A reader emailed me that micro Teslas aren't technically a current measure, and a $40 tester might not be accurate. I responded with this:
"You're correct that Tesla isn't directly a current measure, but of magnetic fields, which are a function of currents. As I said, the specific math isn't important for this discussion, so I simplified it. EMF is a complex relationship between charged particles moving through electrical (E) and magnetic (M) fields (F), as described by Ampere and Maxwell and others. Currents are the particle motion that creates the fields.
Amazon has EMF detectors from $40 up to hundreds. The simple one I picked for this experiment is Chinese, so an American equivalent would probably be $100, if that makes you more comfortable. I wouldn't rely on it for precision work, but it seems adequate for determining relative risks of common devices at relatively low frequencies. This one is spec'd up to 3.5 GHz, though it probably varies in accuracy across that range. Exact measurements weren't my objective, just simple diagnostics. I don't expect a zero reading is actually zero, but is low enough to ignore. And I don't know the dose dependence of higher readings, so it's sufficient to recognize the high emitters and avoid them. Like watching the microwave oven by staring through the little window seems like a bad idea. It is interesting to walk around with it and see where the hot spots are. Often where you might not expect them.
For this discussion, the question is whether my sauna is risky or not. I'm satisfied it is not, and I'm probably a little more paranoid than average."
I didn't intend to provide a precise engineering analysis of my sauna, certainly not of saunas in general, only to decide whether my sauna seems to have the risks Dr Mercola described. It seems okay. There might be some risks from smaller fields than my simple tests can detect, such as the proliferation of 5G devices some people are becoming concerned about. There are a lot of risks we really can't do much about. It's always important to try to learn what matters, and what to do about it. Health is a complicated business.
Thanks - great information David - all of it. Please do keep us updated on the mysterious hot-spots in your house. That is very interesting!
A reader emailed me that micro Teslas aren't technically a current measure, and a $40 tester might not be accurate. I responded with this:
"You're correct that Tesla isn't directly a current measure, but of magnetic fields, which are a function of currents. As I said, the specific math isn't important for this discussion, so I simplified it. EMF is a complex relationship between charged particles moving through electrical (E) and magnetic (M) fields (F), as described by Ampere and Maxwell and others. Currents are the particle motion that creates the fields.
Amazon has EMF detectors from $40 up to hundreds. The simple one I picked for this experiment is Chinese, so an American equivalent would probably be $100, if that makes you more comfortable. I wouldn't rely on it for precision work, but it seems adequate for determining relative risks of common devices at relatively low frequencies. This one is spec'd up to 3.5 GHz, though it probably varies in accuracy across that range. Exact measurements weren't my objective, just simple diagnostics. I don't expect a zero reading is actually zero, but is low enough to ignore. And I don't know the dose dependence of higher readings, so it's sufficient to recognize the high emitters and avoid them. Like watching the microwave oven by staring through the little window seems like a bad idea. It is interesting to walk around with it and see where the hot spots are. Often where you might not expect them.
For this discussion, the question is whether my sauna is risky or not. I'm satisfied it is not, and I'm probably a little more paranoid than average."
I didn't intend to provide a precise engineering analysis of my sauna, certainly not of saunas in general, only to decide whether my sauna seems to have the risks Dr Mercola described. It seems okay. There might be some risks from smaller fields than my simple tests can detect, such as the proliferation of 5G devices some people are becoming concerned about. There are a lot of risks we really can't do much about. It's always important to try to learn what matters, and what to do about it. Health is a complicated business.