[alancalverd]

I wonder if the animals develop tumours from the radioactive radiation in the exclusion zone. http://usukr-env.org/en/the-animals-in-chernobyls-radiation-zones-are-not-thriving-as-some-have-claimed-but-failing/ oops! it seems they might not be being hunted, but they do seem to have problems with tumours etc.   

Nothing new there, though the comparison with Fukushima is scientifically disgraceful.

Always worth reading the small print. Yes, animals in the zones of highest activity have the most defects. Just as expected and consistent with laboratory studies and the fact that other animals eat what they find locally whereas humans are likely to reject contaminated food and import clean stuff. There is a huge difference between ingesting long-lived radionuclides, particularly α-emitting "hot particles", and being exposed to external γ radiation

[Bored chemist]

the comparison with Fukushima is scientifically disgraceful.

Says the  man who said "Very little RF around Chernobyl".

It makes no real sense to try to compare RF which does not cause ionisation (and therefore chemical reactions), with nuclear radiation, which is ionising and does cause chemical change.

[alancalverd]

The Fukushima radioactivity release was probably 10% or less of that at Chernobyl, with substantially better containment of solid materials, and the resulting exclusion zone appears to be less than 10% of the area of the Chernobyl EZ. Interestingly, it seems that some 1600 people died in the Fukushima evacuation, far more than at Chernobyl (I don't have the figures to hand but IIRC it was less than 50).

On consideration I am inclined to retract "disgraceful" and replace it with "an order of magnitude inappropriate".

It was the original questioner, not I,  who implied that RF and nuclear radiation were sufficiently similar that his bedroom was comparable with the suburbs of Chernobyl.

[Bored chemist]

It was the original questioner, not I,  who implied that RF and nuclear radiation were sufficiently similar that his bedroom was comparable with the suburbs of Chernobyl.

I will take your word for it. There's a lot he said where I can't really tell WTF he means.
I had missed this bit earlier

I'm connecting the fabric to earth via a earth plug and wrist strap I have for fixing computers.

It depends where the resistor is, but, if it's near the plug then you have effectively connected an aerial to your cloth.

[vhfpmr]

You have a space in which there are multiple sources all coming from different directions, they then reflect off anything and everything creating multipath interference. Hanging up your conductive curtain serves to do little other than stir the pot, and reflect the signals in a different pattern. A bit like holding up a mirror in a room full of lamps: as fast as you cast a shadow from one lamp you reflect another.

Your detector won’t show this because it’s not selective, it’s measuring the total field and unable to see what’s going on with each source separately. Imagine a classroom full of schoolkids: it’s bedlam because they’re all sat rabbiting. You wonder where the din is coming from, so you take out a gag and place it on one of the kids. You hear no difference, so you take it off and try the next kid, then the next and the next. By the time you’ve been round the whole class you’ve come to the erroneous conclusion that the noise isn’t coming from any of them. What you need is the ability to listen to each one independently so that you can see what effect you’re having on each source one at a time, and in your room, that’s what a spectrum analyser does: you would see a forest of signals, and when you move the detector, or the large objects in the room, the amplitude of the signals would bounce up and down like yoyos.

Failing that, a gag that fits all the kids at once will do, that’s where the suggestion of aluminium foil on the walls comes in. Your problem though is creating a seal: no window, a continuous connection at the seams (including around the door), a sealed air vent, and last but not least, if you want power in the room you need filtering to stop signals being carried in on the power leads.

Or alternatively, you could just sit and wonder why you’re so bothered about it in the first place.

[LoneWolf (OP)]

CANCER

[alancalverd]

Since there is a 50% probability of anyone getting a natural cancer if they live long enough, it's probably not an efficient use of one's life to worry about it.

[LoneWolf (OP)]

Until you get it, which my girlfriend did. Thanks for everyone's input.

[Bored chemist]

Until you get it, which my girlfriend did. Thanks for everyone's input.

That rather misses the point that whatever caused the cancer almost certainly wasn't anything that a faraday cage would stop.

[alancalverd]

Nor would it be any use as a cure. There may be means of treating primary tumors and minimising metastasis, but apart from avoding the obvious carcinogens like smoking and industrial feedstocks, there isn't a lot you can do about cancer except to spot it early and treat it like any other disease when it happens. 

[Bored chemist]

avoding the obvious carcinogens like smoking and industrial feedstocks,  drinking alcohol and exposure to sunshine.

[alancalverd]

Benzene, toluene and xylene are labelled as carcinogenic, along with blue asbestos, aniline, beryllium, cadmium, dioxane, ethylene bromide.... NIOSH has a complete alphabet of stuff that we use to make other stuff, but prefer to keep inside glass  and steel tubing, not becuase it is acutely toxic but is definitely carcinogenic. Fortunately civilians rarely encounter any of them.

[Bored chemist]

Fortunately civilians rarely encounter any of them.

Which means that, for most people, they are not the "obvious carcinogens".
BTX are carcinogens, but are products, rather than feedstocks. Ditto aniline, dioxane, and dibromoethane.
Blue asbestos is practically banned.

So, you just don't come across them much.
The exceptions are BTX which are present in petrol.
But that's reasonable well controlled and they are poor carcinogens. Most people who use them don't get cancer from them.

Industrial pollution is probably a bigger factor.

[LoneWolf (OP)]

Can I re-ask this question.

I've got a electrostatic matt that I use to ground myself when fixing computers. If I put my tester onto it while it isn't grounded I get a readout of 0mV. When I attach the grounding wire to the earth plug I get a reading of ~80mV. Shouldn't it be the other way around? I asked an electrician who didn't understand it either.

[alancalverd]

Fortunately civilians rarely encounter any of them.

Which means that, for most people, they are not the "obvious carcinogens".
BTX are carcinogens, but are products, rather than feedstocks. Ditto aniline, dioxane, and dibromoethane.

Which means that, for most people, they are not the "obvious carcinogens".
BTX are carcinogens, but are products, rather than feedstocks. Ditto aniline, dioxane, and dibromoethane.
Blue asbestos is practically banned.

So, you just don't come across them much.
The exceptions are BTX which are present in petrol.
But that's reasonable well controlled and they are poor carcinogens. Most people who use them don't get cancer from them.

Industrial pollution is probably a bigger factor.

People are very rarely struck by lightning. I think we are arguing about the definition of "obvious"!  But it keeps the wits sharp.

[alancalverd]

Can I re-ask this question.

I've got a electrostatic matt that I use to ground myself when fixing computers. If I put my tester onto it while it isn't grounded I get a readout of 0mV. When I attach the grounding wire to the earth plug I get a reading of ~80mV. Shouldn't it be the other way around? I asked an electrician who didn't understand it either.

 Voltage is always "relative to..." You are trying to measure a potential difference. So the first question is what is the other end of your tester connected to?

Next question is 80 mV AC or DC?

And finally, what is the input impedance of your tester?

[LoneWolf (OP)]

The technical parameters of the detector are as follows:

Unit - V/m
Precision - 1V/m
Range - 1V/m- 1999V/m
Testing bandwidth - 5Hz--3500MHz

Its not connected to anything else, its just face down on the antistatic matt. Ive just tested it and im getting 261V/m

[alancalverd]

That's a lot of field strength. Need to think a bit.

[evan_au]

If I put my tester onto it while it isn't grounded I get a readout of 0mV. When I attach the grounding wire to the earth plug I get a reading of ~80mV.

I think you might be measuring 50Hz AC fields?

If the tester box is sitting on the electrostatic mat, the sensor within the box might be (say) 10mm from the electrostatic mat.
- If the mat is disconnected from the earth wire of your house, the mat and the tester will have effectively the same potential, and the reading will be 0 Volts/Meter (there may still be a magnetic field, as I understand it can detect both)
- If the mat is connected to the Earth wire in your house, the mat might carry an AC signal of (say) 2.6 Volts. Correct for the distance to the sensor (1/100 meters) and you could get a reading of 261 Volts/meter.

Precision - 1V/m...
I get a reading of ~80mV.

When you say "Precision", do you mean "Resolution"?
- If the Precision is 1V/m, then 80mV/m +/- 1V/m is still pretty close to zero (but depending on the design, it may still be a useful indication of relative field strength...)
- If the Resolution is 1V/m, then I don't see how it can report 80mV

These definitions can get a bit confusing, and I'm not sure I always get it right: https://en.wikipedia.org/wiki/Accuracy_and_precision

[alancalverd]

According to The Control of Electromagnetic Fields at Work Regulations 2016, a 50 Hz field strength exceeding 1.4 V V/m will produce a sensory effect and 170 V/m  is an "action level" in the MHz - GHz RF range. Health effects are likely at 10 V/m at low RF frequencies (below 10 MHz) The probability of anyone being  exposed at these levels in the home is very low indeed unless they are using a mobile phone.