[aprssig] HackRF as SDR for ham use?

Greg D ko6th.greg at gmail.com
Sun Aug 3 14:43:13 EDT 2014


Hi Chuck,

Yeah, Wireshark and I are already good friends.  The problem is that one 
can only capture what the wi-fi interface can hear clearly, and often 
that's not where the problems are.  So integrating the RF spectrum view 
is what I'm after.

For those wanting to play with Wireshark with Wi-Fi, for example (and to 
keep it ham-related) diagnosing an ad-hoc network supporting a field-day 
operation, you can put many of the newer Wi-Fi adapters into monitor 
mode and capture down to the beacon level.  From a Linux root shell 
(sorry, I don't know if this is possible from Windows or Mac):

ifconfig wlan0 down
iwconfig wlan0 mode monitor
iw reg set 00
iw dev wlan0 set channel <channel> [HT20|HT40+|HT40-]
iw phy phy0 set channel <channel> [HT20|HT40+|HT40-]
ifconfig wlan0 up

Then aim Wireshark at wlan0 and you're set.  There are probably 
extensions for 802.11ac, but my laptop doesn't go there yet.

Sometimes you'll get a device busy error, in which case you're stuck - I 
haven't found a way around that.

Greg  KO6TH


Chuck Gooden wrote:
> Greg,
>
> To capture and decode Wi-Fi traffic, down load a copy of wireshark at 
> http://www.wireshark.org.  There is a link for a 802.11 packet capture 
> but it is expensive.  wireshark is a very good tool that I use at work 
> and is very full featured.  I have never tried it on a wifi connection 
> but it will probably work, and if it doesn't its free so it wont cost 
> you anything.
>
> Chuck
>
>
> On 8/2/2014 11:00 PM, Greg D wrote:
>> Hi John,
>>
>> Non-Ham related question...  Professionally, I work in the Wi-Fi 
>> area, and was also interested in being able to use the HackRF for 
>> capturing and decoding Wi-Fi traffic, as well as getting a better 
>> look at the RF environment (spectrum analysis).  Can this be done 
>> with the available (free) software?
>>
>> Sounds like a really interesting and fun conference!
>>
>> Greg KO6TH
>>
>>
>> John Gorkos wrote:
>>> I'm at BlackHat right now, and just finished the first day of classes,
>>> hands on, with Michael Ossmann and the HackRF.  I've barely had any 
>>> time
>>> with it at all.  It has extremely low transmit power, and is classified
>>> as "test equipment" to avoid all of the FCC legalities for type
>>> certification.  I can tell you I've gotten 20MHz of bandwidth samples
>>> out of it, into a Linux VM on my MacBook pro, and it seems to be pretty
>>> slick.  Tomorrow will be more hands on with the device, and a LOT of
>>> time in GnuRadio.  Obviously, based on the fact that we're at BlackHat,
>>> most of the concentration is on security and penetration. Things like
>>> finding unknown signal types in a very large chunk of spectrum, then
>>> locating and identifying those signals.
>>>
>>> BTW, Michael is a real genius at explaining SDR techniques and the math
>>> behind them.  At the beginning of the class, he passed out little green
>>> plastic slinkys with his company logo on them.  Today, about halfway
>>> through the afternoon session, he used the slinkys to explain how a 
>>> sine
>>> wave and cosine wave look the same, depending on whether you're looking
>>> at them from the imaginary or real number point of view, and that the
>>> slinky represents the longitudinal axis of time extending out of the
>>> paper, as you plot complex numbers on a two axis system. Freaking
>>> brilliant.   If you ever get the opportunity to go to one of his
>>> classes, you'd be a fool to decline.
>>>
>>> I'll try to provide more info about the device tomorrow.  I'm mentally
>>> and physically drained after a day of complex math.
>>>
>>> John Gorkos
>>> AB0OO
>>>
>>>
>>> On 8/2/14, 6:13 PM, Greg D wrote:
>>>> Hi folks,
>>>>
>>>> I see there's a new SDR receiver being built for the "hacker"
>>>> community:  http://hakshop.myshopify.com/products/hackrf
>>>>
>>>> They claim it's compatible with SDR#, so I wonder how well it will 
>>>> work
>>>> for the variety of digital ham radio purposes?  It's a little 
>>>> pricy, but
>>>> claims to cover 10mhz to 6 ghz, so that would cover through our
>>>> 5.65-5.925ghz allocation.  I don't know what the bandwidth is.
>>>>
>>>> Useful?
>>>>
>>>> Thanks,
>>>>
>>>> Greg  KO6TH
>>>>
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