Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Test Microwave for Radiation Leakage

ismymicrowaveleaking.isotropic.us

Post reply on HN
Print view View original

81–90 of 110 posts

Re: Test Microwave for Radiation Leakage

#81

Post by NikolaNovak »

larsrc wrote: post #8

Isn't it lovely how we're inundating our homes with radiation at wavelengths that can cook meat? It's as if we _want_ the robot revolution to succeed.

I hear these concerns in real life and as per my longer post above, I don't understand the threat model. My oven and stove can also cook meat. It's what they do. What is the actual concern? I feel I have burned myself on ovens and stoves a lot more than I have on microwaves in my life (let alone the risks in popular gas stoves etc). I am genuinely curious what is the delta and differentiating factor making microwaved mystically scary?

Re: Test Microwave for Radiation Leakage

#82

Post by manwe150 »

NikolaNovak wrote: post #80
KennyBlanken wrote: post #37

Earlier quoted context omitted.

> I remain in awe that we trust the very cheapest plastic under repeat load and thermal cycling to form a -40dB seal, turning 700W into 70mW It's the metal grid in the window (with holes smaller than the wavelength of the microwaves), and the metal shell of the cavity, not any "plastic." The same reason the metal grid works is why there doesn't need to be a perfect door seal. As long as as the gap is smaller than the…

Am I wrong in ignorant understanding that if some radiation leaked, its' effect would largely be about heating affected body parts, which presumably you'd feel as, you know, heat; as opposed to some magical or teryfing "thing"? In other words, why is microwave leaking worse than e. G. My oven leaking heat? Is potential small amount of microwave radiation In some specific way worse than feeling the heat when you open…

IR radiation is stopped very easily, eg by dead skin cells. Higher energy radiation, eg microwaves, can penetrate much deeper into your body and start causing damage to living tissues.

Re: Test Microwave for Radiation Leakage

#83

Post by fy20 »

aimor wrote: post #58

An alternative method: build a LEctenna. https://www.nrl.navy.mil/STEM/LEctenna-Challenge/ I stumbled across this little project a few weeks back, ordered the parts (just a diode and an led), and it works. Put a bowl of water in the microwave (or dinner), turn it on, then wave the lectenna around the cracks and see where it lights up. I originally found the lectenna by researching if it was possible to power an LED w…

If you run a low voltage 24V DC power cable for lighting next to a 220V AC line (I'm in Europe, no idea if 120V does the same) it's quite easy to get a situation where there is enough power for LED lights to be lit even when switched off. This is why low voltage wiring (lighting, ethernet, hdmi, etc) should not be ran parallel to AC power cables.

Re: Test Microwave for Radiation Leakage

#85

Post by fmasood »

femto wrote: post #66

Neat idea, though it's not a definitive test. In my experience a microwave oven cavity provides about 40dB attenuation, and it's possible to maintain an LTE connection with that sort of path loss. Hint: If you're ever doing radio work in the field and need an instant Faraday cage a microwave oven is a good candidate. Turn the power off first to reduce the risk of accidentally irradiating your device, but leave it plu…

Depending on your region, LTE could be using much higher frequencies. Microwave ovens use a fixed frequency and the cage is designed for that. Considering this I would say it's still an effective test.

Re: Test Microwave for Radiation Leakage

#86

Post by zdragnar »

O5vYtytb wrote: post #70
hanoz wrote: post #63

This was one of my first app ideas about 10 years ago. Unfortunately my microwave had a mechanical timer such that if you opened the door when it was running the microwaving would stop, and on closing again it would resume. Unbeknown to me the door had been so opened, and on closing, with my HTC Desire inside, it duely resumed.

thats an awful feature

It is pretty convenient as long as you aren't putting cell phones into it.

Re: Test Microwave for Radiation Leakage

#87

Post by ganzuul »

eyelidlessness wrote: post #65
ganzuul wrote: post #29

Earlier quoted context omitted.

You need a basic level of competence to be allowed in the kitchen. - That is where most domestic accidents happen. Funny how kitchen stuff was thought to be women's work once.

I have read this several times over and have no idea how you could mean it which isn’t sexist af. Edit: okay maybe I can imagine you’re saying that women have been competent in the kitchen and men [/other gender identifying people?] have demonstrated not being as competent. I’m really trying to stretch credulity to read this in good faith.

Women are widely known to be more attentive and dexterous in e.g. electronics assembly. Surely this translates to the domestic kitchen as well.

Sexist? Please, shove that word. This is simple facts about life.

Re: Test Microwave for Radiation Leakage

#88

Post by ganzuul »

dhdc wrote: post #56
ganzuul wrote: post #52

Earlier quoted context omitted.

The specific scenario I have in mind is a student living on their own for the first time, cooking with a microwave in their room. Many catastrophic fuckups that we were quick to forget took place during this phase in life. You might take apart a microwave oven and discover that there are actually several pieces of sheet metal in them. Expensive ones connect them by staked wires. The capacitor is usually rated for 200…

How does a student living on their own has to do with anything about microwaves having "lethal potentials"? And what does the high-voltage capacitor has to do with sheet metals? I'm sorry, but I really cannot follow your logic here.

Have you ever looked inside a very dirty computer? It's quite simple.

Re: Test Microwave for Radiation Leakage

#89

Post by ganzuul »

Retric wrote: post #57
dhdc wrote: post #48

Earlier quoted context omitted.

The point of a microwave to have a faraday cage is not for preventing interference with wifi; the cage is there for preventing the microwave microwaving the user. At an average power of 1000W, even a thousand-fold attenuation (-30dB) means 1 watt/30dBm leaks out, minuscule for humans but enough to saturate typical wifi receivers.

The cage was originally there to make them more efficient, spraying microwaves into the room would mean you food takes a lot longer to cook. Anyway, I don’t recall all the details but 1W from a microwave is probably an underestimate. WiFi uses multiple separate frequencies and outside of what a microwave should be producing. So it’s significantly more energy to block it than you might think especially when the hub is…

> A Federal standard (21 CFR 1030.10) limits the amount of microwaves that can leak from an oven throughout its lifetime to 5 milliwatts (mW) of microwave radiation per square centimeter at approximately 2 inches from the oven surface.

So you were off by a factor of 200, and you can see that my referencing -40dB of attenuation was an underestimate. I do wonder what details it was that you thought you might recall.

Quite disappointed by HN standards of self-moderation yet again.

Re: Test Microwave for Radiation Leakage

#90

Post by kurthr »

femto wrote: post #66

Neat idea, though it's not a definitive test. In my experience a microwave oven cavity provides about 40dB attenuation, and it's possible to maintain an LTE connection with that sort of path loss. Hint: If you're ever doing radio work in the field and need an instant Faraday cage a microwave oven is a good candidate. Turn the power off first to reduce the risk of accidentally irradiating your device, but leave it plu…

I'll confirm this works very well for 3G (600-900MHz) although I cut the hot off the plug out of paranoia when using one this way. Some of the 4&5G bands are up above 3GHz where it won't work so well.

Since your WiFi signal, however is almost exactly the same and there are many apps that will show and record signal in dB (as described in TFA). You could measure while the door open/closed if you're really careful not to turn it on. The lithium battery fire could respond very badly to water!

Post reply on HN