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Interference from 900 MHz baby monitors?


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Has anyone experienced problems with their Zigbee network related to use of a 900 MHz baby monitor? I'd heard that 2.4 GHz phones are a problem, and as a result we retired a phone that I really liked, but in the last few days we've had 4 zigbee crashes and the only new thing I've introduced is a new 900 MHz 2-way baby monitor. Is that band also known to cause interference?

We've been using another 900 MHz monitor for months now with no problems. I've since disconnected the new one and had no problems for 24 hours. I'll do that for another couple of days, and if no more problems I'll plug the new one back in and see if the problems return.

Can anyone advise me on what are the problematic ranges? According to Wikipedia:

This standard specifies operation in the unlicensed 2.4 GHz, 915 MHz and 868 MHz ISM bands. In the 2.4 GHz band there are 16 ZigBee channels, with each channel requiring 5 MHz of bandwidth. The center frequency for each channel can be calculated as, FC = (2405 + 5*(k-11)) MHz, where k = 11, 12, ..., 26.

My HC300 is serving Zigbee on Channel 14. Is it likely that picking a different channel there would help?

Thanks!

--Jason

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Unless your 900 MHz monitors are really 2.4GHz monitors, or they are just putting out a lot of broadband interference, they shouldn't affect Zigbee at all.

Zigbee is definitely 2.4GHz, and channel 14 should be outside the Wi-Fi part of the 2.4 GHz spectrum.

RyanE

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Unless your 900 MHz monitors are really 2.4GHz monitors, or they are just putting out a lot of broadband interference, they shouldn't affect Zigbee at all.

Zigbee is definitely 2.4GHz, and channel 14 should be outside the Wi-Fi part of the 2.4 GHz spectrum.

RyanE

The packages and documentation are all decidedly 900 MHz. Is there any way for a lay person to determine what frequencies a device is giving off? We're now about three days into having it turned off and have had no more Zigbee problems. I'm going to plug it back in tonight and see if Zigbee starts crashing again.

Can anyone give me a sense of what the 16 channels mean? Do they correspond to narrow bands clustered around 2.4 GHz? How much of a difference is changing that channel likely to have, and are there certain channels which just tend to work better with C4 equipment than others?

Thanks!

--Jason

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14 is the default because it lays outside of the spectrum used by Wi-Fi.

Zigbee is 16 channels, that don't overlap. Wi-Fi channels are much wider, and there are only 3 non-overlapping channels on Wi-Fi.

Channel 1, 6, and 11 on Wi-Fi don't overlap, any other choice overlaps with other Wi-Fi Channels.

RyanE

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So, as of last night, with the monitor disconnected for 3 days we'd had no problem. I plugged in the monitor when we went to bed and in the morning nothing Zigbee worked. I turned off the monitor, restarted the system twice and now it all seems to be running smoothly for the last several hours.

The manufacturer tells me that it's definitely 900 MHz. This is the model:

http://www.amazon.com/Evenflo-Whisper-Connect-Nursery-Monitor/dp/B000CDNECQ

If we have to we'll go find another monitor, but this one was the most highly related. Anyone have any ideas on other diagnostic options before I give up? Is it worth trying different Zigbee channels? If so, how does one go about that?

Thanks for any help!

--Jason

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My bluetooth head set for my cell gets all kinds of funk when im in the house around the zigbee. As i get closer to divices the funk gets louder. Our 2.4 baby baby monitor used to get interference when i used the c4 remote, but now with the v2 for some reason does not.

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Yeah, I suspect this sort of thing is going to get more and more common as more of our household "stuff" gets unwired. When we built our house last year I put in about 80 Cat6 drops covering almost every room in the house (there's one in the laundry room and 2 in the attic!). A few people thought I was crazy ("Haven't you heard of wireless?") We have wireless, and it's great when you need to roam, but if I'm at my desk I'd just as soon not risk locing my VPN connection because my baby monitor is having a fight with the alarm system. I like wires . . .

--Jason

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Yeah, I suspect this sort of thing is going to get more and more common as more of our household "stuff" gets unwired. When we built our house last year I put in about 80 Cat6 drops covering almost every room in the house (there's one in the laundry room and 2 in the attic!). A few people thought I was crazy ("Haven't you heard of wireless?") We have wireless, and it's great when you need to roam, but if I'm at my desk I'd just as soon not risk locing my VPN connection because my baby monitor is having a fight with the alarm system. I like wires . . .

--Jason

wires are good indeed. The zigbee stuff is exactly what i think wireless is really practical for. wifi is nice when you need to check the weather or get directions, but sending credit card info out into the air even with wpa makes me sorta nervous.

And fiber is almost cheaper than cat6 now... common having a 10Gb backbone is just so geeky kewl. Even if you can only use 12% of it. :o) plus it justifies buying a nice chatsworth or mid atlantic rack for your fiber switch, and the rest of the AV gear.

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What?!?!?! Fiber almost cheaper than CAT6?!??! Are you nuts!??!?

Fiber is approx $1 per foot

CAT6 is approx $.20 per foot

To terminate Fiber is approx $100 per end

To terminate CAT6 is approx $15 per end

To certify Fiber is approx $125 per run

To certify CAT6 is approx $75 per run

10/100/1000/10000 Switch for Fiber is approx $250 per port

10/100/1000/10000 Switch for CAT6 is approx $100 per port

So how is it even CLOSE to being about the same?!?! Don't mean to poke at ya punkrock - but you're numbers are a little off there... :)

But - the original conversation... IMPO - wires will NEVER go away... there is just too much interference in the wireless spectrum... and I don't see that being fixed in our lifetime. I've got an HC-300 that sits 15ft away in a room that it controls. This one room has problems with wireless signals and even Zigbee... so we put that HC-300 on to channel 15 - separate from the rest of the Zigbee network... and the remots that are only 15ft away (no walls or anything) STILL have problems talking sometimes... there are times it requires TWO button presses to get a signal through. Not that I want to wire in my remote directly - but I certainly wished there was an option to hardware the light switches in the room... :(

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ok then.. plenum cat6... :)

and ends on fiber are not nearly that expensive. I assume you are talkking labor time to do them.

we just purchased 1200 feet single mode fiber incluiding interduct for 800 bucks...

cat6 ends 15$????

you need to stop buying you networking gear at nordstrom.

;)

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