EMF spectrum of late but something suddenly made me curious.

How strong does a radio frequency has to be in megahertz for you to feel it?

Any assistance would be appreciated.

 

[solderdude]

That depends on the wavelength (frequency)
It could 'register' as heat.
This isn't strange as it is power.

As far as I know people who claim to be affected by RF signals have never been able to prove this in controlled tests even at almost unsafe levels.

of course there is still a lot of debate about long term exposure to radio waves and the importance of the frequency.
I will bet if you look at research done for the industry it will show no influence.
When the research is done for anti-this or that chances are the outcome is inconclusive and more research is needed.

Experimenting on humans is a bit controversial though.

 

[gene_stl]

I have read (in the 1960s) that it was possible/theorized that fillings in teeth could act like the germanium diode in a crystal radio and if the individual were in an RF field it might cause a sensation or feeling of the demodulated signal. Seems unlikely but might be possible.

 

[mhardy6647]

I have read (in the 1960s) that it was possible/theorized that fillings in teeth could act like the germanium diode in a crystal radio and if the individual were in an RF field it might cause a sensation or feeling of the demodulated signal. Seems unlikely but might be possible.

It used to happen with amalgam fillings. Folks thought they were going crazy.

Here's (almost!) a corollary: When I was a kid, my parents (OK, my father, first and foremost) had a hifi system that used a (somewhat mismatched) pair of high-sensitivity EV "Wolverine" fullrange (twincone) drivers in large vented enclosures. I remember vividly hearing one of them (an LS-15 driver; sensitivity in the mid-high 90s dB per watt @ 1 meter) playing a local AM radio station (WFBR) faintly but unmistakably, with everything in the system switched off. WFBR's transmitters were just a few miles from our house. My father's theory was that the (long) speaker wire on the LS-15 was doin' the work of an antenna, and something (maybe a defect in the voicecoil, or maybe just the screw-threaded junction 'twixt wire & driver) was acting as a detector.

Irrespective of the root cause, that speaker could play WFBR sans electricity -- akin to a "foxhole radio" (look it up)

EDIT: These are LS-15 'fullrange' drivers, FWIW.

P1030332 by Mark Hardy, on Flickr

P1030335 by Mark Hardy, on Flickr

 

[Mnyb]

Is not possible to feel TV transmitters if you climb the towers (not recommended activity ). because both high frequency and high power like 100kW's

 

[solderdude]

You probably cannot get near antennae in such transmitting towers without having turned off the transmitters or dampers applied.
The effect would be similar as being inside a microwave.
You will get cooked alive.

 

[Mnyb]

You probably cannot get near antennae in such transmitting towers without having turned off the transmitters or dampers applied.
The effect would be similar as being inside a microwave.
You will get cooked alive.

I don't know which frequencies you need to reach to get microwave like effects (excepts of course the frequencies microwaves operates at ), your microwave probably uses the most efficient frequencies for the purpose. But i suppose other frequencies will do given the power levels involved and if there is a physical phenomena that can deposit energy inside you

Radar is said to have similar effects close up.

In my line of work we had a strange issue where as set of big industrial VSD drive systems where knocked out by boat radar from a nearby shipping canal, we could tie the fault occurrence to the shipping schedule from the mill, it always happened on the same weekday at roughly the same hour of the day .

 

[solderdude]

radar and microwave frequencies are in the same band.

I thought exposure limits are around 0.1 W/kg so 9W for the average male would be acceptable. There is a safety margin of 50x so 1kW of RF (regardless of frequency) would be considered dangerous.

It's a bit more complex though and country dependent as well.

 

[mhardy6647]

The radar and microwave ovens have an inextricably intertwined history -- that also involves WWII and death rays.


https://www.newenglandhistoricalsoc...r-melts-chocolate-bar-invents-microwave-oven/
https://www.bbc.com/news/business-41188464

 

[JeffS7444]

The ability for microwaves (~2.4 ghz transmissions) to heat up stuff was known long before microwave ovens became popular, hence brand names like Amana's "Radar Range". But the intensity of your exposure falls rapidly with distance per the Inverse Square Law.

 

[LarsS]

Mid 90’s I had this Nokia 8110 cellphone, my office in central Stockholm was located some ~25meters from the mobile antenna.
Fractions of a second (or something like that) before my phone rang I could sense what I’d describe as a slight thump in my head. I proved this several times for colleagues in somewhat controlled experiments.
Switched cellphone to a low radiation Ericsson.