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silent 30C3 preroll titles
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applause
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Travis Goodspeed: First I need
to apologize for typesetting this
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in OpenOffice. I know that the
text looks like a ransome note.
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But that’s what happens
when you don’t use LaTex.
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I’d also like to give a shoutout
call, mallnarf (?) is here,
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and our Dinosaur rock band.
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laughs, applause
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We’re a Christian rock band – we’re
called ‘Jesus lives in the ISS’ and
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we know that he is always watching us,
but we think that it’s easier for him
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to hear our prayers when
he’s, you know, in an orbit
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that passes over us. So we need to use
orbital tracking to know when to pray!
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laughter
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As I’m sure you can guess I’m not
recognized as a legal minority religion
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in Germany. I’d also like to thank skytee
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and Fabienne Serrière and Adam Laurie
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and Jim Geovedi for some
prior satellite tracking work,
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and the scooby crew (?) at Dartmouth
College for all sorts of fun
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whenever I bounce out there.
This is the mission patch
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of the Southern Appalachian
Space Agency (SASA).
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applause and cheers
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This was drawn by Scot Biben (?) and there are
a few pieces of my people’s native culture
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that I need to point out here. On the
right the little Dinosaur type thing
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with his finger going out, you might
call him E.T. but we call these things
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‘buggers’. They are like this tall, and
they are green and that’s why the man
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on the left has a shotgun.
laughter
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Because he doesn’t want to be abducted.
You got a satellite dish in the middle
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and it’s sitting on sinter blocks because
that’s also a piece of my people’s
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native culture. There’s a moonshine
still in the background.
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That’s kind of like Waldcubbet (?), you
make it at home and from corn.
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And then there’s the mountain… a piece,
it looks like there are snowpeaks
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on those mountain tops. But our mountains
aren’t tall enough to have snow.
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These are actually that we’ve blown off
the lids of the mountains for coal mining.
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Which is another piece of
my people’s native culture.
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And at the top, in space you can see
the ISS, and you can see a banana,
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and you can see what I think is a bulb.
This is to signify space trash.
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I mean there’s a lot of stuff up there.
And, you know it’s symbolism that matters
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in these things, you know?
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At BerlinSides, in May of 2012
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I did a lecture on reverse
engineering the SPOT Connect.
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The SPOT Connect is a litte
hockey puck type thing
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– this is what it looks like.
And these things are great.
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It weighs a bit more than your cell phone
but it runs off of a couple of batteries,
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it connects to your phone by Bluetooth.
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Originally these were emergency locator
beacons. So if you’re going hiking…
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have any of you seen the movie where
the guy has to cut off his arm
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with a dull knife? If you’re hiking and
you don’t want that same experience
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you buy one of these things. And
then there’s an emergency button
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you can push that transmits your
GPS coordinates by satellite
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to rescue workers. But that was boring,
so they had to add social media.
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laughs, laughter
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So in addition to keeping you
from chewing off your own arm
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this device will also allow you to
tweet and make Facebook posts.
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laughs, laughter
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The idea is that as you’re running…
here I’m crossing the Schuylkill River
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in Philadelphia and the Android
phone on the left is making a post.
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And I did an article on reverse-
engineering the Bluetooth side
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of these things. Because… I use a weird
brand of phone that Microsoft killed off,
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and I’m terribly bitter about it. But
I also figured out the physical layer.
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And that’s what this diagram shows.
This transmits at 1.6125 GHz.
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And it sends a pseudo-random stream, so
each one of these zeros is a long chunk
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where it’s bouncing back and forth
between 2 different frequencies.
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And the same for the ones.
But the way that the pattern works
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is that it switches the signal whenever
it is going from the 0 signal
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to the 1 signal. And internally, there are
these little pops that you can actually
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identify on a Software Defined Radio
recording. And this is how you can
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reverse-engineer the signal that
the SPOT Connect is sending up
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to its satellite network.
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Everything is clear text on this.
And it’s completely unencrypted.
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It just has your serial number, your GPS
coordinates, and a bit of ASCII text.
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So if you listen on this frequency and
you have the correct recording software
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you can actually watch all of the SPOT
Connect messages that are transmitting
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up from your location. And this would be
great except that this is designed for
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hiking in areas where there’s no cell
phone service. So having an antenna
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on the uplink frequency is kind of
useless. You know you would actually
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have to go out to a national park, find
some guy who is about to chew his arm off,
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and then you could listen to his uplink
where he is like tweeting: “Hey, I’m gonna
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chew my arm off”, you know?
laughter
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So that’s great as a proof of concept
but it’s not really anything practical.
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The current state of that was that I knew
the protocol and I could sniff the uplinks.
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But I wanted to sniff the downlinks. So
it’s easy for me to get the thing that
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goes up to the satellite. But what I wanted
was what comes down from the satellite.
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And that requires a satellite dish. But
a geo-stationary dish isn’t good enough
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because the satellites that run this
network – there are a lot of them,
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it’s called the Globalstar network,
they fly really low across the earth,
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and they fly across the earth in very
tight, very fast orbits. So they’ll move
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from horizon to horizon in 15 to 20
minutes. Which means that you either need
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like a sweat shop army of kids
trying to aim the satellite dish
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as it’s going across or you need
to make it computer-controlled.
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Stepping back from the SPOT
Connect for a little bit, and
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discussing some prior research.
Adam Laurie did some work
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with geostationary satellites.
These are the satellites that stay
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in one position in the sky.
He gave two sets of talks
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– one in 2008 and the second in
2010. And he used a DVB-S card
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connected to a satellite dish with
a diseqc motor, so that it could move
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the satellite dish left and right in order
to scan a region of the horizon.
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His tool is publicly available,
it’s called satmap.
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You can grab it at this URL.
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And then after he finds a signal he has
a feed scanner. Normally when you use
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Satellite TV you provider gives you
a listing of the frequencies, and
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your provider gives you an exact orbital
position to aim your satellite dish at.
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But Adam’s tool allows you to scan to
see which frequencies are in use and
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which protocols are in use, once
you’ve correctly aimed your dish.
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And he also describes a technique
for moving your dish left and right
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while doing this in order to
identify where the satellites are.
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This recording here is from
a re-implementation that I made
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of Adam’s work, in order to
catch up with it. In this diagram
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the x-axis – because you move left
and right – that shows the azimuth,
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that shows how far left or right my
satellite dish has moved. And then
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the y-axis shows the frequency. And
all of these dots are strong signals.
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So every vertical bar in which you see
chunks of frequencies, that’s a satellite.
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But these stay in the same position. So
it’s easy for me to repeat this experiment.
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It’s easy for me to re-run it, and to find
the same satellites in the same position.
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It’s easy to debug this.
But it can’t move in elevation.
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This diagram is actually
a very small slice of the sky.
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We’re looking at a single line,
maybe 10 degrees across.
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Maybe only 5 degrees across.
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So hacking Ku-band – the television
satellites – has the advantage
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that you can use cheap standardized
hardware. I bought one of these DVB-S cards
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in Mauerpark, in Berlin for 3 Euro. You
can use standardized disecq motors,
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you can buy them at a satellite TV shop.
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TV signals come with video feeds
so you can actually see pictures.
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There was a scandal about 4..5 years
ago where they were finding
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drone [control] feeds that were being
bounced across these satellites.
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In the nineties it was very popular to
listen to the sort of unedited sections
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of interviews, when people would
be interviewed over a satellite,
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before Skype and such
things became options. And
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there are also networking signals here
using TCP/IP packets. So you can actually
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turn your DVB-S card into
a promiscuous ethernet adapter,
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and start sniffing all of the traffic that
comes across. This is also a great way
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to get free downlink bandwidth. Because
you can just flood packets at an address
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that, you know, will be routed to
you, or several addresses, and
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then you sniff it out as the
legitimate receiver ignores them.
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But it also has some disadvantages. It
only works for geostationary satellites.
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If the satellite is not staying in the
same position relative to the ground
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then you can’t track it. Your
dish also moves very slowly.
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And it only moves left and right.
It won’t move up and down.
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And you’re limited to standardized
signals. So while it’s great that you get
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video and TCP/IP you’re never
going to get anything weird.
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You’re not gonna get any mobile
data, you’re not going to get any
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Brazilian truck-drivers – we'll
get to those in a bit. laughs
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I misspoke, you actually will get
Brazilian truck-drivers in this.
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So I bought a satellite dish. One of the
best things about living in America is
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that you can buy industrial
hardware cheap as dirt on ebay.
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I know things aren't likely used to being
a cat bite to (?)(?) human children anymore.
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But this satellite dish here on
the left – the one in the radome –
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that's my dish. And to the right,
that's the boat that it came from.
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applause
laughs
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This came from a military ship.
But the dish itself is also available
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for civilian use on very large yachts.
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The dish itself is a Felcom 81 and it
was intended for use with a network
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called Inmarsat. Inmarsat allows
for telephone connections,
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and also data connections when you're on
a boat. So if the crew wants to call home
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or wants to go to AOL Keywords
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or whatever was popular back when
this was common they could do that.
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And the dish was designed to sit
at the very top of a ship's mast.
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The reason why is that at the top of
the mast there aren't any obstructions
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– it has a clear view of the sky in all
directions. But there's a complication
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with being on the top of the mast. Which
is that the ship is rocking beneath you
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and you're moving more
than the rest the ship.
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So they have stepper motors
for azimuth, elevation and tilt.
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And then they have spinning gyroscopes.
Back before the iPhone there was
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this dark, dark time when
gyroscopes actually spun.
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And this is the sort of gyroscope that
it has. It actually has 4 of them so
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that it can measure its movement.
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And then it has a control computer. So the
idea is that the dish itself can be moved
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while remaining absolutely stable
with regard to the gyroscopes.
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So it compensates for the rocking of
the ship beneath it as it's targeting
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a stationary satellite.
In America this costs 250 dollars
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but it's electronics equipment, so while
you think that would only be a 180 Euro
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it's more like 2500. And that's before
import duties and it being impounded.
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We also have this lovely culture in which
people love excuses to use their trucks.
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So the guy that I bought this from offered
to deliver it to my home for only $200.
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It was an 11-hour drive.
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But if you wanted this you'd have to
bring it back in your carry-on luggage
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and that could be awkward.
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I got this dish and I decided I had
to do something with it. So I created
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the Southern Appalachian Space Agency.
I'm from the state of Tennessee,
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formerly known as the State of Franklin
until North Carolina invaded us.
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It's ok, I know Europeans suck at history.
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laughs
laughter and applause
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Now I'm trying to think of how to show
you on a map where Tennessee is
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without having a map. But, you know, it's
okay, I know you suck at geography
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and will forget it soon (?)
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From audience: It's very
near Texas, to the north.
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Travis: Texas is our first colony. But
it's actually a decent drive to the east.
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Due east (?). You don't
actually have to go it anyways.
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So what I did was I took these motors
which were designed to be able to move
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the satellite dish to compensate
for the rocking the ship and
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I re-purposed them to track through
the sky while the ground is stable.
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We don't have very many earthquakes in
Tennessee. The last one that we had
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made rivers run the wrong direction.
But it's okay – it's a geography thing.
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laughs
So this allows me to track things
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that are moving through the sky.
But it doesn't actually matter
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where they're moving in the sky because
that's just a software problem.
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So in addition to tracking objects that
are in low-earth orbit by a software patch
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I can also track things that are in deep
space. It's not much harder to track
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deep space probes or stars than it
is to track items in low-earth orbit.
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And then I added a software defined radio
which allows me to record a signal now
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and then demodulate it later.
Which is necessary if you intend
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to reverse-engineer a signal. Because
a lot of the downlinks from these satellites
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are completely non… completely
undocumented. And being able
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to tune in to the right frequency is only
half of it. You also need a recording
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of sufficient quality that you can
reverse-engineer it after the fact.
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We're sort of spoiled by software
defined radios in that when doing
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software defined radio work we usually
have a very good signal to work from.
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So having high quality signals for later
reverse-engineering is necessary.
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I really wanted to be able to identify
undocumented downlinks for low-earth orbit
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in the same way that we already
do this for geo-stationary orbit
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using tools like the ones that Adam
Laurie and Jim Geovedi made.
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So I built a software framework as
a collection of Python daemons.
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And these run across a home
area network in my house.
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There's a Beaglebone inside of the Radome.
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And an x86 server in the house. Or AMD64,
whatever the kids call it these days.
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And then I used Postgres for coordination.
So that all of these daemons can talk
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to each other without… without me really
caring which machine they're on.
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So for maintenance I can have my
laptop pretending to be the dish,
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and I can have stepper motors on my desk,
and I can watch them spin, and I can even
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make a model of the dish and swap these
components in and out without the rest of
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the network being confused. This also
allows for sequal (?) injection attacks to
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physically move my dish. Which is why the
Sassin (?) network is not on one of those
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fancy WEB 2.0 things. Because of you could
inject, say, “UPDATE target SET name=
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'VOYAGER 1'”. Then my dish would physically
move and start tracking Voyager 1
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through the sky. Voyager 2
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doesn't actually come into the sky because
of my position in the Northern hemisphere.
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So, it's okay, I know you suck at
geography. But Voyager 1 is going up,
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and Voyager 2 is going down.
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There's a Realtek Software Defined Radio
for the radio reception. Although
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these things are garbage. So I'm in the
process of replacing this for the HackRF.
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There's also an EiBot board for motor
control. We'll get back to that in a minute.
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And there's an Inertial Measurement Unit
from VectorNav which actually measures
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using the fancy MEMS gyroscopes and
a MEMS compass how I'm moving.
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This isn't accurate enough to target
the dish, so I'm still counting steps
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to move the dish. But it is accurate
enough to tell me when my belts
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have broken. Or when I'm up
against the physical obstruction.
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This is skytee helping
me out with the dish.
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He's zip-tying it. Because, you know
we know everything about duct tape
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where I come from, but we know nothing
about zip ties. So I had to bring in
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a German engineer.
laughter
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We call him a Gerry wigger(?)
but, you know…
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This is the satellite dish itself. And you
can sort of see in this photograph
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where we've strapped on the equipment.
There's like an embillica (?) cord.
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Or more like a spinal column that actually
runs up the back of the dish. So we just
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added new cables onto that line.
And then zip-tied them in place.
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And skytee came up with all these
crazy ideas like that we should use
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chains and zip-ties to make sure that the
cables don't tear themselves out. And
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that worked tremendously well in practice.
So, as this thing spins around,
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by the original design there's a ring
connector that all of the signals
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go through. That all of the networking
goes through. That all of the rest
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goes through. And that worked in the
nineties because it had no reason
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to send anything faster than 9600 baud.
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But with the modern signals going across
it I need 100MBit/s or even GB ethernet,
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that's not enough, I need more than
two wires. So there's a cable that comes
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across it, and then I rely on the
software to keep it from wrapping
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that cable around itself. So it can only
move, say, 400 degrees around.
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But that's still more than a full circle.
So by stopping halfway and moving back
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I can prevent it from getting snagged (?).
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We've got the Beaglebone on the left,
in the middle there's a USB hub
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and on the right is the motor controller.
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The Beaglebone runs Debian Linux and
takes care of sending the software defined
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radio recordings over the network. It also
takes care of updating the motor positions
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to be the ones that the database
declares should be current.
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The stepper motors themselves are the
originals that the dish was designed with.
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And they're running to an EiBot Board.
The EiBot board was intended
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for plotting on Easter eggs
laughs, laughter
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I feel, you know… is that neat?
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laughs
applause
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So you can actually aim a satellite dish
that's as tall as you are, with of these
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fancy motors using less sophisticated
equipment than what's used
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in a 3D printer. Don't panic, though.
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It's a hell of a lot more
reliable than a 3D printer.
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But we needed some sort of backup in
addition to the inertial measurement unit
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telling us when the device
had snagged itself.
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It would also help to have
a visual queue. Because
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the satellite dish sits in Tennessee, and
while I love my home town, and, you know
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I'm very proud of being Tennesseean it's
also a long way to travel when you need
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to re-orient the dish. Using an
accelerometer it's easy enough
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to correct the elevation. Because you can
use the accelerometer as a level, and
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you can use that to tell how high up the
dish is pointing, at an absolute scale.
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But the compass isn't very accurate. So
instead, as a backup we have a webcam
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that's taped to the top. Taping
is my people's native culture.
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We have it taped to the top, and then
it's pointing backwards. So this gives us
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like a rear view camera,
from the dish's position.
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So as the dish sits
inside of its radome…
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– junk cars in the yard are also
my people's native tradition!
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laughs, laughter
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So the dish sits there next to
my brother's Toyota Supra.
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And that thing, you know,
that thing flies as soon as it gets
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an engine put back in it.
laughter
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So it sits there and it's moving but
externally you can't see where it is.
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Which means that I can't call my family
in Tennessee and blackmail them into
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- yet again - looking at my dish to tell
where it's pointed. There are bolts
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that hold this down. It takes half an hour
to remove the lid, another half an hour
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to put it back on.
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So instead we took the radome…
that's Frank, he's my cat.
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Give a “Cheers!” for Frank!
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applause and cheers
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Yeah, we had such a great time with Frank.
And we never knew that she was pregnant.
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If you happen to need kittens and wanna
pay the custom's fees I'll hook you up!
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So then we took tape and ran tape
down the edges of the radome,
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and then marked it. So from the markings
you can tell which clock position
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the back of the satellite dish is pointing
at. So if you point the dish towards 12:00
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you know that you're roughly at 6:00,
so you know that it's pointing South.
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And then you can sort of scan the sky
for a stationary target, and navigate
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off of that, to recover your position.
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Software-wise… remember, the
whole thing runs through Postgres,
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so I just tunnel the Postgres over SSH,
and then I wrote a Python client
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that displays the satellite positions
and the satellite state in PiGame (?).
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This is intended for making those games
where you see the rabbit and the rabbit
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jumps on the other rabbit. But it… works!
And it works perfectly well enough
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to target the dish. Because all that this
software has to do is plot the positions
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of the satellites, and give orders back to
the database when I click on a satellite
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or click on a position.
It can also display stars.
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So the red items are satellites which are
not selected. The green item is GOES3 (?)
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which is the satellite that I'm targeting.
And then the white items are
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stars in the sky. Now this is
a plot in which the azimuth
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is on the X axis, and the elevation is on
the Y axis. But I can also arrange it
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into a polar plot. Which sort of gives me
an upside-down view of the satellite dish
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looking at the sky.
I doubt you can read it but
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just above the green circle in the center,
that's Polaris which is the North star.
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It's also weird because, you know,
working on this, you know, I thought
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that I got really good at astronomy
until I realized that I only knew
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what the stars looked like during the day.
laughter, laughs
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And it being PiGame (?) you can
actually run it on a mobile device.
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So the same client that runs on my
laptop can also run on my Nokia N900.
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laughs
applause
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A significant portion of the GUI client for
this was written while stuck on the U-Bahn,
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connected over 3G, SSH through
and just using emacs on the phone.
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laughter, laughs
applause
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If you're one of those people who needs to
complain about the N900 being too old,
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it also runs on the N9.
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And then you can take the data out of this
and run it through scientific software.
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In addition of the software defined radio
recordings themselves being dumped out
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to a text file or a binary file on disk
you can also dump out things like
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the received signal strength indicators
(RSSI). So this is a screenshot in which
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I'm identifying different satellites that
I've seen in the sky based upon
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their downlink signal peaks. You can see
the noise floor there, at the bottom,
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and then there's a rather strong signal on
the left. And a weaker neverware (?) signal
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on the right. Now, the
daemons that build this up…
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you need an orbit prediction daemon.
Because you need to know
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where the satellites are and where
they're going, and where they will be
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by the time you get to them.
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You need to update the orbits themselves.
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LEO satellites are described in TLE files,
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these are called 'Two Line Entry' and
they're called 'Two Line Entry' because
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they're three lines long.
laughter
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These were originally used by NORAD for
inter-continental ballistic missile tracking.
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And because a ballistic missile
is basically in orbit, it's just that
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that orbit happens
to collide with the earth.
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But this format isn't terribly accurate
for satellites that adjust their own orbit.
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So anything that has fuel, or has engines,
or changes mass will vary its position.
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And this also doesn't account for drag.
Because, you know, the missile itself,
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you know it goes up it goes down, it's
not orbiting enough for the light drag
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in the upper atmosphere to matter. But for
a satellite it does. So these Two Line Entries
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will work for a matter of days or maybe
a couple of weeks. But they don't last
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longer than that. So you need a daemon
that grabs the new files from spacetrack (?).
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And this is just a matter of like
a recursive WGET, and then
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parsing the files. And that still needs
to be done. You also need motor control,
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because you need to move the dish
physically to track your target.
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You need input for the Inertial
Measurement Unit. This comes over
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a low voltage serial port. And then
you need radio daemons to handle
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spectrum analysis or downlink recording.
And these you'll have several of them,
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you have to swap them out. So you'll begin
by using the spectrum analyzer to identify
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that your aim is accurate, that you're
accurately tracking the targets
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well enough to get a recording from
them. And then after that you begin
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to take software defined recordings off
them. And, eventually, you might have
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a standalone application that parses
what you're receiving. Such as
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the Osmocom guys did with OpenGMR.
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So for orbit prediction I began
with a DOS program that had been
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ported to Unix, called 'predict'.
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And this worked, but it's garbage.
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It only supports 20 satellites plus the
sun, the moon, Venus and Mars.
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But no other planets because it's
designed for astronomy photographers
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who want to get a picture of something
as it comes over the horizon. You know,
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I need to track hundreds of targets and
then write a script to opportunistically
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pick the ones that I want to record.
Because otherwise you have to like
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set an alarm clock for the half-hour pass
in which you can play with something.
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That software does allow you to query the
results by UDP, though. So you can just
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send it a flood of request packets,
then it will flood back with the data
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you're looking for. So I switched to
a library called PyEphem which allows you
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to track hundreds of birds. It has no
UDP nonsense. It will also calculate
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satellites, planets and stars.
And the really nifty thing about this
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is that you tell it… you know, it being
a library you tell it when to update
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the individual object that you're
interested in. So you can update
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objects that are out of view or
uninteresting more slowly
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than the ones that you care about.
So I managed to track every single item
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in geo-stationary orbit. This thick
ring here is the clarke-belt(?)
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of all satellites in geo-stationary orbit,
as viewed from my Southern horizon.
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applause
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The Two Line Entry files you can get
freely from CELESTRAK.COM.
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So this is just a simple script that
grabs them and then inserts them.
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And the prediction daemon will actually
select them as it is loading up.
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Because all inter process communication is
running through this Postgres database.
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And this daemon can be moved to
a different machine if I needed
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more computing power, or anything
like that. The motor control demon…
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well, the Eibot board is designed to take
stepper motor commands. It shows up
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as USB Serial device on Linux. So as
I plug it in to the Beaglebone it appears
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as /dev/ttyACM0. And the baud rate doesn't
matter. Because this is a USB device.
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You could then send it simple commands.
Like 'SM,3000,500,-400' means that I wanna
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move a stepper motor for 3000 ms. I want
the first motor to move 500 forwards,
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that's UP, and the second one to move
400 LEFT which is backwards 400 steps.
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And then it will count that out, and
then it sends me back an OK.
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If I want to disable the motors, I send
'EM,0,0'. This allows the motors to be
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freely spun. Because normally a stepper
motor will physically hold its position,
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you need to turn them off in
order to slide the dish around.
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'EM,1,1' will enable both motors
in 1/16-of-a-step mode.
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Stepper motors can do fractional
steps because they're
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holding themselves in position.
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You can see the motors themselves
with the belts and the geartrain.
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This thing on the right would probably
be illegal for me to turn on.
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The thing on the right is a 250 W
amplifier. laughter
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The stepper motors themselves just have
six wires. In a lot of 3D printer type stuff
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they ignore the middle two. So you just
drop off the middle two wires, you run
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the other four to your stepper
controller, and you're good to go.
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The belts and stuff need to be measured
in order to figure out exactly
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what the georeduction (?) is. Because you
need to know how many steps form a degree.
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The IMU unit, this Vectornav VN100 (?),
it's a MEMS gyroscope and accelerometer
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and a compass in a single box.
It costs $500 which was
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99:59:59,999 --> 99:59:59,999
more than all of the other
equipment put together.
420
99:59:59,999 --> 99:59:59,999
The compass is confused by the stepper
motors because the compass is measuring
421
99:59:59,999 --> 99:59:59,999
magnetic fields. So you need to
mount this physically as far away
422
99:59:59,999 --> 99:59:59,999
from the stepper motors as possible. And
the gyroscope is confused by motor jerk (?)
423
99:59:59,999 --> 99:59:59,999
which is a shame because stepper motors
work as a series of jerks (?) rather than
424
99:59:59,999 --> 99:59:59,999
as a single consistent motion. And the
accelerometer is confused by gimble lock,
425
99:59:59,999 --> 99:59:59,999
so you have to switch it to
a quaternian (?) mode in order to get
426
99:59:59,999 --> 99:59:59,999
consistent values out of it. And if I had
to do this over again I'd really try
427
99:59:59,999 --> 99:59:59,999
to drop this piece of garbage. But it's
a lovely technology when it works.
428
99:59:59,999 --> 99:59:59,999
some laughter
429
99:59:59,999 --> 99:59:59,999
Now for position calculations, the
elevation itself comes from the IMU.
430
99:59:59,999 --> 99:59:59,999
The azimuth comes from the motor daemon.
This is because the accelerometer
431
99:59:59,999 --> 99:59:59,999
can very accurately tell which way
the earth's gravity is pulling it
432
99:59:59,999 --> 99:59:59,999
whereas the accelerometer has to integrate
jerks (?) over time in order to figure out
433
99:59:59,999 --> 99:59:59,999
its position. So the
accelerometer will drift
434
99:59:59,999 --> 99:59:59,999
and the compass will be confused by the
magnetic fields while the elevation is
435
99:59:59,999 --> 99:59:59,999
just a single accelerometer
that doesn't drift.
436
99:59:59,999 --> 99:59:59,999
And the IMU will become
a backup for these things
437
99:59:59,999 --> 99:59:59,999
in order to figure out how to make
it reliable. But at the moment
438
99:59:59,999 --> 99:59:59,999
the position measurement is infinitely
more reliable. The tilt motor
439
99:59:59,999 --> 99:59:59,999
I'm not using at present because on
a ship that's rocking it's necessary
440
99:59:59,999 --> 99:59:59,999
to tilt the dish. On a satellite dish
that's staying still the only useful
441
99:59:59,999 --> 99:59:59,999
tilting the dish is so that you can follow
the arc of a satellite through the sky
442
99:59:59,999 --> 99:59:59,999
by only moving a single motor.
Photopgrapher do this when they're
443
99:59:59,999 --> 99:59:59,999
trying to get long exposures of moving
satellites. At the moment my software
444
99:59:59,999 --> 99:59:59,999
doesn't support this feature. But
if it turns out to be necessary
445
99:59:59,999 --> 99:59:59,999
to get higher quality
recordings I might add it.
446
99:59:59,999 --> 99:59:59,999
There are radio daemons. The
first is a spectrum analyzer.
447
99:59:59,999 --> 99:59:59,999
This just measures the signal strength
on each frequency. And it does it by the
448
99:59:59,999 --> 99:59:59,999
power spectral density function.
449
99:59:59,999 --> 99:59:59,999
And the strength itself will
vary with the position error.
450
99:59:59,999 --> 99:59:59,999
So this allows you to figure out how
far off you are by sort of testing,
451
99:59:59,999 --> 99:59:59,999
by overshooting just a little bit,
or undershooting just a little bit
452
99:59:59,999 --> 99:59:59,999
to center on your target. The downlink
recorder dumps the IQ values
453
99:59:59,999 --> 99:59:59,999
in the software defined radio
directly to an NFS share,
454
99:59:59,999 --> 99:59:59,999
which can later be decoded and
read and reverse-engineered.
455
99:59:59,999 --> 99:59:59,999
We've got a whole table of spectrum
data. And then I plot that in a tool
456
99:59:59,999 --> 99:59:59,999
called Viewpoints which NASA releases
for dealing with giant scatterplots
457
99:59:59,999 --> 99:59:59,999
in multiple dimensions. Each view takes
two dimensions, and it's tons of fun.
458
99:59:59,999 --> 99:59:59,999
The client GUI is this PyGame. I have
Postgres for communications, and
459
99:59:59,999 --> 99:59:59,999
the server does all the heavy lifting,
so the Beaglebone itself never has
460
99:59:59,999 --> 99:59:59,999
to do anything complicated with
regards to software defined radio.
461
99:59:59,999 --> 99:59:59,999
This is also about these faint blue lines
are positions at which I've seen
462
99:59:59,999 --> 99:59:59,999
particularly strong signals in order to
identify which satellites are active
463
99:59:59,999 --> 99:59:59,999
and which ones are inactive.
Because satellites die over time.
464
99:59:59,999 --> 99:59:59,999
And particularly useful targets we're
reverse-engineering are satellites that are
465
99:59:59,999 --> 99:59:59,999
out-of-commission or outdated.
I'm running out of time by these markers.
466
99:59:59,999 --> 99:59:59,999
Does that mean that we're skipping
questions, or does that mean that
467
99:59:59,999 --> 99:59:59,999
I need to be off the stage?
mumbling to stage
468
99:59:59,999 --> 99:59:59,999
Not having Q&A, okay. So today I get
accurate tracking of satellites.
469
99:59:59,999 --> 99:59:59,999
And this thing can run unattended 24h
a day for months without maintenance.
470
99:59:59,999 --> 99:59:59,999
Like I said: it's nothing like a 3D printer.
laughter
471
99:59:59,999 --> 99:59:59,999
It takes software defined radio
recordings, it can provide maps
472
99:59:59,999 --> 99:59:59,999
of views of different
satellites in the sky.
473
99:59:59,999 --> 99:59:59,999
The next step is I want to publish
a 'port scan' of the entire sky.
474
99:59:59,999 --> 99:59:59,999
So which frequencies are in use on which
birds, for every bird that ever comes
475
99:59:59,999 --> 99:59:59,999
above Tennessee, on every
downlink that fits my antenna
476
99:59:59,999 --> 99:59:59,999
as well as a database of software
defined radio recordings. If anyone
477
99:59:59,999 --> 99:59:59,999
would care to donate a truckload
of disks – that might be handy.
478
99:59:59,999 --> 99:59:59,999
I'd also like to make other ground
stations. The software that I've written
479
99:59:59,999 --> 99:59:59,999
ought to be portable to new hardware.
So there's nothing that should keep you
480
99:59:59,999 --> 99:59:59,999
from being able to port this to run on
your own dish. And I have a large yard,
481
99:59:59,999 --> 99:59:59,999
so I could conceivably have
a dozen of these things.
482
99:59:59,999 --> 99:59:59,999
Another way that you can do it, and
the way that it's traditionally done
483
99:59:59,999 --> 99:59:59,999
for, say, KEEP (?) satellites is having
Yagis or other loosely directional antennas
484
99:59:59,999 --> 99:59:59,999
in order to receive the signals.
I went with a dish because I wanted
485
99:59:59,999 --> 99:59:59,999
more selectivity. I wanted to be able to
get reverse-engineerable recordings
486
99:59:59,999 --> 99:59:59,999
rather than intentional ones for which
I already knew the downlink protocol.
487
99:59:59,999 --> 99:59:59,999
So this is my van, my van is amazing.
488
99:59:59,999 --> 99:59:59,999
applause
489
99:59:59,999 --> 99:59:59,999
Thanks to Nick Farr. I had a bit too
much to drink in Montreal and
490
99:59:59,999 --> 99:59:59,999
I called Nick Farr and I said: “Nick,
I want a dukw”, like these amphibious
491
99:59:59,999 --> 99:59:59,999
troop transport vehicles. And Nick
said: “Sorry, I can't get you one but
492
99:59:59,999 --> 99:59:59,999
you want a news-van!” And I said:
“Hell yeah, I want a news van!”
493
99:59:59,999 --> 99:59:59,999
So – this pole in the background, that's
not a lighting pole. That's actually
494
99:59:59,999 --> 99:59:59,999
part of the van.
laughter
495
99:59:59,999 --> 99:59:59,999
This is the antenna retracted. This mast
goes up 20 m by pneumatic power.
496
99:59:59,999 --> 99:59:59,999
There's an air compressor in the back.
Here is the control panel,
497
99:59:59,999 --> 99:59:59,999
there's an air-conditioned
office in the middle.
498
99:59:59,999 --> 99:59:59,999
laughter, laughs
499
99:59:59,999 --> 99:59:59,999
This has four 19" server racks as well
as some A/V equipment that was left over.
500
99:59:59,999 --> 99:59:59,999
I was particularly excited about the
video monitor which supports PAL
501
99:59:59,999 --> 99:59:59,999
which you folks are familiar with,
NTSC or “Never The Same Color”
502
99:59:59,999 --> 99:59:59,999
which is my people's native culture…
laughter
503
99:59:59,999 --> 99:59:59,999
But most importantly, it does SECAM,
the system essentially contrary
504
99:59:59,999 --> 99:59:59,999
to the American method.
laughs
505
99:59:59,999 --> 99:59:59,999
laughter and applause
506
99:59:59,999 --> 99:59:59,999
So in addition to my radio equipment
I'm adding my Soviet PDP-11 which was…
507
99:59:59,999 --> 99:59:59,999
laughs
…and that's not a joke. I have a Soviet
508
99:59:59,999 --> 99:59:59,999
PDP-11 thanks to the kind folks at the
Positive Hacking Days conference.
509
99:59:59,999 --> 99:59:59,999
This is the control panel,
and that's my talk!
510
99:59:59,999 --> 99:59:59,999
applause
511
99:59:59,999 --> 99:59:59,999
Herald: Thank you so much.
There actually is time for Q&A now.
512
99:59:59,999 --> 99:59:59,999
Travis: Well, first I'd like to introduce
you to my cat. If we could go back
513
99:59:59,999 --> 99:59:59,999
to the prior image. This is Frank!
We didn't know it at that time, but
514
99:59:59,999 --> 99:59:59,999
Frank was not dead when this picture was
taken. If you'd like kittens get in touch!
515
99:59:59,999 --> 99:59:59,999
Okay. Are there any questions?
516
99:59:59,999 --> 99:59:59,999
Question: Great talk. What's the most
interesting signal you decoded so far?
517
99:59:59,999 --> 99:59:59,999
Travis: At the moment I'm sort of stuck
at the L band range. Because of filters
518
99:59:59,999 --> 99:59:59,999
that I have yet to remove. So everything
gets attenuated, and becomes annoyingly
519
99:59:59,999 --> 99:59:59,999
quiet outside of the 1.5 ..1.6 -ish range.
520
99:59:59,999 --> 99:59:59,999
The Globalstar network is what I'm
most interested in targeting next.
521
99:59:59,999 --> 99:59:59,999
I can't wait to see what
people are tweeting
522
99:59:59,999 --> 99:59:59,999
while they should be enjoying nature.
523
99:59:59,999 --> 99:59:59,999
Herald: Is there a question
from the internet?
524
99:59:59,999 --> 99:59:59,999
Signal Angel: Yeah, the internet has
many questions. So first one was:
525
99:59:59,999 --> 99:59:59,999
Is there really no authentication or
encryption on the Q band IP services?
526
99:59:59,999 --> 99:59:59,999
So you can just spoof at will? And…
527
99:59:59,999 --> 99:59:59,999
can the birds see the physical
location of the source
528
99:59:59,999 --> 99:59:59,999
accurately enough to
find who is spoofing?
529
99:59:59,999 --> 99:59:59,999
Travis: I'm not an expert in Ku band. The…
for the downlink the bird has no clue
530
99:59:59,999 --> 99:59:59,999
as to the location of the dish. Because
you're only listening. They can roughly
531
99:59:59,999 --> 99:59:59,999
figure out your geographic area because…
they need to figure out where
532
99:59:59,999 --> 99:59:59,999
the spot beam is going. So they might know
whether you're in, say, Germany or
533
99:59:59,999 --> 99:59:59,999
in France. But they won't know whether
you're in Heidelberg or Mannheim.
534
99:59:59,999 --> 99:59:59,999
They do have forms of authentication for
many satellite networks. Satellite TV
535
99:59:59,999 --> 99:59:59,999
is one of the best-protected network
services because of the satellite wars
536
99:59:59,999 --> 99:59:59,999
in the 90's, in which TV pirates would
fight back and forth with smart card
537
99:59:59,999 --> 99:59:59,999
designers. But there are also many
unencrypted links. And there are…
538
99:59:59,999 --> 99:59:59,999
because of standard protocols those
are particularly easy to find in Ku band.
539
99:59:59,999 --> 99:59:59,999
Question: You've been talking about
using RTLSDR from osmocom.
540
99:59:59,999 --> 99:59:59,999
And you were talking about your spectrum
analysis program. Is this one working
541
99:59:59,999 --> 99:59:59,999
with RTLSDR?
542
99:59:59,999 --> 99:59:59,999
Travis: So… RTLSDR… so I'm using
the RTLSDR not the osmo-sdr.
543
99:59:59,999 --> 99:59:59,999
Which are separate. The spectrum
analyzer is working with the RTLSDR.
544
99:59:59,999 --> 99:59:59,999
My complaint about the RTLSDR is that
when you have a strong signal next to
545
99:59:59,999 --> 99:59:59,999
a weak signal the weak signal is
utterly useless for interpretation.
546
99:59:59,999 --> 99:59:59,999
Question: Okay. Thank you.
547
99:59:59,999 --> 99:59:59,999
Herald: Another question
from the internet?
548
99:59:59,999 --> 99:59:59,999
Signal Angel: Okay, next question from
the internet is: how do you record
549
99:59:59,999 --> 99:59:59,999
the radio signal from the dish,
at what sampling rate?
550
99:59:59,999 --> 99:59:59,999
Travis: The RTLSDR samples at 2 million
samples per second. As soon as I switch it
551
99:59:59,999 --> 99:59:59,999
over to the HackRF I'll be having
20 million samples per second.
552
99:59:59,999 --> 99:59:59,999
The sampling rate can be reduced once
the bandwidth of the signal is known.
553
99:59:59,999 --> 99:59:59,999
For reduced storage. And the recordings
can also be compressed.
554
99:59:59,999 --> 99:59:59,999
But it's still a hell of a lot of storage.
555
99:59:59,999 --> 99:59:59,999
Herald: Any other questions?
556
99:59:59,999 --> 99:59:59,999
Signal Angel: The internet
has more questions…
557
99:59:59,999 --> 99:59:59,999
Herald: Okay…
558
99:59:59,999 --> 99:59:59,999
Signal Angel: Did you look into obtaining
a capacity of IBAN with copper (?), as used
559
99:59:59,999 --> 99:59:59,999
for the rotary gentries in CT scanners?
Those can apparently transmit contactless
560
99:59:59,999 --> 99:59:59,999
several GBytes per
second, bi-directionally.
561
99:59:59,999 --> 99:59:59,999
Travis: I've not looked into those.
It seemed better to have an Umbellaco (?)
562
99:59:59,999 --> 99:59:59,999
cable and to be careful not to snap it.
563
99:59:59,999 --> 99:59:59,999
The whole thing was done for a budget
of less than 2000 Dollars, and can be
564
99:59:59,999 --> 99:59:59,999
recreated for less than a budget of 1000
[Dollars]. And they… so we tried to avoid
565
99:59:59,999 --> 99:59:59,999
fancy parts. The local radio shack loved
us because we'd swing in and buy all sorts
566
99:59:59,999 --> 99:59:59,999
of crazy stuff. As soon as we told them
that we wanted the satellite dish to
567
99:59:59,999 --> 99:59:59,999
dance Gangnam style…
laughs
568
99:59:59,999 --> 99:59:59,999
laughter
569
99:59:59,999 --> 99:59:59,999
in German, strong accent:
Danke, gerne!
570
99:59:59,999 --> 99:59:59,999
applause
571
99:59:59,999 --> 99:59:59,999
silent postroll titles
572
99:59:59,999 --> 99:59:59,999
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