WiFi NIC and 2.4GHz video sender!!

[ChrisW]

Hi all,

I hope this is not covering old ground so to speak but I have a problem with interference on my ISM band video sender. Basically I've proven that this is caused by my pc just a few feet away. This wasn't really a supprise seeing that they opperate on the same band however I set my AP to use a much higher channel (ch11) and this cured the interference a lot. My video sender uses ch1. However... and this is the big question... I now get occasional interference on screen (every 10 seconds or so).

Anyway after looking around on the net I descover that wireless NICs transmit a "probe request" every so often on all channels to obtain info from any APs that are in the coverage area. My guess is that's what's causing this sporradic wideband noise.

So my question is does this sound like the true cause of the problem?? And if so what can I do to disable NIC probe requests???

Thanks in advance!

Chris.

[golfnut]

If you're using 802.11g, try switching 802.11b which has less side band noise.

Other than that, I'm not sure...

Greg

[ChrisW]

Hi,

I did switch to 11b but this didn't stop the interference. The noise I'm seeing on screen doesn't seem to actually be "main channel data noise". If I set my AP to use the same channel group as the video sender (1-4) I get a continuous stream of noise displayed on screen. This is obviously expected but as I say, moving the AP channel to 5 and above cures this and just leaves an intermittant burst of noise every so often. From what I can gather the only time a wireless NIC transmitts outside it's main data channel is when it's probing for other APs.

I'm considering resorting back to good old cat5 in this case!! :(

[ConnClark]

ChrisW,

It sounds like you probably know what the problem is (the channel probe request) . Dealing with it however may not be possible unless the driver allows you to turn this off. Your options are find a driver that does, or write your own. Sounds like you will be going back to cat5.

good luck,

Conn Clark

[ChrisW]

... Good old CAT5 installed and all is working fine!

Just goes to show how a wireless video sender can be made useless due to a wireless lan operating nearby. If windows and or the NIC drivers supported "passive scanning" rather than "active scanning" this problem wouldn't be an issue. I know active scanning in NICs has it's advantages but I guess this is one big dissadvantage that is not widely known. I guess your ok if you only have 802.11x products in your house but products that require a clear interference free ISM channel and have no kind of data error detection are bound to be effected by active scanning.

Anyway, off I go to sell the DWL-520+ on ebay!! :rolleyes:

Thanks to all who commented. :)