I remembered that a microwave oven works on 2.4 GHz which is same as wifi frequency so I did a test for the leakage for my microwave oven, I put the oven's door in front of 2.4 GHz wifi router(line of sight) with a distance of 1.5 meters I used wifi analyzer(android app), it gives -40 dBm when the door open and -60 to -65 when it's closed. I repeated the experiment many times and get the same result, the signal decreased by 20 to 25 dBm, which mean if oven work on 1000 watt it will be like a wifi antenna of 10 watts. so is my oven have acceptable leakage?

  • \$\begingroup\$ Just to make sure I understand your setup: You put your phone in the microwave and tested the signal strength of the router once with the door open and once with the door closed. The difference is your attenuation of the microwave casing? \$\endgroup\$ – jusaca Jul 20 '19 at 13:28
  • \$\begingroup\$ yes, you understood my setup. \$\endgroup\$ – Computer_guy11 Jul 20 '19 at 13:31
  • \$\begingroup\$ Do you have reasons to believe that the oven is leaking to much microwave radiation? If so, I would not connect it so the grid anymore, 10W is waaay to much leakage (also magnetrons only have like 65% efficiency, so you would only habe 6.5W leakage. Still way to much! But I could also imagine, that the measurement with the phone is very inaccuarate. This much leakage does not seem realistic to me, if the oven is in good condition. \$\endgroup\$ – jusaca Jul 20 '19 at 13:51
  • \$\begingroup\$ yeah, router power level measurements do a lot of things, but actually power measurements is not among them. \$\endgroup\$ – Marcus Müller Jul 20 '19 at 13:59
  • \$\begingroup\$ Wave a working phone around the OUTSIDE of a working oven. Even a well sealed oven may have some detectable leakage around the door edges. Microwave ovens in a direct path from WiFi router to destination often cause interference. \$\endgroup\$ – Russell McMahon Jul 20 '19 at 13:59

Routers typically simplify (to the point of lying) in their power level displays:

Your router doesn't really care about the power level of your reception; what matters to it is that it's not far too weak or far too strong (but as you know from operating devices from orders of magnitudes of different distances from the router, that's not often a problem), and how the power relationship of desired signal to (noise plus interference) is.

So, they display some number that is often something like "if there was true gaussian, stationary, white noise, at powers like we'd get for a fixed noise figure, we'd have this much signal energy." Note that this is implemented differently by different WiFi chipset vendors, is partially specified, is mangled by driver and UI software.

Problem is that the things that are hard on the reception quality are exactly these interferences that are correlated to the signal, that are bursty and high-powered, that take the same statistical properties as subcarriers. So, not really closely linked to received signal power.

So, your router's power display tries to be helpful at displaying how good reception is. It really doesn't try to be an RF power analyzer.

That means I wouldn't quite lose my head over your microwave oven's leakage just based on your router's quality assessment.

If you really had 10W (more like at most 6W, considering efficiencies and internal absorption) escaping your microwave oven, you could even just get e.g. fridge-cold margarine and smear all gaps around the door and check whether that margarine gets liquid. (Be careful – don't smear the vents of the thing; the warm air that comes from cooling the power components inside needs to go somewhere, and that would a) raise a false alarm and b) smell bad from the inside after a couple of weeks).

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    \$\begingroup\$ I knew that router transmit RF power regardless of the receiving devices, I used the phone inside the oven to read the signal power of the router in both cases(close and open door), even if the app(wifi analyzer) not only measure the power of the wifi signal, but its gives an indication of how signal attenuated when the door is closed by comparing the dBm in both situations (closed and opened door) which is -20 dBm \$\endgroup\$ – Computer_guy11 Jul 20 '19 at 16:43
  • \$\begingroup\$ seriously, none of this has any meaning. This is all based on the same flawed data. \$\endgroup\$ – Marcus Müller Jul 20 '19 at 16:47
  • \$\begingroup\$ i really don't understand your point, i know that dBm=10*log10(p/0.001) in the app maybe it uses statistical(average) to show the result but it also gives an indication how the signal is a strength(power) could you clarify your point more \$\endgroup\$ – Computer_guy11 Jul 20 '19 at 16:57
  • \$\begingroup\$ I just found this maximeayotte.wixsite.com/mypage/single-post/2019/01/10/… he used the same procedure I did \$\endgroup\$ – Computer_guy11 Jul 20 '19 at 17:05
  • \$\begingroup\$ @Computer_guy11 cool, you found a random sound engineer on the internet, that disagrees with multiple electrical engineer domain experts :) Now, any smarter? \$\endgroup\$ – Marcus Müller Jul 20 '19 at 17:40

Just to calm you down on the leakage issue, I believe uwave magnetrons output is aimed at the opposite wall, and is highly directional.

Just saying.

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