ZoneMinder Forums

Hi,

is anyone using the 2.4Ghz wireless cameras from x10.com (or anywhere)? I've got 3 wired b/w cameras that work fine, but have one wireless color camera that is combined with a motion-sensor light.

This camera seems to have a lot of sync problems related to (I suspect) my 2.4 Ghz phones. I'm wondering if anyone has any filtering ideas for getting rid of this kind of "rolling" interference?

By the way, ZoneMinder is pretty cool stuff!

Kevin

Hi,

Did you try unplugging your phones to see if the sync problems go away?

Roger

No, but I did see it get considerably worse when the phones were in use and a coworker of mine with the same cameras has confirmed that his problem definitely goes away when his phones are powered off.

I guess you are just trying to confirm that the problem is my phones, but I'm not getting rid of them - they are only a couple months old!

Kevin

Yes, I was just thinking that since it would be easy to check, there wasn't any need to run on the suspicion alone.

Does your camera or your phones have any settings to tweak the frequency?

Roger

Yeah, I would do it, too but then I would have to re-program the date/time settings on my phone... I may do it when I have a few minutes.

I tried the different channel settings on the camera without any positive change. I'll ahve to dig out the phone docs and see what I can do there. I do remember X10 having a blurb about the 4 frequencies they use, so I'll do more research there...

Kevin

2.4GHz stuff seems to be prone to all sorts of interference. I've got one 2.4GHz video link for a camera to which I'm not able to run cable at present, and it captures all sorts of strange events that are caused by interference. Just waling around somewhere between the camera and the receiver seems to be enough...

Might I suggest one of those homemade directional antenna configurations. Some are made with potato chip cans IIRC. Since your camera is not moving, putting a directional antenna on it should block out a large precentage of your noise unless your AP is what is the problem. If the AP is the problem then maybe building a multi-node directional antenna for a camera-only AP would work?

This should be cheap and easy to do since there are instructions on this kind of stuff all over the web. A Google seach for "pringles wifi antenna" shows:
http://www.turnpoint.net/wireless/has.html
http://airshare.org/learn/articles/feat ... ingles.cfm
http://www.cantenna.com/howtouseit.html ( have a $19.95 kit )

and many more.

The cameras I am talking about are 2.4Ghz spread-spectrum wireless, not 802.11 ethernet (aka WiFi), so that is not a choice here.

Kevin

unix-guy wrote:The cameras I am talking about are 2.4Ghz spread-spectrum wireless, not 802.11 ethernet (aka WiFi), so that is not a choice here.

Kevin

I'll check but I could swear that both WiFi and Bluetooth are 2.4GHz spread-spectrum formats. If so, the same antenna designs should work but that bit about the AP would not because your reciever is something other than an AP. But putting one of those directional antenna's on each end would reduce your interference since it limits the signal "view".

I'll go do some searching on this but I'm pretty sure your stuff is in the same spectrum and tech as WiFi and Bluetooth.

UPDATE: It looks like they are both 2.5 GHz spread-spectrum but slightly different. different enough for those directional antenna to not work? I wouldn't think so. Here's some text from a post found by googling "2.4Ghz spread-spectrum 802.11":

Most 2.4GHz phones use frequency hopping spread spectrum (FHSS) technology that operates within the 2.4GHz spectrum. FHSS hops from frequency-to-frequency across the entire 2.4GHz spectrum. 802.11b WLANs, on the other hand, use direct sequence spread spectrum (DSSS), which transmits within approximately one third of the 2.4 GHz spectrum. Because FHSS jumps across the entire spectrum while DSSS stays in only one portion, a FHSS 2.4GHz will clobber an 802.11b network, causing interference or even failure.

Well, there is no external antenna or connector, so it still won't work

I also have WiFi in my house, in fact my ZM box is running wireless with NDISwrapper... I haven't seen any issues with phone/WiFi interfering with each other...

Kevin

unix-guy wrote:Well, there is no external antenna or connector, so it still won't work

I also have WiFi in my house, in fact my ZM box is running wireless with NDISwrapper... I haven't seen any issues with phone/WiFi interfering with each other...

Kevin

no antenna? oh well, all I can say is I tried. Most likely, any "real" solution is going to require hardware hacking of the device and a heck of alot more work then building a tin can directional antenna. As a matter of fact, if you search google with the string I mentioned, you'll find some links which basically say that to correct the interference, your best bet is to get another phone that uses either 900MHz or 5GHz. Maybe replace the camer with a WiFi camera...

Regarding you not seeing problems with your WiFi setup goes, it's most likely due to the error correction built into the TCP protocols. You are likely dropping packets and just down't know it.

That's all I have.

You should be able to wire up a directional antenna just like a wifi device. You may have to take apart the camera and receiver to remove the old antenna and attach the new one. I'm sure that would void warranties. If they have little stubby antennas like my GE camera set, you could try and build a parabola around them using aluminum to block interference. Ground the aluminum so you dont get reflections. It helped with mine a little. I get a knocking sound still whick I think is the wifi card in my router. I will test that next time I have to power it down.