USB HUB – Interference

Laptops these days don’t usually have as many USB ports as they once use to. So I’m always trying to be more efficient in the wireless work that I do. What better way to do my job faster than with a USB HUB. Now I can have all my goodies and toys plugged in. There’s nothing holding me back now!!!…..

20150901_152130

This is the point where my smile turns into a sad clown face.

Although I was beaming at my new setup, I just had this funny feeling that it might be too good to be true. I got everything setup and started to test out the new rig at my home.

Everything looked good so far within Ekahau Site Survey (ESS).

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I was enjoying what I was seeing so far, and pumping myself up for my next survey work. Then I noticed something unusual.

ohno

I set all three USB Proxim cards to only scan channels 1-11. If you zoom in, you’ll notice that the top two USB adapters are only seeing two Access Points…total. More importantly, the signal and noise are almost identical. Say what! The noise is being heard at -60dBm??? Is my roommate heating 10 hot pockets at once? Arrgggh…

Back it up, back it up.

BEEP BEEP BEEP

So not only are all three adapters not hearing all of the nearby Access Points the same, but my noise floor is essentially being destroyed.

Confused I am. Solve puzzle I must.

Pop open my trusty Chanalyzer and behold. Houston we have a problem.

usb hub test

I ran some tests with the USB HUB turned on and off, and holy guacamole Batman. What a piece of junk (this is the USB HUB I purchased). You can clearly see the affect it has on any captures I might be doing on L1 or L2. It essentially makes all data gathered as useless as an ejection seat on a helicopter.

The USB HUB is a USB 3.0 device, and I opted for the 3.0 vs 2.0 because I was a bit concerned at how much throughput I’m going to be able to send across a single USB 2.0 port, with 3+ devices on the HUB.

I’m still concerned about it. I don’t like not knowing if I’m missing packets/frames/delicious RF etc. So now knowing that I can’t trust my USB 3.0 HUB, or any for that matter, I’ve decided to forgo any future USB HUBS for interference and potential bottle neck reasons.

I investigated the matter a little more to try and figure out why I was getting so much interference, and as it turns out, USB 3.0 does indeed generate interference in the 2.4 GHz frequency range. How super inconvenient. Click HERE to read more from Intel.

So for now, I’ll stick with my super awesome and ultra handy 4 inch USB dongles.

dongles

I hope you enjoyed this post.

-Nolan

5 thoughts on “USB HUB – Interference

    • Nope. I just avoid hubs all together now because they are a bit of a pain to deal with and I only use two USB adapters at the same time. The rear backside of my laptop has two USB ports so it works perfectly.

      Like

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