Scanning for WiFi interference
#1
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Scanning for WiFi interference
I have noticed that the baby monitor my parents gave us is affecting our home WiFi network. It was most apparent when I had the monitor sitting next to my laptop and found that my normal 18 Mbps was down to 5 or 6 Mbps. As soon as I moved the monitor away, my speed jumped back up to 12-13. When I turned the monitor off completely, it jumped back up to 18-19 Mbps.
A little research showed that the majority of baby monitors are running on the 2.4 Ghz spectrum. What I'd like to do is scan to see where the interference is worst so that I can adjust my router's wireless channel accordingly. However, every program and app that I can find only scans for other WiFi networks, not for non-WiFi interference.
Does anyone know of any programs or apps that do this? I'm not going to buy a $3000 Cisco RF spectrum analyzer just to solve this.
A little research showed that the majority of baby monitors are running on the 2.4 Ghz spectrum. What I'd like to do is scan to see where the interference is worst so that I can adjust my router's wireless channel accordingly. However, every program and app that I can find only scans for other WiFi networks, not for non-WiFi interference.
Does anyone know of any programs or apps that do this? I'm not going to buy a $3000 Cisco RF spectrum analyzer just to solve this.
#2
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You could buy a Tektronix* RF spectrum analyzer instead. RSA306 USB Spectrum Analyzer | Tektronix
On topic: My router has a feature that scans channels for interference. But its also running aftermarket firmware.
*disclaimer, I work for Tek, buy our stuff
On topic: My router has a feature that scans channels for interference. But its also running aftermarket firmware.
*disclaimer, I work for Tek, buy our stuff
#4
If you want to know which channels are most heavily used by other wifi devices, there are smartphone apps to do that. Note that there are really only 3 non-overlapping channels for 802.11g -- 1, 6, and 11. The intermediate ones all overlap those three.
If you want to look for non-802.11 sources of interference like that baby monitor (or, worst of all, a microwave oven) then you need a device like the one Aidan linked. This is the realm of specialized test equipment, and it tends to be fairly expensive.
--Ian
If you want to look for non-802.11 sources of interference like that baby monitor (or, worst of all, a microwave oven) then you need a device like the one Aidan linked. This is the realm of specialized test equipment, and it tends to be fairly expensive.
--Ian
#5
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Or, as Aidenj said, log into your router and explore the more advanced options. My last router, which was made by Ξ i♣ea♫1g░P0ṅ (sorry, line noise) and running stock firmware, had this exact feature, where it acted as a primative spectrum analyzer and showed you the detected power on every channel.
#6
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Router is an Asus RT-N66U on stock Asus/Merlin firmware. There is an "auto" setting for channels but I don't think it shows you any details. Last I looked, leaving it on auto meant it was on channel 6 most of the time.
Is what I'm describing technically possible? It would seem like wifi devices would at least be able to detect RF signals within the wifi spectrums, but maybe not, if the radios are hard coded to only read wifi signals.
[edit: I guess that's exactly what you were saying, codrus.]
Is what I'm describing technically possible? It would seem like wifi devices would at least be able to detect RF signals within the wifi spectrums, but maybe not, if the radios are hard coded to only read wifi signals.
[edit: I guess that's exactly what you were saying, codrus.]
#7
You could also change the frequency the router operates on and see if it makes a difference, but that depends on the entire network & if all of your devices still connect.
I've used 'WiFi Analyzer' on iphone & android before. Works pretty well. If you walk around your home in a 4 corner point you could possibly interpret where outside signals are coming from if interference is also affecting by watching signals get stronger/weaker.
I've used 'WiFi Analyzer' on iphone & android before. Works pretty well. If you walk around your home in a 4 corner point you could possibly interpret where outside signals are coming from if interference is also affecting by watching signals get stronger/weaker.
#8
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Okay, making a little progress here. I found a thread from someone with the same baby monitor.
That's not good. That means channel A is just a bit below wifi 1, and channel B is just below channel 7. Channel C is above channel 11 but still within range.
I'm not sure if the post quoted means that the baby monitor is made with one of those three frequencies hard-coded, or if each monitor it can switch between the three. If I had to guess, I'd say they are probably hard-coded to just one of those frequencies.
Since it looks like the router has been on Channel 6, I guess I'll test Channels 1 and 11 and compare. Interference from other WiFi networks is basically nil so that doesn't matter.
I found on the Summer Infant website that their video monitors automatically use these three frequencies:
Channel A: 2.410 GHz
Channel B: 2.441 GHz
Channel C: 2.468 GHz
Channel A: 2.410 GHz
Channel B: 2.441 GHz
Channel C: 2.468 GHz
I'm not sure if the post quoted means that the baby monitor is made with one of those three frequencies hard-coded, or if each monitor it can switch between the three. If I had to guess, I'd say they are probably hard-coded to just one of those frequencies.
Since it looks like the router has been on Channel 6, I guess I'll test Channels 1 and 11 and compare. Interference from other WiFi networks is basically nil so that doesn't matter.
#13
It's unclear if an audio-only baby monitor would help in that sort of case, but "you will hear it cry" is not always true.
--Ian
#17
There is also a 5GHz unlicensed band (used for 802.11n), dunno if baby monitors use that frequency or not. With the higher frequency you lose a lot of drywall penetration, so it's trickier to use. I think there's a 900Mhz one as well (cordless phones used to use it), but I think it's pretty small and not all that useful for data or baby monitors.
--Ian
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Lulz at multiple negs for thinking it's not necessary.
EVERY parent is over protective at first. It's only natural to be that way. By the second kid, or a couple years in, you're much less so. Companies capitalize on that worry, selling padded this and that and all sorts of safety crap. BTW, don't get the cabinet locks. They are a pain, and the kid figures them out by age 2 anyway.
Kids are amazingly tough - if you let them, they can shake off what would leave an adult prone in bed for a day. As long as you don't shake the **** out of them, they can handle quite a bit.
EVERY parent is over protective at first. It's only natural to be that way. By the second kid, or a couple years in, you're much less so. Companies capitalize on that worry, selling padded this and that and all sorts of safety crap. BTW, don't get the cabinet locks. They are a pain, and the kid figures them out by age 2 anyway.
Kids are amazingly tough - if you let them, they can shake off what would leave an adult prone in bed for a day. As long as you don't shake the **** out of them, they can handle quite a bit.
#19
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Lulz at multiple negs for thinking it's not necessary.
EVERY parent is over protective at first. It's only natural to be that way. By the second kid, or a couple years in, you're much less so. Companies capitalize on that worry, selling padded this and that and all sorts of safety crap. BTW, don't get the cabinet locks. They are a pain, and the kid figures them out by age 2 anyway.
Kids are amazingly tough - if you let them, they can shake off what would leave an adult prone in bed for a day. As long as you don't shake the **** out of them, they can handle quite a bit.
EVERY parent is over protective at first. It's only natural to be that way. By the second kid, or a couple years in, you're much less so. Companies capitalize on that worry, selling padded this and that and all sorts of safety crap. BTW, don't get the cabinet locks. They are a pain, and the kid figures them out by age 2 anyway.
Kids are amazingly tough - if you let them, they can shake off what would leave an adult prone in bed for a day. As long as you don't shake the **** out of them, they can handle quite a bit.
If your kids have faced no serious health issues in their lives, I'm very happy for you. Not everyone has enjoyed the same experience.
#20
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There is also a 5GHz unlicensed band (used for 802.11n), dunno if baby monitors use that frequency or not. With the higher frequency you lose a lot of drywall penetration, so it's trickier to use. I think there's a 900Mhz one as well (cordless phones used to use it), but I think it's pretty small and not all that useful for data or baby monitors.
Yes, the 2.4 Ghz band is currently quite popular, for the very reason that it overlaps WiFi. This lets manufacturers use RF components which, because they are also used in WiFi devices, are extremely inexpensive, widely available, small, and efficient. While creating WiFi interference is not the primary intent, the choice of this band in newer devices based on its commonality with WiFi is a deliberate one.
The 900 Mhz band (actually 820-930, with some breaks in between) is also quite popular, though I'm not sure who is using it these days. This is where analog cell-phones and cordless home phones live, so there's actually a huge amount (relatively speaking) of available bandwidth here. While these devices are mostly obsolete, I'm pretty sure the band is still reserved for their use. Devices in this range will not interfere with WiFi.
Going back in time a bit, 27 Mhz and 46-49 Mhz are also popular bands, as this is where cheap remote-control toys and older analog cordless phones operated.
That having been said, Cuban women pronounce WiFi as "we fee." Don't believe me? Try it.