Microwave ovens that don't use the 2.4GHz frequency?
March 21, 2015 1:49 PM Subscribe
I need a microwave oven that won't kill my Sonos wifi signal when I'm trying to prepare dinner and also listen to music...
Installing a new Sonos system and am finally trying to overcome wifi interference in my kitchen from the microwave. I have looked every way possible at running my system on the 5GHz router frequency, but after considering how many iPhones will be controlling the Sonos, the limited/lower range of the signal at 5GHz, etc, I'm wondering if instead it would be possible to just get a microwave that doesn't do this. There was some suggestion in the Sonos forums that certain brands are better or worse than others with this issue. All online research seems to be directed at putting the music network on a 5GHz band, so perhaps I'm missing something. I need to keep mu iPhone on the 2.4GHz network for improved range. Calls to local appliance dealers have been [not surprisingly] fruitless.
Installing a new Sonos system and am finally trying to overcome wifi interference in my kitchen from the microwave. I have looked every way possible at running my system on the 5GHz router frequency, but after considering how many iPhones will be controlling the Sonos, the limited/lower range of the signal at 5GHz, etc, I'm wondering if instead it would be possible to just get a microwave that doesn't do this. There was some suggestion in the Sonos forums that certain brands are better or worse than others with this issue. All online research seems to be directed at putting the music network on a 5GHz band, so perhaps I'm missing something. I need to keep mu iPhone on the 2.4GHz network for improved range. Calls to local appliance dealers have been [not surprisingly] fruitless.
The 2.4GHz band of spectrum where WiFi and microwaves work don't require a license, and so lots of devices use it. It also is a pretty good frequency for cooking as it has both good energy transfer and good penetration in most foods.
Better makes of microwaves have better and more effective shielding and I think you should look to that as a way to prevent interference. Also, because microwave ovens radiate at 2.450 GHz this has greater potential to overlap at the higher WiFi channels (wifi being from ~2.41 to ~2.48GHz) - point is, try using channel 1 and see if that helps. I'm not real optimistic, but it's free and might work in your situation.
Otherwise, you can get WiFi access points that feature higher output power and interference handling. But really, you're best off putting everything at 5GHz.
posted by Pogo_Fuzzybutt at 2:23 PM on March 21, 2015
Better makes of microwaves have better and more effective shielding and I think you should look to that as a way to prevent interference. Also, because microwave ovens radiate at 2.450 GHz this has greater potential to overlap at the higher WiFi channels (wifi being from ~2.41 to ~2.48GHz) - point is, try using channel 1 and see if that helps. I'm not real optimistic, but it's free and might work in your situation.
Otherwise, you can get WiFi access points that feature higher output power and interference handling. But really, you're best off putting everything at 5GHz.
posted by Pogo_Fuzzybutt at 2:23 PM on March 21, 2015
Manufacturers are required to build RF-emitting industrial, scientific and medical devices within specific frequencies, the ISM bands. The microwave frequencies used for both ISM devices and unlicensed low-power radio devices (Wi-Fi, cordless phones, etc.) in the US are 915Mhz, 2.4Ghz, 5.8Ghz, and some even higher frequencies.
There are industrial microwaves that run at 915MHz instead of 2.4GHz, and they do work well for cooking, but generally work best with a large cavity and also cannot be sold in regions where interference on the 915MHz radio band is not allowed - whereas 2.4GHz is good worldwide. A 5.8GHz (or higher) microwave, on the other hand, would technically work, but would require more power to effectively heat food and as such be an unpopular product, as 2.4GHz microwaves already use very substantial amounts of power while they operate.
As such, for a home microwave, it's pretty much going to be 2.4GHz, take it or leave it.
The problem is, Sonos only works with 2.4GHz for completely wireless networks. That's true both for devices that are connected directly to your wireless network, and those connected to a Sonos bridge. A handful of Sonos products do have 5GHz support built in, but only for surround-sound applications. So, you're pretty much stuck with any microwave you buy and your Sonos system at 2.4GHz.
Now, it is possible that your microwave, if it was damaged or is very old or perhaps particularly cheap, is not shielding the 2.4GHz signal from leakage as well as it should. We always experienced interference with our 90s-era microwave, but never with our current late-aughts microwave. It may be worthwhile to either borrow a microwave or purchase one at a store with a liberal return policy and see if the issue is actually with your old microwave leaking more than it should.
Otherwise, if decent modern microwaves are still causing interference, the only way you'll be able to get around it is by using the wired Ethernet port on the Sonos speakers closest to the microwave (assuming that an Ethernet port is available on that model of speaker). You may be able to use Powerline Networking to extend a wired connection from your router into the area where the affected speakers are. You could also purchase a dual-band router that operates on both 2.4GHz and 5GHz, and then get a 5GHz media adapter to extend wired Ethernet to that location wirelessly, outside the 2.4GHz band.
posted by eschatfische at 2:32 PM on March 21, 2015
There are industrial microwaves that run at 915MHz instead of 2.4GHz, and they do work well for cooking, but generally work best with a large cavity and also cannot be sold in regions where interference on the 915MHz radio band is not allowed - whereas 2.4GHz is good worldwide. A 5.8GHz (or higher) microwave, on the other hand, would technically work, but would require more power to effectively heat food and as such be an unpopular product, as 2.4GHz microwaves already use very substantial amounts of power while they operate.
As such, for a home microwave, it's pretty much going to be 2.4GHz, take it or leave it.
The problem is, Sonos only works with 2.4GHz for completely wireless networks. That's true both for devices that are connected directly to your wireless network, and those connected to a Sonos bridge. A handful of Sonos products do have 5GHz support built in, but only for surround-sound applications. So, you're pretty much stuck with any microwave you buy and your Sonos system at 2.4GHz.
Now, it is possible that your microwave, if it was damaged or is very old or perhaps particularly cheap, is not shielding the 2.4GHz signal from leakage as well as it should. We always experienced interference with our 90s-era microwave, but never with our current late-aughts microwave. It may be worthwhile to either borrow a microwave or purchase one at a store with a liberal return policy and see if the issue is actually with your old microwave leaking more than it should.
Otherwise, if decent modern microwaves are still causing interference, the only way you'll be able to get around it is by using the wired Ethernet port on the Sonos speakers closest to the microwave (assuming that an Ethernet port is available on that model of speaker). You may be able to use Powerline Networking to extend a wired connection from your router into the area where the affected speakers are. You could also purchase a dual-band router that operates on both 2.4GHz and 5GHz, and then get a 5GHz media adapter to extend wired Ethernet to that location wirelessly, outside the 2.4GHz band.
posted by eschatfische at 2:32 PM on March 21, 2015
Newer panasonic inverter microwaves don't do this(and probably other brands inverter drive models). I got one for super cheap thrifting and was excited to discover this. My semi-educated theory is that it has something to do with the digital power supply not putting out as much RFI/EMI noise garbage. They also are rated at less power from the wall and seem more efficient. I've noticed it takes a lot less inrush current to start the magnetron than previous microwaves i've owned...
It also cooks my food obscenely fast. Like, stuff is searingly hot after 30 seconds.
I can stand right in front of it using my phone on wifi, which should completely murder the signal. No change. Even on crappy devices.
A+
Oh, and on the 915mhz thing... My coworker scored a dual-magnetron high powered commercial microwave recently that operates on those bands. It causes no interference either, and was cheap used, but required a special high amperage power socket to be installed in his kitchen(which he did, he's an electrical engineer type). Personally, i'm happy with my non-interference-generating cheapo panasonic. Only complaint is the door sticks.
posted by emptythought at 3:12 PM on March 21, 2015
It also cooks my food obscenely fast. Like, stuff is searingly hot after 30 seconds.
I can stand right in front of it using my phone on wifi, which should completely murder the signal. No change. Even on crappy devices.
A+
Oh, and on the 915mhz thing... My coworker scored a dual-magnetron high powered commercial microwave recently that operates on those bands. It causes no interference either, and was cheap used, but required a special high amperage power socket to be installed in his kitchen(which he did, he's an electrical engineer type). Personally, i'm happy with my non-interference-generating cheapo panasonic. Only complaint is the door sticks.
posted by emptythought at 3:12 PM on March 21, 2015
While I was trying to avoid mentioning brands in my post above, I should probably mention that the new microwave I got that hasn't given me any 2.4GHz interference problems is also a Panasonic w/inverter technology.
posted by eschatfische at 3:21 PM on March 21, 2015 [1 favorite]
posted by eschatfische at 3:21 PM on March 21, 2015 [1 favorite]
One option is to shield your microwave. Foil-lined cardboard sheets would work-- you'll have to respect the need for the microwave to emit hot air, but hot air is generally okay with going around corners or venting through layers of your shield, while microwaves won't easily go around corners by comparison.
I'm assuming your microwave is not built in, as that would probably have killed off your notion of changing microwaves. Get a sheet of foil under the microwave, covering the sides, top (if unvented), and loosely at the back (where the vents probably are) to allow airflow but block at least the line-of-sight radio waves coming out. The front is probably well shielded already, for safety reasons, but you could have a removable shield that you stow on top of the microwave when you're using the door and keypad. I'm not sure how much radio interference would come from the power cord, but it's possible foil-wrapping that would also help.
posted by Sunburnt at 4:44 PM on March 21, 2015
I'm assuming your microwave is not built in, as that would probably have killed off your notion of changing microwaves. Get a sheet of foil under the microwave, covering the sides, top (if unvented), and loosely at the back (where the vents probably are) to allow airflow but block at least the line-of-sight radio waves coming out. The front is probably well shielded already, for safety reasons, but you could have a removable shield that you stow on top of the microwave when you're using the door and keypad. I'm not sure how much radio interference would come from the power cord, but it's possible foil-wrapping that would also help.
posted by Sunburnt at 4:44 PM on March 21, 2015
Response by poster: Thank-you for all the incredibly helpful and educational answers. Really appreciate the assistance. I'll keep looking at using the 5G band but suspect a new microwave or better shielding would go a long way.
posted by docpops at 3:09 PM on March 22, 2015
posted by docpops at 3:09 PM on March 22, 2015
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