Microwave oven screwing up my wifi?

[e9999]

ummm....

got a new microwave oven (big Panasonic from Costco, model 797 something).

Well, tried it out and it messed up seriously my wifi (2.4GHz g ) system. Access to Internet virtually stopped when the oven was going even at 1/2 power.

Never noticed this before with my old (20yo) GE monstrosity. Maybe that one was operating at a different frequency. I think the new ones are something like 2.45 or so. Pretty close to the 2.4 wifi.


This common or a freak occurrence? Poor shielding?

Would it help to change channel on the wifi? Could move the router but that'd be difficult and not much distance to be gained.

 

[RobRed]

How close are your wifi devices to the Micro? I'd be a little scared right now

 

[e9999]

the router was about 15' from the oven (1250W rating) and the line of sight between router and computer about 10' or so.

I can see radio interference. I doubt it's dangerous to a human.

 

[Brentbba]

Sounds like you have a bad microwave my friend. No way there should be any interference. Have you tested to see if it messes with ham bands too? Just curious.

 

[e9999]

Sounds like you have a bad microwave my friend. No way there should be any interference. Have you tested to see if it messes with ham bands too? Just curious.

no, have not checked that. I might if I have a chance just for the heck of it.

What makes you think there should be zero interference? I doubt shielding on any of those is perfect and if you have 1000W at around 2.4GHz, any small loss would dwarf any wifi transmitters which I imagine are a fraction of a watt.

 

[KLF]

Do you have any cordless phones that you can see if there's interference?

I'd be putting that thing back in the box and taking it back. Try another brand.

 

[e9999]

Yup, I can return it but of course the same thing may happen with another one.
Yup, I have a 2.4G cordless phone but that's not causing any particular trouble that I can see so far but I'll check that too while I'm at it. My pingplotter software does normally show zero packet loss, though.


I did find something interesting. It turns out that I was running on Channel 11, which is about 2.46Gigs. Well, this particular microwave is running at 2.45 which is close. But if I would use channel 1, say, which is at 2.41 I might have less interference.

Of course,
1) I would have to change the dang channel which may be a pain
2) I had been using 11 cuz the standard (1?) was too noisy...

 

[rusty_tlc]

no, have not checked that. I might if I have a chance just for the heck of it.

What makes you think there should be zero interference? I doubt shielding on any of those is perfect and if you have 1000W at around 2.4GHz, any small loss would dwarf any wifi transmitters which I imagine are a fraction of a watt.

The chassis should be "sealed" well enough to prevent almost if not all Rf emissions. This is certified in a lab but not tested 100% in production.

 

[OregonLC]

FWIW e9999, mine does the same thing. It's a Kitchen Aid over the range high power thingy.

Regarding the RMF leakage... the spectrum used to heat food and the spectrum disrupting the wifi are two separate issues. One would be a hazard, the other a byproduct of the process. My brake booster pump screws with my CB on certain channels but that doesn't mean there's necessarily anything wrong. Same with the micro... could be a number of things bleeding into the 2.4 range not just the emitter.

 

[e9999]

this is not an isolated incident. I read plenty about it online. Seems fairly common in fact. But most folks may not notice it because one does not use microwave very long typically and a slowdown may not be readily noticeable for many wifi computer uses like browsing the internet for instance. Or one could instead blame the ISP or the "network". I suspect it may be noticeable if you are watching a movie without buffering though, but I don't know how often that happens.

I doubt oven shielding is perfect. For one thing, the door window has got to let some stuff through since it's mostly transparent. As I was saying, if you have a 1250W oven, one would not be surprised to see, say, a few watts of "lost" energy which might then dwarf the power of a typical wifi router. (I've seen 100mW quoted as typical for a router.)

 

[OregonLC]

I doubt oven shielding is perfect. For one thing, the door window has got to let some stuff through since it's mostly transparent.

Funny story: buddy goes to visit mom cross country. Hadn't seen her for a while. She had heath issues including an implanted pacemaker/defibrillator. Doc told her not to be within 12 ft of a microwave. So buddy shows up and finds the face of her microwave beat to heck. Turns out mom had spliced together several broom handles so that she could still operate her microwave remotely using the poke-it-with-a-long-stick method.

 

[rusty_tlc]

this is not an isolated incident. I read plenty about it online. Seems fairly common in fact. But most folks may not notice it because one does not use microwave very long typically and a slowdown may not be readily noticeable for many wifi computer uses like browsing the internet for instance. Or one could instead blame the ISP or the "network". I suspect it may be noticeable if you are watching a movie without buffering though, but I don't know how often that happens.

I doubt oven shielding is perfect. For one thing, the door window has got to let some stuff through since it's mostly transparent. As I was saying, if you have a 1250W oven, one would not be surprised to see, say, a few watts of "lost" energy which might then dwarf the power of a typical wifi router. (I've seen 100mW quoted as typical for a router.)

Just because something is transparent to visible light does not mean it is transparent to Rf. Room size Faraday cages for sensitive Rf testing are commonly made out of copper screen to reduce cost.

Just a though but have you checked the ground on the outlet you are using? If the ground is open or faulty it could cause the Microwave to emit Rf.

 

[e9999]

Just because something is transparent to visible light does not mean it is transparent to Rf. Room size Faraday cages for sensitive Rf testing are commonly made out of copper screen to reduce cost.

Just a though but have you checked the ground on the outlet you are using? If the ground is open or faulty it could cause the Microwave to emit Rf.

well, if the glass were not transparent to RF to some extent, I imagine they would not put in the metal mesh over it. but customers want a window so they have to have something to see through. (which is why I don't stand in front of the dang things when i can avoid it).

Yes, still need to check the ground, but I'm expecting that will be OK. I think this inteference is just the nature of most microwaves, I don't think it's defective by the usual standards. Will try changing channel first.

 

[e9999]

success! (partial)

I switched to Channel 1 and whereas before (on ch 11) everything just about stopped when the oven was on, now I can see that even though the throughput does decrease by about a factor of 5 (from say 15Mbps to about 3Mbps), that is still fast enough for a 1080p movie to keep up with the download. IOW I can still see a streaming movie in real time without much buffering need even if I turn the oven on. Now of course, if more than one computer were downloading big movies at the same time with the oven on that may no longer work but that won't happen often hopefully.

Interestingly, I could see some sophisticated download management when playing with different movies and different resolutions on Youtube and Firefox. Different rez would result in different download speeds for instance. For example, if I downloaded a movie at 360p the download speed might be very slow, like 0.5Mbps, whereas if I upped the rez to 1080 with the same movie, it would suck data down at 15Mbps.


Anyway, bottom line is that by switching to channel 1 from 11 I now have a reasonable G wifi throughput again even with the oven on.

 

[rusty_tlc]

well, if the glass were not transparent to RF to some extent, I imagine they would not put in the metal mesh over it. but customers want a window so they have to have something to see through. (which is why I don't stand in front of the dang things when i can avoid it).

Yes, still need to check the ground, but I'm expecting that will be OK. I think this inteference is just the nature of most microwaves, I don't think it's defective by the usual standards. Will try changing channel first.

The screen is part of the Rf shielding. It allows visible light to pass through but stops the longer Rf wavelengths. That is what I intended when I said "transparent" to visible light.

I would never assume a ground was okay, even in our brand new home there were a couple of outlets that had open grounds. In the older home we lived in before the PO had done all of his own electrical "repairs" and almost none of the outlets had a good ground.

 

[Bull Moose]

Funny story: buddy goes to visit mom cross country. Hadn't seen her for a while. She had heath issues including an implanted pacemaker/defibrillator. Doc told her not to be within 12 ft of a microwave. So buddy shows up and finds the face of her microwave beat to heck. Turns out mom had spliced together several broom handles so that she could still operate her microwave remotely using the poke-it-with-a-long-stick method.

Priceless.

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