Microwave oven interferes with Alexa

[GB]

We have our Amazon Echo Dot next to our built in microwave oven. Starting the oven stops the Echo picking up a wifi signal. Is this a sign of excessive leakage, or is it simply par for the course?

[The Natural Philosopher]

yes, and yes

[Max Demian]

I find my microwave (and washer) sometimes interfere with FM radio, but not a Bluetooth speaker put on top. Come to think of it, it doesn't stop my smartphone from streaming podcasts over Wi-Fi if put near.

[Joey]

Correct.

No, doesn't happen with mine.

[williamwright]

Microwaves produce hundreds of watts of radio signal at 2.4GHz, which is one of the frequencies wi-fi uses. If only a tiny fraction of that signal escapes from the oven it's enough to interfere with a nearby wi-fi receiving device.

It's perfectly normal and you won't find an oven that doesn't do it.

Disregard answers here that are along the lines of 'mine does it' or mine doesn't do it', because they have no relevance to your situation. There are too many variables. The strength of the wi-fi signal the device is trying to receive can vary enormously because of distance and obstructions. The stronger it is the stronger interference would need to be to have an effect. The noise floor (interference from other wi-fi gear, typically) can be very significant and that will affect the level of interference from the oven that will have an effect.

You put any wi-fi receiver near a microwave oven and you are likely to get interference. It doesn't mean the oven is leaky.

Bill

[GB]

Thanks for the detailed explanation. It's not a problem that Alexa cuts out occasionally, but I was vaguely worried about radiation affecting people in the house.

Thinking about it a bit more logically and less hysterically, though,

2.4GHz is not ionising radiation. So, it presumably just warms you up slightly?

[Animal]

yes, which is not a problem.

[Joey]

No, which is why microwave ovens turn off the microwaves when you open the door and conventional ovens don't.

[Tim Streater]

Except too much of it might give you cataracts, long term, as the eye lens has no nerves to report pain. Thus you don't notice it.

Living in the US I had an eye-level microwave built-in over the stove - it was a standard type feature. Did that cause my much-later cataracts? Unclear.

[williamwright]

Put a glass of water near the oven. Run the oven for a good while. Observe if the temperature of the water rises. Then allow for the inverse square law, because you won't be so close to the oven.

Bill

[williamwright]

No, their experience is irrelevant for the reasons I explained, f****it.

Bill

[Brian]

Echo Dots, especially the Gen 2 ones, seem to have very poor Wi-Fi.

We have several and there are a couple of places which, while other things work fine on the Wi-Fi there, the dots tend to drop connection.

Neither place is more than 3 m from a router or Wi-Fi disk ( we have a mesh system in the house, the other place is in the motorhome. The router is perhaps 1.5 m from the dot. )

[John Walliker]

There are several reasons why microwave oven interference may affect Alexa in one household but not others:

1) Alexa is a dual-band WiFi device. If it connects to the WiFi base unit at 5GHz then it is unlikely to be affected. Many older base units are 2.4GHz only, in which case there is a much greater chance of interference. 2) If the base unit is a long way away, even with a dual-band unit there is a greater chance that it will pick the 2.4GHz band because this usually has better range. 3) If the 2.4GHz band is in use then if a channel has been picked which is near the middle of the band it is more likely to coincide with the oven frequency. So avoid channel 6 and try using channels 1 or 13. Avoid using 40Mhz wide channels on the 2.4GHz band, stick to 20MHz. Otherwise you will still overlap with the centre of the band. 4) Microwave ovens vary. The target frequency will be the centre of the band, but the tuning is affected by how much food is in the oven and where it is. As the turntable rotates the loading presented by an off-centre load varies and so does the magnetron frequency. Either channel 1 or 13 is more likely to miss this moving target but you will have to try it out to find which is better. The leakage power from a microwave oven is likely to be about the same as the transmitter power of a WiFi base unit. John

[Harry Bloomfield Esq]

It does to you, what it does to the food - it warms you up very, very slightly. Not enough leaks out to do you any damage, unless the case of the oven is in some way damaged.

[whisky-dave]

I thought it was down to the channel that your device is comunicating on, try to change the channel of the router and things you use, as this can also be done if you find intermittant problems which can be down to a Neighbours device on the same channel.

Maybe the only heating some will be able to affort this coming winter ;-)

[Paul]

My immediate concern would be with damage to eyesight.

"For lower intensities, lens changes may depend on the cumulative dose. At "nonthermal intensities", microwaves can act as a trigger and set off changes in the living tissues (e.g. Ca++ efflux). Some cataract-causing agents (alloxan and galactose) act synergistically with microwaves. Microwaves also accelerate formation of cataracts due to diabetes. The corneal endothelium can be damaged by microwaves alone or in combination with some drugs. Microwave degeneration of retinal nerve endings and a small increase in retinal permeability were also found in animals. The effect of long-term low-intensity microwave exposure on the human lens remains poorly understood."

Smartphones can cause glioma tumors on the side of the head where you've been sticking the phone. What frequency does a smartphone work at ?

I don't think leakage from a microwave oven is a joke. Fix it. Waiting until your eye is all f***ed up, that would be sad.

You can get various detectors, like ones that work thermally and use some kind of liquid crystal material. That would be the cheapest kind of detector you could get, as a strip of material.

There are also multimeter style devices. One even has a red LED on it which lights up when the exposure is "too much". These cost 1x to 2x what a Harbour Freight multimeter would cost. The claim here is "hundreds of dollars", well, it's just a PIN diode and an ordinary multimeter, so the component cost should not be expensive.

Walking away from the machine while it is running, is better than doing nothing. The penetration of 2.4GHz, reflections and so on, works just like your Wifi coverage, so the energy can travel some distance. But then the chemical effects probably fall off at a different rate, than "receiver sensitivity" would. Walking out of kitchen and down hallway, is likely good protection. If the microwave oven door is only held on by one hinge, walk out into the back yard :-)

One potential way for a microwave to leak, is if a DIY repair person cuts away the "dome" over the turntable motor, while doing a motor replacement. Think back to any mods you made.

The door has a "choke" on it. It's a feature on the door, where the door rests on the metal chassis.

The purpose of the choke, is to "short" the microwave signal. Apparently even if the door is a bit loose, the choke feature still works to some degree. The door leaks less, if the choke feature is present. It's a kind of tuned circuit, designed to work at the microwave oven frequency.

There's a lot of plastic in microwave ovens now, so it's hard to say how the choke cavity is implemented.

Paul

[williamwright]

I did, but some of my words had several syllables,so I would have lost you, f****it.

Bill

[Tim+]

I hope I never get so bored with life that I waste my remaining time arguing with known trolls…

Tim

[Animal]

That response is so retarded it simply has to be Rod

[Animal]

It's extremely effective & efficient. Safety is less certain.

PS some folks commenting on wifi might be unaware that nukes aren't 2.4GHz, they're around 2.4GHz (most anyway). The output frequency is unstable.