[Hackrf-dev] Finding the Interference with directional antenna?

Tamer Çelik tamercelik at gmail.com
Wed Dec 7 14:59:01 EST 2016


Hello again Scott,

After running some tests with HackRF, i can say that its not capable to
demodulate wifi signals due its sampling rate.
And yes, bandwidth is limited to 20MHz but issue occurs on all channels.
I am going to reanalyze everything with usb wifi dongle using inSSIDet as
mentioned by Garvin.
Do you recommend any other tool for such task?
I cant see which tool you sent on screenshot.
Thanks!



On Dec 7, 2016 18:03, "Scott Davis" <scottk5ta at gmail.com> wrote:

The HackRF is limited to a 20-MHz bandwidth, which is the approximate width
of a single wi-fi channel.  The wi-fi radio in your computer might be a
better sniffing tool, with some type of scanning/analysis software that can
show the entire band at once.  With the HackRF, you would need to ”tune
around” in frequency as well as spatial orientation to get an idea of the
signals in your vicinity.

-Scott

Example:

https://www.amazon.com/photos/share/hDY7ElO2wAnlVQQ0pesLH70qvAf4xv
iDvpI2SFtLfpv


On Dec 7, 2016, at 5:51 AM, Tamer Çelik <tamercelik at gmail.com> wrote:

Hello everyone,
Thanks for all the tips.
I was thinking getting this antenna: https://www.amazon.com/Super-
Power-Supply-Directional-Wireless/dp/B016APUGB6/ref=sr_1_8?s=pc&ie=UTF8&qid=
1481113798&sr=1-8&keywords=wifi+directional
It's compact and perfect for 2.4 GHz band. Just need to get an RP-SMA to
SMA converter adapter to use it with HackRF.

But i am still not sure where to look for interference.
Which software i should use and what should i look for?
I was thinking running SDRsharp with RX gain settings adjusted (low gain
settings to pick any signal from 2.4GHz device when i physically close to
it)
I have decided to use HackRF after i came across a wifi analyzer device
called Chanalyzer http://www.metageek.com/products/wi-spy/ They provide a
fancy software to determine possible intereference source and they are
quite expensive, around $2000.
But i think i won't need any fancy software or look out for any specific
waveform determine this interference, right?
Again, i have no idea what should i look for. (Noise? Waveform?)

Any ideas would be great.
Thanks!


On Wed, Dec 7, 2016 at 8:21 AM, Scott Davis <scottk5ta at gmail.com> wrote:

> There are many, many commercial directional antennas available for the 2.4
> GHz band.  Dish Network operates in the Ku-band, around 12 GHz, so their
> dishes are a bit small for 2.4, but it sounds like fun to play with
> one…it’s a lot easier to use a smaller, lightweight yagi.  They come in all
> sizes.  Here’s one example:
>
> https://www.amazon.com/gp/product/B008Z4I7WQ/ref=oh_aui_deta
> ilpage_o01_s00?ie=UTF8&psc=1
>
> -Scott
>
>
> On Dec 6, 2016, at 8:41 PM, Chuck McManis <chuck.mcmanis at gmail.com> wrote:
>
> In the US there is a company called Dish Network (satellite TV) they
> use a small dish antenna to talk to the satellites, it also makes a
> great starting point for a directional WiFi antenna. Remove the LNB
> that is normally in the antenna and tape a WiFi chip antenna at the
> focal point. You can then point quite accurately at various WiFi
> sources.
>
> <http://tse1.mm.bing.net/th?&id=OIP.M2844c9d84173dc5d1b923fe
> d7c9edf64o0&w=300&h=300&c=0&pid=1.9&rs=0&p=0&r=0>
> is a picture of one of these antennas.
>
> --Chuck
>
> On Tue, Dec 6, 2016 at 5:20 PM, Tamer Çelik <tamercelik at gmail.com> wrote:
>
> Hello,
> I am having a strange interference issue on my 2.4GHz WiFi network while
> 5GHz band works perfect.
> This might be coming from one of my neighbours.
> Just wanted to ask if its possible to use a "directional" antenna with
> HackRF and explore the area for possible source of interference?
> I am pretty sure on that something jamming 2.4GHz for random intervals.
> Any suggestions?
> Thanks!
>
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