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Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 4:46 pm
by cab1
which definitely has been proven in "Better Call Saul" ;-)

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 6:36 pm
by W. H. Heydt
cab1 wrote:
Wed Mar 28, 2018 4:46 pm
which definitely has been proven in "Better Call Saul" ;-)
Would please quote the post you're referring to? By itself, it is difficult or impossible to determine which comment you are referring to.

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 6:40 pm
by W. H. Heydt
cab1 wrote:
Wed Mar 28, 2018 4:20 pm
at a different frequency
While that is true, if you are not objecting to 50/60 cycle EM radiation, you have just "moved the goal posts". In terms of radiated power, this is the greatest amount of *artificial* radiation you're going to be exposed to, except for lighting.

Really...I suggest starting with a good course in Physics.

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 6:40 pm
by cab1
W. H. Heydt wrote:
Wed Mar 28, 2018 6:36 pm
cab1 wrote:
Wed Mar 28, 2018 4:46 pm
which definitely has been proven in "Better Call Saul" ;-)
Would please quote the post you're referring to? By itself, it is difficult or impossible to determine which comment you are referring to.
In the film I mentioned there was a guy who did what you mentioned concerning aluminum foil...
(just a joke since it didnt help him)

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 7:30 pm
by solar3000
I emit infrared radiation.

One time I placed my phone in aluminum foil, then plastic sandwich bag. Then aluminum, then plastic. and all of that in a waterproof die cast aluminum case. then all of that under water in a cast iron bath tub.
It still transmits data. GPS was dead. So was bluetooth and wifi. but cellular was still connected.
go figure.

15 years ago, I placed my phone inside a sandwich bag and then under water. the signal was completely gone.

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 9:03 pm
by cab1
W. H. Heydt wrote:
Wed Mar 28, 2018 6:40 pm
cab1 wrote:
Wed Mar 28, 2018 4:20 pm
at a different frequency
While that is true, if you are not objecting to 50/60 cycle EM radiation, you have just "moved the goal posts". In terms of radiated power, this is the greatest amount of *artificial* radiation you're going to be exposed to, except for lighting.

Really...I suggest starting with a good course in Physics.
Radiation energy (significantly) depends on the frequency. Thus, 50 Hz should have a "slightly different" physical effect than 50.000.000.000 Hz of a wifi client. Additionally, the "amount" of the effect on the human body strongly relates to the absorption capability of a certain frequency by biological cells. Whereas the first is quite understood, the second isnt. Nevertheless, I can not see any reason to absolve wifi radiaton from influencing my health just because living between a set of wires and sockets in my home didnt kill me up to now.

Sorry if my explanations dont meet your demands concerning physics ... really.

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 9:37 pm
by Heater
cab1,
Nevertheless, I can not see any reason to absolve wifi radiaton from influencing my health just because living between a set of wires and sockets in my home didnt kill me up to now
I suspect, you are far more likely to be killed by the 50Hz mains power supply to your home than any number of WiFi gadgets you are likely to have at home. At least there is evidence of mains power killing people whereas there is none for WiFi waves.

There are so many other more significant life threatening risks to think about.

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 10:20 pm
by W. H. Heydt
cab1 wrote:
Wed Mar 28, 2018 9:03 pm
50.000.000.000 Hz of a wifi client.
One too many zeros.

Really....the bigger radiation danger is gamma emission from naturally occurring nucleides that are already *inside* your cells. Biggest risk is almost certainly the beta emission from K40 incorporated into biological molecules, and the recoil from beta emission of C14. The signals you're concerned about are completely trivial next to those issues...and you can't do *anything* about the K40 and C14.

Re: pi3: how to avoid "any" radiation?

Posted: Wed Mar 28, 2018 10:28 pm
by Heater

Re: pi3: how to avoid "any" radiation?

Posted: Thu Mar 29, 2018 11:52 am
by hippy
Whether the OP is 'talking out their backside', worrying over nothing, should be more worried about something else, isn't really relevant to the technical issue of eliminating or minimising whatever emission does come out of a Pi.

Discussions and refutation of a poster's personal beliefs would be best done elsewhere more suited to that.

Re: pi3: how to avoid "any" radiation?

Posted: Thu Mar 29, 2018 12:55 pm
by jahboater
Make the whole house into a faraday cage :)

As for 50Hz em radiation, the wiring in the house is so short compared to the wavelength (which is nearly 6km) that I doubt it would radiate effectively.

Re: pi3: how to avoid "any" radiation?

Posted: Thu Mar 29, 2018 1:14 pm
by PeterO
jahboater wrote:
Thu Mar 29, 2018 12:55 pm
Make the whole house into a faraday cage :)

As for 50Hz em radiation, the wiring in the house is so short compared to the wavelength (which is nearly 6km) that I doubt it would radiate effectively.
λ = v/f
3E8 m/s / 50 Hz = 6E6 m (6000km)
PeterO

Re: pi3: how to avoid "any" radiation?

Posted: Thu Mar 29, 2018 1:25 pm
by jahboater
PeterO wrote:
Thu Mar 29, 2018 1:14 pm
jahboater wrote:
Thu Mar 29, 2018 12:55 pm
Make the whole house into a faraday cage :)

As for 50Hz em radiation, the wiring in the house is so short compared to the wavelength (which is nearly 6km) that I doubt it would radiate effectively.
λ = v/f
3E8 m/s / 50 Hz = 6E6 m (6000km)
PeterO
Ah yes!

With a 6000km wavelength, how much will a few metres of house wiring radiate ?

Re: pi3: how to avoid "any" radiation?

Posted: Thu Mar 29, 2018 1:48 pm
by karrika
If you are really into low radiation devices then have a look at small microcontrollers that can turn themselves off to a sleep mode.
I would also suggest looking into very low power chips. Arduino comes to mind...

The best design does not produce electric noise at all. But creating a noiseless design is art. Just putting chips on a board and using spread spectrum tricks to pass tests is far too common today.

Re: pi3: how to avoid "any" radiation?

Posted: Thu Mar 29, 2018 3:10 pm
by droleary
hippy wrote:
Thu Mar 29, 2018 11:52 am
Whether the OP is 'talking out their backside', worrying over nothing, should be more worried about something else, isn't really relevant to the technical issue of eliminating or minimising whatever emission does come out of a Pi.
If it's an actual technical issue, the OP should be interested in measuring the radiation that surrounds them rather that focusing on a single low-powered device like the RPi. Anything else is a premature optimization. Like I said, the odds are pretty good that radiation in the visible spectrum is the main "threat". Anything towards the UV side is going to be the most dangerous, and anything down into IR and microwave (outside of an oven) is going to be a minor issue. The impact of radio waves will likely be negligible.

Re: pi3: how to avoid "any" radiation?

Posted: Thu Mar 29, 2018 4:13 pm
by jamesh
What Hippy said - please keep to the topic in hand.

Re: pi3: how to avoid "any" radiation?

Posted: Tue Apr 03, 2018 7:08 am
by ejolson
hippy wrote:
Thu Mar 29, 2018 11:52 am
relevant to the technical issue of eliminating or minimising whatever emission does come out of a Pi.
It would seem the rfkill command can be used to turn off WiFi and the Bluetooth devices. If the Pi is running headless, how do you turn off HDMI? Does reducing the clock speed reduce radiation? Is there anything else?

Re: pi3: how to avoid "any" radiation?

Posted: Tue Apr 03, 2018 7:18 am
by jahboater
ejolson wrote:
Tue Apr 03, 2018 7:08 am
If the Pi is running headless, how do you turn off HDMI?
Do you mean:

$ tvservice --off
Powering off HDMI

Re: pi3: how to avoid "any" radiation?

Posted: Tue Apr 03, 2018 7:22 am
by mikerr
Turn off hdmi (until reboot)

Code: Select all

tvservice -o
Turn off BT and Wifi (permanently):

Code: Select all

sudo rfkill block all