WIFI DFing

[Terry N4TLF]

It is possible to DF if you have a good directional antenna, a wifi device that allows an external antenna, and you can program a version of DD-WRT (IIRC) into the device.  I have used both a beam and a dish to peak on specific wifi signals.  It helps to know what channel the wifi in question is on, and even better the SSID.  It’s been a while, but there is a mode in DD-WRT, or the HSMM/BBHN/AREDN firmware that shows you the SSIDs out there on what channels, and I think you can get signal strength, albeit slowly.  Or, use the software that Jacek mentions.

You can also use an old satellite TV antenna, with a modified feed in place of the original feed/LNB combo.  There are a LOT of instructions on how to modify them.  Realize that these antennas use an offset feed, so don’t “point” the antenna without taking that into account.

I have had good luck with both the Amazon wifi beam antennas ($25?), and the $50 parabolic dish on Amazon.  Mel (W4MEL) and I were using these to build a AREDN link between our two houses, as well as trying to get others interested in AREDN/BBHN here in Charleston a couple of years ago.  Unfortunately, there are not enough hams or high places here to make an AREDN network viable.
73, Terry, N4TLF

From: Jacek Radzikowski 
Sent: Wednesday, March 20, 2019 6:06 PM
To: Martin 
Cc: tacos ; Alex Fraser 
Subject: Re: WIFI DFing

Using regular radio for DFing a wifi transmitter is not such a good idea. The channels overlap, higher data rate transmissions use spectrum spanning several channels, and many stations transmit on the same frequency, so with a plain received you will hear a cacophony of sounds, making it almost impossible to find the station you're looking for. 

You will get much better results using a good wifi card with SMA connector (Alfa cards are great for 2.4G band) with a directional external antenna and airmon-ng from Aircrack-ng package to monitor signal strength for the station you are interested in.
Don't buy those cheap 2.4G yagis from ebay or amazon. They are junk. You'll get much better results with a home-made cantenna, orheck Andrew Mcneil's channel on youtube if you need some inspiration: https://www.youtube.com/channel/UCHqwzhcFOsoFFh33Uy8rAgQ

Regards,

Jacek
kw4ep


On Wed, Mar 20, 2019 at 5:18 PM Martin <dcmk1mr2 at gmail.com> wrote:

  WiFi features short packets.  You can tune in on an access point and hear the clicks.  You could try with a highly directional yagi or time of arrival rig.

  BTW Transmitter Hunting is highly recommended but is mostly VHF. 

  73 Martin W6MRR


  On Wed, Mar 20, 2019 at 1:55 PM Alex Fraser <beatnic at comcast.net> wrote:

    Is it possible to find a WIFI station with direction finding?


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