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Well, good evening, everyone,
and welcome to this talk by
Andrew Writer
distributed RF Spectrum Analysis.
I think everyone's lately been buying
cheap SDR sticks and playing
with them and Andrew has
been doing more with them.
All right, thank you.
Like you said, my name is Andrew Ryder.
I come from us
and and I'm very happy and
glad that I was invited to be able to
come here and speak in front of all of
you. It's a pretty amazing place and
really amazing conference with a lot of
amazing, very friendly people
who are doing a lot more intense
work than I have. But hopefully this will
be very interesting to you all.
First off,
there is entirely too much content for us
to cover in one half hour session
here. You know, some of this
content, as you know, can be
given for a full length semester courses
at a university.
So like such as antenna theory,
things of that nature.
So don't worry about feeling confused.
Just sort of get
what I'm trying to get the key terms
that I'm throwing across, get
some of the ideas in your head
that I'm trying to express, and then
afterwards review the slides,
do some further searches on the Internet,
use the references, things of that
nature, and then hopefully,
you know, you can build your own array.
Lastly, a while ago, a friend
and I, we created this Radio Punk's
mailing list, sort of named after the
cyber punks, and
it hasn't gained much ground, but that's
really due to lack of trying to push it.
So there I'm pushing it.
The last slide or two has the link.
So as you all know, in recent
times, there's been a great deal of
increase in RF traffic.
We can particularly see this in the
United States because of the FCC
s working to reorganize
the frequency allocation table
and basically making
channels less
wide because of the accuracy of the
hardware and the increasing numbers
of people using the spectrum.
Also, the the cost reduction
in hardware has
now dropped a ton,
so there's a great deal more
devices being developed by manufacturers,
companies in that such.
And also there's people like Mike Ossman
and the people that made Blade RF that
are doing nonregulated
devices that can transmit.
So it's a challenge for us, in my
opinion, that we should
be wanting to know what is being
transmitted over the air.
And
so should what's in the air
also be in the air if it makes any
sense?
It's our duty to sort of first understand
channel frequency occupancy
and probability distributions
related to channels
in the spectrum and
how which protocols
are using them?
How often are devices
using those spaces in the spectrum,
things of that nature,
and so that we can be aware
sort of of the existence of signal
and then we can work towards
understanding the signals.
You know, the governments are listening
and so should we.
So I feel it's my duty
to sort of talk about the array that I've
built using our TELESTAR devices
so everybody else can build their own if
they desire, so that we
can, as a group, increase our knowledge
as to the existence of signals
throughout the spectrum and
then from there hopefully work towards
breaking them down.
So hopefully this will get you motivated
to build an array and then participate
in a future project that I'm working on,
which we sort of link everybody's arrays
together and get a feeling for the
worldwide RF spectrum since.
More of an innocent motivation for my
building, the array is effectively live
in the woods of western Massachusetts in
the hills, and so I go for hikes a lot
and two miles
into the woods or so I come across
this crazy device.
I'm like, what the heck?
It's got a
set antenna there.
And the
big guy right here,
the H.F. set,
and then also had a cellular
antenna.
And it was basically used for measuring
the water tables in the hill areas.
And so it really, you know,
made me kind of think, you know, oh,
wait, there are.
Places transmitting, even though I can't
see an antenna, and so I was like,
OK, you know what?
What is actually out there in the
spectrum around me?
I live in the woods. What can I capture?
What am I not seeing?
But first, before I go into some details,
I just want to be clear,
you are scanning array.
It's basically just a group of
of R.F.
receiving devices and their whole
purpose is discovering signals and RF
spectrum. This is just power analysis.
We're just, you know, 15
IQ data and
looking at the power values at different
frequencies.
And we're looking at
the noise floor over spikes
different from this is then,
you know, deep modulation and
analyzing the actual protocols that are
going over the spectrum and
identification of those protocols.
But as I've alluded just before,
recognition of the existence of a signal
is the first step to actually moving
forward.
The basic array components that you are
maybe all aware of or not,
you're going to need basically
five things software,
controllable, RF receiving capable
device.
This is something that will
do analog to digital conversion so you
can get IQ data.
What I'm going to show is that I use
stars, stars might be a misnomer
for these RTL devices as they
are more just controlled as opposed to
software defined radio.
Next, you'll obviously need antennas
in order to go out there and
reach out into the air and grab what's
there.
You'll need the cabling and adapters for
antenna and to the RF receivers.
Sometimes this is just sort of
overlooked. Not the cabling, obviously,
but just the fact that when you're
building out an array, you're going to
need a lot of cable, you're going to need
a lot of different adapters.
And it's sometimes a pain
in the butt because not everybody always
has them in stock, that kind of thing.
And then obviously a computer able to
control the RF receiving device
and then process any data that you get.
But this sort of naturally leads into
this sort of component choice problem.
And I just want to introduce
it early on because it's fairly
important.
Most receiving devices have a
fairly limited range
in terms of frequency, width,
bandwidth. For example,
if you look at
the Osman's hack
RF, you know, you're maxing out at 20
megs of bandwidth there, but
you're not even going to get that because
of the limitations on the USB bus.
And so you kind of need to be worried
about the device capabilities
that you're purchasing.
Further antennas also have sort of
frequency range issues
due to the nature of how RF is
transmitted and the spectrum.
You will have certain antennas
that are purposed for UHF,
for VHF, some work well for both.
Some are intended for a small
frequency range, but get high gain.
Some are intended for a wider frequency
range, but aren't that
receptive to the signals that are out
there.
Further, when you're getting
when you're building out this array,
you're also going to be acquiring a lot
of raw data.
And so if you're planning on storing it,
you better either have a lot of hard
drive space or just be ready to lose
the historical data.
So that's an option. You have the choice
you have to make. And further, well,
this choice is made for you.
Virtual machines are just really not an
option for this. This is just too
intense.
So there's a lot to consider here.
So the idea is that I suggest to start
small, start cheap, start with
the UCS and
start with VCF.
In the lower end of the spectrum,
basically, you know, use our
stars, that'll get you fifty megahertz,
the twenty two megahertz or
two point two gigahertz and
you know, you'll be able to get all the
cabling, the adapters
and all those things fairly cheap.
So I want to share with you sort of the
the receiving hardware that I've used,
as I mentioned, I've used the variety of
the real tech artle
20, eight, 30 to you based USB
sticks.
These most of the sticks that you find
will have this chip, but then you
have the tuner chip that goes along with
it. And the best tuner
chip out there for these
is basically Atlantics for thousands.
And
this will basically get you 50 megahertz
to two point two gigahertz with some gaps
at around 11 hundred to
thirteen hundred in that range.
I also have been using these Rafael,
micro tuners
and those aren't as good.
They get a little bit lower.
They get down to 30 megahertz or
something like that.
But there is a limitation.
I believe the upper band or the upper
bound is about 70 hundred megahertz.
So as you can see there
already, I'm kind of limited.
You know, I chose these.
I'm doing 50 to twenty two hundred or
thirty to seventeen
hundred.
Yeah, and
also in theory, these should support
a band with a three point to make,
but really if you're doing that, you're
going to actually have data loss.
And so it's basically recommended to drop
down. I know people have seen some
numbers, two point six, two point
four. I've basically just been doing my
setup with just two megahertz making
it power to.
And these are some of the devices that I
have actually mirror, the
ones on the outside are
the ones with the locks, tuners, and
they have power connectors.
The one in the middle here is a newer one
that I haven't used as much.
This is the one with the Rafaelle
tuner chip on it.
And the connector actually for the
antenna is an MSCs connector.
It's quite small, but it's a lot more
strong than
the power connector with the weight of
the cabling.
I frequently snap these off.
And the nice thing is, you know, I mean,
I don't know the scale is here, but it's
like, you know, the size of the end of my
pinkie. So soldering something like that
back on is quite easy compared to, you
know, a lot of the same, the stuff that's
going on today.
So that's really not a big deal.
So those are the actual
receiving units that I'm using
now, we go to some cabling
and adapters and that kind of thing for
basically everything. I'm using
cabling seventy five
ohm impotence.
And it's basically works great for
all the UHF and VHF analysis
that I'm doing currently,
the adapters that you're going to have to
be worrying about typically
for the.
For the poor guys on the
left and the right, you're going
to most likely need F type to pal.
And for
the guy in the middle here, typically
I put smart,
but really there's type to mix,
all sorts to mix.
I think I just made a typo
further. Another type of
adapter and plug that you don't need is
for typically for your antennas.
And
I wanted to point this out because
it's commonly used.
These are UHF plug, plug
or socket and the
actual plug right here and this is
a two fifty nine
plug that actually converts to
five.
But typically,
you know, when you're talking about F
type and semi and all those things, you
have female or male.
Well actually in this, this
realm you're actually talking about S02.
Thirty nine is
the female piece and
two fifty nine is the male piece.
This is like the weird, the weird
one in the in the whole bunch.
And as I said before, when
you have all of your hardware together
and you're like trying to assemble your
kit and you're missing one or two of
these adapters, it is a pain.
It is a real pain in the butt.
I've experienced it and I've had to wait
like a week or so because nobody
near me will sell any of this hardware.
And so I always have to order on eBay or
from specific for some specific
dealers down in the south of the
US, where apparently
there's a lot more people using ham
radios and things of that nature.
And the key is
to buy a bunch, always have extra,
always have a box of them, be able to
hand them out, friends, that kind of
thing.
And I also say to to look,
when you're looking if you use eBay to
order, beware of anybody
selling from China.
And I know that's kind of like a blanket
statement, but in all honesty, I've
had to wait three to four weeks at a time
just to clear customs, just to get an
adapter, which is just totally
ridiculous.
There's no harm in that.
Talk about intent is a little bit more
basically depending
on your needs location and
what where you're basing your array
really determines what antennas you
might want to get.
As I mentioned before, they're very
specific. And in terms of the frequency
ranges and the directionality
of them,
primarily, I use omnidirectional
discount antennas.
This is like the one on the left right
here.
The primary reason is because
of the omni directional nature of it.
I kind of live in the woods.
I don't really know exactly where
I'm looking for.
I know where there are some big towers
that are transmitting higher power, but
I don't know exactly what's going on all
the way around me.
And so I don't want to dedicate some
Yagi antenna or log periodic antenna
on the right here that are directional
so that I'm limiting my view.
My my one problem here
is that the omni directional, you know,
I'm losing some power.
I'm not getting all of the the
the power out of the the
the spectrum as I could, I guess.
Soucy
Furthermore, instead of buying an antenna
such as those, you can build one easily.
This is very easy to do.
You know, you just need some pine, some
screws, coathangers,
things of that nature.
And you can do this.
These guys I'm not going to show this
video now, but I wanted it in the slides.
The BBC, Ottawa folks
did a great little five minute video and
building a UHF, VHF,
HD TV receiver,
some of the first some of the new digital
over the air stuff.
And it's
like this big takes
five minutes to build that simple.
Furthermore, when you're
building out your antennas,
clearly mounting is a
is a big issue,
trees, buildings, they all block signals,
they can refract signals.
And so the idea is to get your antenna as
high as possible and with
clear lines of sight around as possible
if you're unable to do this.
One thing that I've been doing because
I rent the place that I live in
is that I've been taking
PVC and
basically building large amounts out of
them and then using other shelving
and basically building up and up its
total hack job. I'll show you pictures in
a few minutes, but it's it
works, you know, and so so
it's worth mentioning
further out of reference on the last
slide. And the references slide about
rules of thumb in terms of height
and distance to the transmitting tower
and sort of knowing what
you should get
out of a signal if you have an antenna,
certain height with a relatively clear
line of sight, those kinds of things.
And it's worth reading
the last two things, grounding
your antennas. This is important.
You're going to fry your electronics.
If you don't, I'm sure you will.
And probably the next most
important thing is labeling.
When you are building
out your array and you have
a bunch of antennas and then multiplexed
out to a bunch of wires,
you're going to need to know which wire
went to what antenna, if there ever was
an issue, you know, did the wind
knocked something down or whatever,
you're going to want to know which
machine that was going towards or
which antenna that was going to.
So it's sort of an example of just
using the omni directional head mount
and how easy it is to just put it onto a
PVC pipe.
It just fits quite nicely.
This is like a one and a quarter inch.
I know that's different here.
Sorry for the measurement changes
and it just fits on.
Right. Nice. And
boom those pictures and so great in this.
But you can see the sort of
wire shelf thing and then
these five foot antennas
that go up.
Admittedly, this is not the best setup.
Right.
I live on a big hill, though, and it's
sort of really does open up.
And so this actually works.
I get pretty clear, accurate signal.
And there isn't much interference
from those trees, mostly,
probably because they're thin fir trees
and that kind of thing like that.
And some of them are almost dead and
falling on the neighbor's house.
So that probably has something to do with
it as well.
Further, since I had this sort of way out
in the yard and the cables running down,
this is more of an up close picture.
You can see where I've done labeling.
It's very simple.
All I did was duct tape one
to duct tape three, duct tape, super
simple.
But what you see is that when you bring
the cabling back to the house at the
grounding site, which is also another
hack job, I
have, you know, labeling again
so that I know exactly
which cable came from way out in the yard
all the way directly to right where I'm
grounding.
And so at this point, you kind of have
your antennas out there and you're
wiring them into your house and
it's important to think about
your ability to maximize
the antenna usage.
What I mean by this is, you know, are
you going to be able to mount 10
antennas on your roof or
on your landlord's roof?
Probably not.
Or probably that's too much of a headache
or too costly to actually purchase those
antennas. Maybe you don't want to build
all of them, that kind of thing.
So really, what you're most likely going
to end up doing is buying a multiplex
here. And this basically takes an input
signal and splits it out
and output signals.
And typically, when you're thinking about
cost these multiplexes,
as you go up past the gigahertz
range, they're going to increase in cost
a great deal.
So that's something to consider when
you're trying to choose the the frequency
and the frequency
blocks that you're trying to scan and
monitor.
And further, with Multiplex's, it's
really worth knowing this trade off,
not amplified multiplexes,
will reduce the signal and typically
depends on the range
that the multiplex supports.
And when you buy it, it'll say right on
there and you just have to take that into
account when you're doing the power
analysis.
Also, you can just do amplified
multiplexes. So this is sort of an
example of one here
where there's a power in
and that actually goes to a 12 volt
adapter.
And it's it's it's good,
in my opinion. But the issue is that it's
a little bit noisy. You're basically just
adding game to the system and there's
added noise.
And so here sort of the mess.
And I even go further labeling
the multiplex level so that I know
exactly where in this whole chaotic
mess
antenna came in, where to go,
which node has the various
outputs, signals from that antenna.
And lastly, sort of just to give you a
picture, this is the 12
node or 12 story
that I have going now one,
two, three, four, four
four.
As you can see, most of them are the pal
type that I mentioned before,
and most of them are
sort of sagging downwards.
And yeah,
I guess there's nothing much
I can do with that. I've sort of put
some, like, little stents in there at
times, but it didn't really help very
much. Just those just continue to bend.
So this is kind of a
brief aside, don't buy
these
when I was first messing around and I
was just like, oh, I have one dongle,
I have to dongles, let's do the tetra
dongle and maybe an octave
dongle and these
just suck.
They will like I was just getting
spurious errors,
you know, they were partially in Libya,
USB some and Lipsy, but
it was totally the cables fault, I'm
sure of it.
So lastly, and
I know we're kind of getting time in,
the Greenwall talk is coming up,
there's a very important, very important
point to be made is that, well, now
that we have all this hardware here, we
need to be able to do something with it.
So we need to discuss the software side.
It's sort of my opinion that to do this
as a distributed approach, there's a lot
going on in the system.
And the positives of sort of spreading
this out include, you know, being able
to do the the
AIO on all the
different machines, be
able to do the CPU intensive
for year, transform
possibly on different machines, also the
data storage and just
doing all the rights for that.
That's helps to just push
that out.
However, the negatives are the fact that
you're going to have to buy extra
networking gear unless you just have some
around.
You have machine costs, the power.
If you don't have some extra machines
just laying around, then
that's you need to buy them.
And just in general, the complexity
increases any time you add systems to a
network.
Briefly, the designs, I quickly try
to sort of master slave setup using
the the pirate SDR
python bindings, driving the USB
dongles master slave set up
where each dongle associated with the
is associated with an TCP
process which is part of the
SDR Osmo.
Com guys, they push that out
and then using new radio on the master
to do a workflow.
And then lastly, this is the setup that
actually ended up using the most and
I have enjoyed using
the most.
And what I sort of recommend
or would hope people would work towards,
I guess, is that you have some
custom code that is heavily
based on the Osmakac.
Com guy stuff, fully admit that,
you know, all the licensing stuff goes to
them. That's great.
And and I will discuss
that. Now, we can
sort of skip this.
So with the first
example that I showed.
All of the the
sleeve notes which actually have the
SDR devices connected to
the antennas, well, then
recapture RF data
at a time. They'll capture some chunk of
sample size and then they'll just push
that IQ data back to the master.
They will just keep reading,
pushing, reading, pushing, reading,
pushing, reading, pushing the mass of the
whole time has to read off the wire,
do something with it.
And most of the time what it's doing is
50. So basically you're doing
50 per pack per capture
per slave on one machine
and then add the network.
I just go and that machine is basically,
you know, it's starting to eat the dust.
Similar kind of goes with this.
The second one that I mentioned just
before, which is where we have our TCP
running on all the different dongles on
all the different slave nodes.
It sort of matches this,
the topology on the right.
It's just using our TCP
instead of some pie
pie SDR
bindings that send over the IQ
data. This way it's low, it's
using the direct C-code, using
our TELESTAR directly
and sort of removes that overhead.
The different thing here that also by
using our TCP that I get
is the fact that I can then use the
radio companion and build my own
workflows and there's some real
flexibility in being able to do that.
The primary one that I was doing for the
power analysis was I was using the
to sources
past those into
these 50 blocks.
And then I wrote my own radio
sync that would aggregate the data and do
some just analysis, just comparing the
values and things that.
Furthermore, this also because
of the previous example, will
also crush your one machine because it's
doing a lot of the heavy lifting.
So sort of what I decided to come up with
is this monster diagram
in which actually reflects the
legitimate setup that I just showed
before, that I have running.
I have one M.A., I have a database,
three slaves.
And on each of the slaves there's four
artle dongles on them connected
to the antenna's via Multiplex's.
The design goal was to push all the 15
processes, all that 50 processing
back to the slaves and then just transmit
the power data back to the to the
to the database and stored in the
database and then let the master
query that database and find out
about what the nodes had found.
Another design goals to increase the
functionality away from just doing
just being able to do the 50 and
the power analysis to be able to say,
OK, I see a spike, let's roll
capture.
So, you know, I've
added that support to it also.
Similarly, if we see a spike
in some frequency
boom startup ARTlE TCP
and then choose a radio
script, maybe it's just fine and you can
just listen to it.
Maybe it's something else and you want to
do further decoding like box Zagor or
adsorb things of that nature.
So each live node
runs this thing that I call Megaman,
which is mega array monitor,
and as I said, it just captures the RF
data, does the 50 and inserts
powers in the database.
But once again, the database node
is there just to store
information about all the nodes,
physical location, longitude,
latitude, longitude, things of that
nature, actual device index on the
machine, its current status
as to whether it's
scanning or not.
Also, it stores the frequency block
distribution, how each of the
slaves choose which frequencies they're
scanning.
And all this is configured ahead of time.
I admit I'm running out of time.
So.
Let's see a couple of things here.
Primary things I have agree that I've
sort of developed
and
what this is showing here is
the power versus frequency
from 50 megahertz all the way to
nine hundred megahertz, which is pretty
cool considering that this is just a
little device is doing
to make some time.
That's pretty wide range.
And however,
note this bottom part here,
you can sort of see the three chunks.
Right, that
has to do with some cabling, some bad
antenna things of that nature, really,
that's just fixed.
See if I have a picture.
Yeah, here, I fixed that, essentially
using some manual game options and things
of that nature to level out the signals
and the purpose of that is
the purpose of my wanting to have that
a noise floor that's consistent
is the fact that I
have this thing that I call
a power brokers list.
I basically I can set a threshold value,
which is just the decimal value.
And and
you click refresh and it'll give me the
list of all the frequencies that broke
that threshold.
And it's very helpful. And just kind of
knowing over the last 10 minutes what's
been really spiking, what's been in
use and.
All right,
so further description
about my.
Like I said, it's scanning 50 to 50
megahertz, nine hundred megahertz for
stars per node,
12 times to Muggeridge
and then three omnidirectional
UHF VHF discount antennas,
three, four way amplified multiple
lectures. I've had this running seven
days at a time.
Only reason to take it down is to update
code things of that nature.
No memory leaks.
It just runs. It just goes.
And it sucks power out of my house.
But it's fun.
Again, I, I apologize,
but I'm going to have to urge you to kind
of go back and look at some of these
slides to just sort of realize
how I do the breakdowns in the range, how
I associate them to each of the device
nodes and how they scan
further. I also have some
example videos that are a bit
too long right at this point in time for
me to share that sort of
describe, although
I thought this was kind of neat.
Your presentation.
Yes.
Yes, so this I
found like.
Yes, ask the question, I think I
know the story now.
Yes, yes.
I mean, I think a lot of
a lot of them, they want to have
to name but another woman.
They.
The room is available for the next
half hour or something still, so,
um, he's asking
if there's still
time here to finish
at the beginning where we would
like to see more than a
sure thing here.
I think people will leave now, you know.
Is that OK with you guys?
Uh, yeah, we are.
OK, let's just continue for recess
for a moment and let those sleep for
one week.
Thanks.
I'm sure the green one is good in.
A couple of moments, we're still sorting
video again.
We're back.
I appreciate that you guys are all
interested guys is a bad term,
I apologize.
I know there's a lot of uproar about
that.
So to skip back to where
I was discussing I was just mentioning
the different notes that I have.
I mentioned the slip notes to death,
the database note there's not
too much exciting here.
Just know that this is there's a couple
of key things.
There's configuration
in the frequency block distribution and
the note information so that we actually
know which machines have what nodes
and then assigning frequencies to those
nodes.
This is a
step that's a little bit weird to be
doing command control
by.
Or command dissemination by a database
table, but I already
had the database up and running, so I'll
just like let me just make a command
stable and then just insert it to it and
then they can query it and they get a
command boom. They can continue going.
Basically, the commands are there for
just starting the scan,
stopping the scan, starting the
stream, stopping that
doing right.
Rikyu rights
to the file, that kind of thing.
So it just gives you a little bit more
flexibility than other other than just
receiving these power values
and being able to do analysis on that.
So this master node, as I said, it just
sort of its whole thing is to control
the slave nodes via
the DB and
all this is kind of a little bit
repetitive.
But the only direct
interaction with the slave nodes that it
will ever have is if you optionally
decide to say, hey, I want to
do our TCP and
run a flow graph, well, then obviously
your master node is then physically
connecting to that TCP port on that slave
node machine. And so then
boom, you're connected with it.
Also, the way I do the raw
file captures as I want to aggregate them
from various nodes.
And so really what I do is I just have
nafs mounts that mount
onto the slave nodes.
I write locally the IQ
data to a file on disk,
but then I move it over to the NAFS mount
after the capture is done, all that kind
of jazz.
So those are the kind of two real
direct interactions between the
master and the slaves.
Everything else is done via the database,
which I don't I still don't know how I
feel about that. I'm so used to just
having
protocols embedded or commands
embedded in a protocol somehow.
But this is just another form of protocol
anyway. So the Master
GUI that I've kind of developed has the
power over spectrograph this
plot frequency on the x axis,
power on the Y axis,
and is a dynamically configured view
range. You can basically set min max.
So if you want to hone in just on
the FM band and look at
eighty five FM to, to
110 FM or something like that, you can
get just that chunk and see it in
much more detail.
Also that you'll see
is a power over time graph based.
The thing is you choose a specific
frequency and it'll give you the, the,
the power levels over recent time.
This is sort of useful to see.
Wait, was that just some spurious, like
Spike that who knows what the heck that
was? Or is this a commonly used
frequency by people which usually
over time you can sort of tell
and obviously both refreshed with time.
And then lastly, is this a power threshed
breaker's?
Which sort of strong signal analysis
might be a strong phrase for it?
But the idea is here, just as I meant, as
you'll see, just give you a list of
of of frequencies that
are showing strong signals
and the ability to kind of
double click on them and then have it
automatically pop up in the power
and the power versus time graph
or just double click it and
then say run.
It'll automatically hook up
to an TCP
or a node running our TCP and then do the
RFMD modulation.
And so it kind of just the whole idea of
this GUI is to make the
flexibility that I'm aiming
for in this array to
actually be user friendly, which
hopefully is probably going to be a more
long term goal than anything.
So I briefly mentioned this,
but I want to put up the slide again.
So that it's clear what I have here is
essentially a four machines, three
slave nodes, one master,
and then I share the master with the
DB scanning
50 to 900 megahertz cetera, et
cetera.
All the known hardware is pretty much
things I found around my house.
My master is just a 64
bit laptop with
gig around and it's
fine. I have an external hard drive
over USB 2.0
and it works fine.
The slaves are a mixture of 32 bit and 64
bit machines. No, no more than two gig
of RAM and each.
And really the processes never gets
over like
20.
I have to verify that by like 20 2k
or something like that. It's really small
and they're all running Linux and the
like. I just said, the idea is to just
use the machines that you have laying
around your house, I'm sure.
And all of us have either, you know,
machines that we've gone through and
they're just, you know, junk now
and well, they can be repurposed for this
type of work.
So sort of repetitive break
these 50 to nine or down into
three chunks, these
three chunks are assigned to each of the
antennas that I have, and then
I break each of those three chunks
down into four sub blocks that
are assigned to each of the nodes,
RTL, sorry, each
of the dongles.
So it sort of looks like this.
You have the full block and then you
break it into three based upon the
antenna.
And then, you know, you
break a small chunk of that one and
index zero, one, two, three.
So I kind of do a uniform
breakup of the spectrum to the resources
I have available.
So if you're going to have to excuse
sort of the video
in some senses, because I
was trying to do this with a cell phone
and like type at the same time.
Some cuts here to Sean.
So let me start that from beginning to.
So I see.
So I'm just sorting the frequencies that
are broken into this DV threshold.
I see that I grabbed ninety two point two
megahertz just about
to jump in,
but I want to actually then listen to it.
So what I did is I go to this menu that I
have and I was able to say no to zero
one dash three, stop
scanning, but then start started TCP.
Obviously this is stuff you want to
automate, but it's all for
that now.
OK.
No. Zero one three is
now streaming.
So pops up in my little list.
Double click, double click.
It already remembers the fact that we had
double click the frequency before.
And then just once the radio
being and
I thought this is kind of neat because
this was totally random.
A friend of.
You know,
I thought that was kind of neat because
it was totally random, I was just trying
to film something for this.
I was like, oh, I'm going to
see this might give a little bit better
the demo, but
so here you can see some of the frequency
that some of the interface.
I have a last minute thing here now so
that I can sort
of say, hey, you know, I want to expand
the
Breakers list in time.
So let's see.
Choose 157 randomly
and I see the power analysis versus time.
Sorry.
Focus elsewhere.
Here we go.
So you can see it's a pretty strong study
signal, a couple of drops here and there.
So I decided you
have found Imada. That's.
Right.
So.
The idea of those two videos was just to
give I know they were not very pretty,
but just to give an idea as to
sort of the flexibility that I'm going
for, the ability to see
the spectrum and then
pick out certain parts of the spectrum,
look at it over time, and then possibly
doing some real time analysis or possibly
capturing that data to a final doing
post-processing.
So there's still some work to be done
to make that all very clean.
But the the basic
building blocks are there and you just
need to link up a few methods.
So let's so let's listen
to one
thing on performance, which
I think I skipped the end of that last
video, which actually might be
interesting to show.
I didn't include it.
The point was, is that you will see
on the power on the power graph, the
spectrum graph, that
one of the notes will be taken out of the
light, taken out of use when it's
actually being used for
streaming. And so there's actually like
that chunk that has no
signals recently available to it.
So it's like you have all this signal, a
signal like noise for signal and ball,
but then it just drops off and
then picks back up.
And that's a weakness.
Something that could be done is
reconfiguring surrounding
nodes to try to pick up the slack,
some very wimpy statistics
that have kind of generated.
OK,
is
basically this is just doing sort of a
select queries on on the database just
to see in general what I've gotten, and
it's basically one power sample per
frequency every three seconds.
And then the database
with insertion of this frequency values
over the entire fifty to nine hundred
megahertz spectrum. I'm increasing one
gig at a time or a day or
one gig per hour.
And these are just sort of rough
statistics. And there's definitely more
that should be done in terms of analyzing
how one uses TCP
or writing out to a file and how
that impacts the
number of samples put in
per second, that kind of thing.
My next steps for this array, and I know
I'm wrapping it up here,
is basically, like I mentioned, a work in
progress in the GUI.
There's a few things that I just want to
clean up and then hook some of these
other manual pieces together so that
instead of me clicking to stop
the from scanning, starting
the TCP stream clicking
that I want the firm just
do it, you know, that should all just be
hidden.
It's capable, it's just a method calls
and is all there.
And if you
do want the code to
come talk to me, I will, I will give it
out. But admittedly, there's some things
I'd like to update before I release it.
My plan is to release this so
that people can take it and modify it,
enhance it and make it better.
I'm sure they can do that.
Additionally to the array, I'm planning
to add two more
antennas and these are
log periodic antennas
that I sort of actually building
together. This you can buy for like
thirty bucks on eBay or from
a lot of retailers, and this
thing can work fine on its own.
And you sort of point it in the direction
that you want to go
and it'll do nine hundred megahertz to
twenty or two point six gigahertz.
So you can clearly see here.
But the idea is to maximize its
use as you want to build a corner
reflector. This is a total hacked up
version and there's a lot more work to be
done. But it basically what you do
is you point it, you have a nine,
you have 90 degree angle here
and you point to.
Into the air and you have a boom that
comes out and the idea is that signals
get reflected from both sides and hit
it and increase
the actual gain on that
antenna.
Now, lastly, the thing that I really
wanted to mention is
this next bigger project.
And this is the last thing.
One of my goals is that
since all these devices are so cheap
now, I really want to have everybody
be able to build their own
receiving arrays, sort of like around the
world, and then somehow link them all up
in some sort of like worldwide RF sense
network.
And so that I
I mean, it's more locally you'll see
propagation of signals and stuff like
that. But it would be interesting to see
what the global picture looks like over
the whole spectrum.
So please email me at Azara
Watson if you want that source or to help
out with this at all.
And again, I will be releasing the source
soon. So thank you
to these people.
And remember the Radio Punk's list.
Oh, sorry.
This is a little bit rushed and
I'm glad that you guys all got to stay.
And sorry if you missed.
Thank you, Mayor.
Well, thanks for being with us and
question the rest.
Yes.
You got to keep that in mind.
Yeah, that's a good
so there are things that are not
discussed in here basically to shorten
the talk, which is
thank you.
The question was basically I mentioned
earlier about watching the watchers and
that political statement and with the
hardware devices that I have now, can I
really do what I want to do, you know,
say doing 50 megahertz to twenty two
hundred megahertz, that kind of thing.
Now, you're right.
You have very good points there.
One thing that I did not mention is the
use of,
you know, up converters and down
converters and things of that nature in
order to say, you know, do in the
band and all that kind of stuff or down
and low in the ham bands.
So that would
be better. But again, you're just adding
more hardware and more devices and you're
going to get more cabling and things like
that.
There's a case to be argued is
should should one be using us, RP's
instead of this?
Well, there like a minimum 700,
800 bucks.
I don't I don't have that.
And then I don't have, like, a Giggie
network at home, you know,
to to run that.
And so
while this may be a bit of a hacked
situation, it kind
of works. And
for the moment, yeah, it's a start.
And maybe there's things
to do. Maybe instead of buying
for dongles, you buy
one USB thing that
does Effie's on the
on the USB stick itself, that
kind of thing, and and just sort of
change it so that there's more specific
hardware that's still relatively cheap.
Is there any other questions?
Yes, and do you
think one of those low powered
arm, like, could be bought
or acidify would be sufficient to run
the slave out here? Could you repeat your
question, please? This he was asking
whether or not like, say, Raspberry
Pi or or some other
small form factor, low power
device would be able to power one of
these. And that's a good question.
I don't know very much about how well
Mufti's work on our PI
and that kind of thing.
My guess is that it would work.
I know people have done
spectrum analysis using phones
and just the dongle
attached that way.
So and I actually now that I'm really
thinking about it, I have heard of
projects using our by doing spectral
analysis with our TLT stars.
So that would work.
And this sort of
another thing that I was unable to touch
on was I did some work in terms of
placing with friends
laptops throughout the town that
I live in and basically
using the public Wi-Fi.
And what I would do is I open the port
up on my router and basically
did
scanning from those places throughout
the town, you know, logged their
latitude, longitude and then use the
public Wi-Fi to send the data back
home.
And so part of my thinking
was, is that if one had the money
or I'm sure people maybe
do or just have enough hardware to do
this is
you could just take one of those are with
a battery pack or maybe some sort of
solar thing, throw it in a bush,
throw it on like a roof, and
then have it talking over the public
Wi-Fi. Back to you.
And you're getting data from all around
the town and that way.
And that's sort of my real desire.
But the costs on that are
a little bit prohibitive for me.
The problem of the
OK, if you have a question, please
stand next to a mic,
otherwise the people in the street won't
get it.
I can I can address the
floating point, like the 50s on
unarm a little bit
because I've been using our Rimbaud's
for some robotics and
they work fine if you're going to do it,
like if your nephew is going to be sort
of like a batch process where you're
listening and you gathering data and
then you would process it later.
They're not the performance on ARM
right now for floating point comparison
to Intel.
Still really not that good.
Where it kind of falls down is
if you're trying to do something like
real time sensor integration, like
through a common filter,
you big-boned black can do
that. But like
you would want to have one
board dedicated just
to that, just to doing your
fees or just to doing your other floating
point operations.
OK, I have a robot at home
where I'm using a beagle bone
to process data off of
a off of a light off of a white wider
and just
the amount of which is
spinning around like 60 times
a second.
So that's enough
to keep one beagle bone busy.
And then the common filter
to integrate the Odama tree, along with
the data coming off the IMU
to to do the sensor fusion
pretty much requires another separate
unit. Is it so we're talking boards
that I know these are just separate
individual units.
They're hooked up together over a small
Ethernet switch.
Um, their say
in communicating over X-Mailer
PC published subscribe
protocol.
But the the I had
had it I had had a separate
board just to do
see the CF transformers because
it just that kind of floating point just,
just crushes a little board like
that. And I have a feeling that a
Raspberry Pi would be less
so I guess. Well I guess what I'm trying
to say is if you want to do this batch
thing like you go to sleep and you let it
run overnight or something like that, I'd
probably be, gosh, OK, it's
just not going to be good for real time.
Gotcha.
I see people leaving.
We're running kind of late.
So if you have more questions,
please talk to the speaker
afterwards.
Thank you.