[Hackrf-dev] Current, reasonably priced external clock?

Mon Nov 7 17:14:59 EST 2016

Mark,

The best ones you can find for a low price are, ironically, ones that are
synchronized via GPS.  Of course, if you're working on spoofing GPS -
that's not going to help.  The good news is that the HackRF can actually be
calibrated via software to increase the accuracy enough to fool _most_ GPS
devices.  Check out Wang Kang's "kalibrate" for HackRF, it should help you
get up and running.  Again, this will work for most GPS devices; phones can
be a bit trickier since they also use triangulation and crowd-sourced Wifi
mapping to establish location.

If the software doesn't work out for you - the cheapest way is to attach a
more accurate TCXO directly to your HackRF.  Check out Takuji Ebinuma's
TCXO modification- it's a part of his gps-sdr-sim project, which you can
use for the actual spoofing.  I've made this modification to my hackRF and
it works great!  I do have a portapack, however, and had to solder directly
to the bottom of the board.  It still fits in the case :)

As you are probably already aware, you need to VERY careful when spoofing
GPS, whitehat or not.  It's become such an integral part of our lives that
messing with it can have serious consequences.  I use a small antenna
(linked below) along with a 20dB attenuator.

- Adam Blanquart (overflow)

Kalibrate for hackRF
https://github.com/scateu/kalibrate-hackrf.

gpr-sdr-sim
https://github.com/osqzss/gps-sdr-sim

TCXO mod
https://github.com/osqzss/gps-sdr-sim/commit/d8eab7ede71168d131f3803d84d9bf8dbb34f4df

Antenna
http://www.digikey.com/product-search/en?keywords=TS.07.0113

In-Line 20dB Attenuator:
http://www.digikey.com/product-search/en/rf-if-and-rfid/attenuators/3539493?k=H12150-ND

That should get you going in the right direction (no pun intended).  I got
into the SDR world because I was interested in GPS spoofing, so if you have
any other questions, feel free to give me a shout...

On Mon, Nov 7, 2016 at 11:00 AM, Mark Lachniet <mark at lachniet.com> wrote:

> Who knew it would be so obscure.  I guess everyone is using nice desktop
> sized clock signal generators?
>
> I really want one that will run on 12v DC current if possible.
> Potentially to make a HackRF/Pineapple/TXCO clock combo that could run on
> the 12v of a car after I stuff it in the dashboard out of sight.  Maybe
> even with a cell phone/CAM+OBDii add-on for remotely fiddling with car
> telemetry.  It would be hilarious to prank someone so their car shuts down
> whenever they get near the local police department and then have their
> in-car GPS tell them they were at Starbucks or something.  (white hat PoC
> of course, no I would never actually do this to anyone  in production
> except maybe myself in an empty parking lot for yucks)
>
> -Mark
>
> On 11/7/2016 12:10 PM, Kevin Maxson wrote:
>
> I bought two of them. Neither worked. The seller didn't speak much
> English, couldn't give me specs, couldn't tell me a pin out. They offered
> to refund $8 of my $35.
>
> You want them? All yours.
>
> ./kevin
> 📱
>
> On Nov 7, 2016, at 10:58 AM, justin.broos <justin.broos at gmail.com> wrote:
>
> Ebay,  Amazon have one that ultimately ships from some Chinese
> manufacturer off of aliexpress / alibaba . The plug in module is $20 iirc.
> The description claims to output a 1ppm 10mhz source but no info about the
> tcxo is listed so who knows; I have equipment at work that could measure
> but don't have the knowledge of setting it up.  If you do opt for this
> route,  it would be interesting to know if the module works as advertised
> as I'm still on the fence to buy it .
>
>
>
> Sent from my T-Mobile 4G LTE Device
>
> -------- Original message --------
> From: Mark Lachniet <mark at lachniet.com>
> Date: 11/3/16 13:04 (GMT-07:00)
> To: hackrf-dev at greatscottgadgets.com
> Subject: [Hackrf-dev] Current, reasonably priced external clock?
>
> Hello all, my apologies for asking a question that I know has been asked
> in months past, but it has been long enough that there might be new
> options, and some of the previous answers seemed more towards
> development than plug-n-play.
>
> I'm very new to SDR (and radio in general) and just learning the ropes.
> I was trying to do a PoC on the GPS spoofing using my HackRF and had
> limited success.  I got my Nuvi to lock in randomly a little bit but no
> real love.  I read that another person needed the external clock in
> order to get good results.  I'd like to buy a simple and inexpensive one
> that is fairly plug-n-play.  Can anyone recommend a specific model and
> vendor to purchase from that doesn't require such tasks as soldering?
>
> I've got a nice long list of other questions but as I'm new and ignorant
> I'll hold onto those for a while on the off chance I can figure them out
> and appear less needy in the long run :)
>
> Thank you for your time and consideration,
> Mark
>
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>

-- 
ADAM BLANQUART | ablanquart at gmail.com |
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