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- MCP server with stdio transport for local use
- Search episodes, transcripts, hosts, and series
- 4,511 episodes with metadata and transcripts
- Data loader with in-memory JSON storage

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Episode: 571
Title: HPR0571: Hack Radio Live 9
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr0571/hpr0571.mp3
Transcribed: 2025-10-07 23:20:34
---
This train is sort of inbound.
Some frame from sectors.
My crime is that of outsmarting you.
If you have not yet submitted your identity to the Retinal Clearance System.
Communications interface online.
You're not dealing with AT&T.
Automatic medical systems engaged.
Welcome to the Internet, my friend.
How can I help you?
Defensive weapon selection system activated.
Has been very safe day.
From San Diego, California.
I'm Drake Anubis.
Yeah.
Okay, so we don't have anigma this week.
I know.
I know.
But he is off presumably making the world a better place.
But joining us, we're lucky to have all the way from London.
Belial of the Hackers voice fame.
Fantastically popular UK podcast.
He's a scholar, polymath, renaissance man.
Good guy.
I don't know.
Belial, how was your Sunday?
It was good.
I spent most of the day driving around looking at places to get married.
That was quite interesting.
We were looking at some to stately homes and venues for hosting the reception.
Obviously the main event itself.
That was the main day.
I was taking up doing that.
That sounds fun.
My Sunday hasn't started yet because of time.
I'll let you know how close after the fact.
Yeah, it's quite strange that obviously your day is just beginning and my day is winding up to a close.
So I'm going to have dinner after this and you're just having breakfast.
So that's quite busy.
Yeah, that's how the world works.
What kind of fun did you bring today?
Well, I'd like to have a chat about some stuff that I used to work on when I was younger.
And I had a kind of interested in radio frequency to various degrees of actual radio telecommunications to radar.
And maybe some of the listeners will be interested in finding out that it's not actually that expensive or mainly out of reach of people to be able to create their own radar and object detection systems with maybe things that they might have.
In their own home, possibly.
It's not too expensive to be able to hook up a homebrew kind of radar detection, maybe detect your own car or some other metallic objects.
Things you might have in your home like a bottle and some string and such or what are we talking about?
Yeah, not so much.
An oscilloscope, a can would work.
What you really need is it's two very simple devices.
One is your signal generator, which you can use as maybe a signal generator itself like an oscilloscope type device with an RF antenna, which has to be the right kind of length for the wavelength that you're trying to generate.
And you can use you can make it yourself by going to some sort of shop that sells electronic kits.
I don't know what you guys have over there in the States.
We have not much. We used to have radio track and they turned into a cell phone and RC car store and we.
Okay, someone have fries electronics on the west coast, but that's about it.
Okay, so I guess you could use a some sort of RC radio control device, something that something that will generate a frequency of radio electromagnetic pulse as it were.
What frequency are we talking about? Like 20 megahertz like 20 gigahertz or?
Well, it doesn't matter really.
Yeah, I mean, the radio wave band is really quite wide.
You said 20 gigahertz and you're not far off.
You could use 20 60 gigahertz, 50 gigahertz or the kind of ultra military sensitive devices from 40 to 60 is kind of the Q band, which is the military.
Nothing that high though. Yeah, well, you probably wouldn't, but but something within VHF range would be would be acceptable.
So 30 to 330 megahertz, which is 0.9 to 6 meter wavelength.
So HF, you could probably do three to 30 megahertz, which will probably be in the band of your remote control helicopter type things.
You're maybe your if you have like a remote control garage door.
Well, you know what I do have is I have a bunch of CB radio equipment. That's all in the 27 megahertz range.
Okay. Yeah, that's perfect.
And if you can generate a 10 to maybe 100 meter wavelength, that's kind of over the horizon radar.
That's very, very long range radar. That's perfect for that. I mean, probably for a home brew kind of kit.
It's probably too big to be detecting those kind of waves. But what you could do is you could you could not so much concentrate on generating, but also receiving it.
So maybe you could do a passive radar and actually detect planes as they fly overhead by just having a an antenna array.
So instead of looking at it as generating and receiving the signal, you're only just receiving the signal. So that could work.
Like receiving the signal from someone else's radar, like bouncing down. Yeah, exactly.
Yes. And and and you could you could use your home.
Ham radio equipment, maybe with an oscilloscope as well for management measuring.
You'd have to calibrate your equipment to a certain extent so that you you're aware of the signal distance and strength.
And based on that, you can find out where the pointers and the signal that's drawn on the oscilloscope and convert that into meters of distance or kilometers or miles or whatever your measurement band is.
How many watts of transmitting power would you need to be effective?
Well, it depends how far you want to transmit. There is a nice little equation that you can use to actually to actually draw the curve of transmitting power over gain and effective aperture or area that covers your your field of view.
We're talking about short distance radar. So let's say your your garden, not very much.
You could probably do like a 1.5 watt transmission. And if you I mean you could have like a source like a like a pan or something and you could transmit a directional pulse of of maybe 27 megahertz or 30 megahertz.
And and kind of if you had to some sort of like a window wiper motor and just have it going from left to right.
And if you had that going from left to right at certain speed, you could then with a fixed antenna, it pick up the signal of when it bounces off that off that fixed plane, which is what you're detecting as a, I don't know, an aircraft or some sort of
stealth bomber or something, whatever you think that it could be. And then moving it forward, you'll see that the signal strength of that as every time that high frequency sweep passes across it, it will scatter that and some of that will deflect back onto your receiving antenna.
And that's where you'll get your blip on your oscilloscope. So as that blip increases in intensity, that will measure up to a distance of each time the intensity increases.
The distance will become shorter and shorter because the actual object is is closer and closer to you.
So that's that's quite interesting. But I mean, all this kind of stuff. I don't know how much budget you need. Obviously, if you don't have it already, then you're going to have to buy stuff.
But if you're already into the kind of radio stuff and you have ham radio equipment, the stuff that you already have, you can actually start doing basic radar.
Well, you know, an oscilloscope is really handy to have. So if you don't have one, I actually don't have a good one. I need to actually buy a nice one, but you can get cheap oscilloscope cheap and likely, but at like $100 to $200, which is like what a thousand pounds.
Actually, no, it'd be the other way because a hundred pounds is like a billion dollars now.
Yes, probably. But you don't need an oscilloscope so much as if you have a laptop, you can turn a laptop into an oscilloscope.
Oh, tell me how. Yeah. So there's there's if you Google for
an oscilloscope type applications, you can download from the internet for free and for charge as well.
You can use the line in input of your really a sound card and actually use those signals that you get transmitted such as audio, whatever is the same kind of thing.
That's all you're measuring is is a voltage rate of other of a signal coming into the input and using that, you can actually turn your laptop into an oscilloscope.
It might it won't be as obviously it's not going to be on the same scale of accuracy and you don't want to depend on it for any kind of actual purpose of measuring.
Yeah, for your actual radar system. Yeah, for your actual area.
But if you had a, I mean, if you were really, really going to go for all out and actually buy an oscilloscope,
but you could use the comport of your laptop and have some sort of breakout board to measure different voltages and use either custom or purchase the software.
You can you can do quite a lot of stuff without.
I've seen USB oscilloscopes. I don't know how good they are. I've always kind of wondered.
Yeah, yeah, exactly. We're like a USB oscilloscope. You can buy off eBay.
I don't think that they're for like the home market. They're probably perfect because you don't need that much varied calibration and accuracy on it.
But just to be able to measure some inputs and and draw him on the next Y kind of scope, then that's that's perfect.
You can apply that to lots of home-born projects that you can do.
I hope to send you a picture after the show. I probably put a link in the show notes.
But I have an oscilloscope here that is probably from the days where the British actually first created radar because I think it's actually like a 1930s oscilloscope like it has vacuum tubes and things.
Yeah, it's incredible. It probably won't be up to the task because it doesn't actually turn on, I don't think.
But it's just so awesome.
I don't think people understand how immensely heavy those things used to be because when I was in school, we had the huge oscilloscopes with maybe only four or five different inputs.
They were quite that this play was wasn't that big. It was maybe 20 centimeters by, I don't know, 40 centimeters high, but it was deep.
So it would it would be really, really long and so heavy and it would have a it would have a handle on the top to carry it.
But you know, you could only carry it for maybe short distances before you're on.
That's this one. You just described this one.
Yeah, probably.
It has an actual metal case only has like three inputs and actually physical dials in the front and such.
Yeah, so yeah, that's the ones that we we used when I was at school.
And the screen surround vacuum tube.
Yeah, yeah, yeah, that's the one here.
It's sort of like a green mesh in the front so that it catches the electrodes and they actually like stuff up.
But I mean, you can turn those things into displays like a actual not an LCD display, obviously, but you could turn them into a computer display.
Like an easy visualizer or something.
Yeah, yeah, exactly. You can you can display text on them if you were clever enough to actually output the right X Y and the right speed to rotate through the through the different blips.
You can get some sort of a really geeky version of those things.
You see it the overpriced gadget stores with a whip's back and forth and uses persistence of vision to create display.
Yeah, exactly. Yeah, except it's probably going to be a little bit better because the.
I guess that the accuracy of the displays is good so you can actually get quite quite decent resolution out of those things.
Really?
Well, I mean, the first ever computer game was was made by using an oscilloscope as a display, an actual game display where it refreshed a pong grid.
So you had two little paddles on either side and a little ball that went across and two inputs of the Y, I guess, range.
Oh, yeah, I didn't know this.
Oh, yeah, yeah, yeah, just, yeah, Google for it.
I'm surprised it's not like tic-tac-toe or something more trivial. I guess it will be kind of harder than that.
Yeah, first pong game and there we go.
Tennis for two. Yeah, the original pong game.
But it's not actually pong. It's sort of just like tennis.
I'm just pasting that link into.
Oh, let me take one of that.
Tennis for two. Yeah.
Oh, wow, it's actually going on a oscilloscope.
Yeah, yeah, it's a genuine oscilloscope playing a computer game.
Oh, there's an old controller or just not a controller at all, really.
That's like a project box with a button and a knob.
Yeah, well, yeah, that's what they were. I mean, it's quite simple stuff.
Oh, it looks cool though. Yeah.
Oh, it's gone in the show notes.
So there's lots of applications you can use oscilloscope for.
They're really quite versatile things.
But one of the coolest things that I've seen and I've not really done myself,
but I've read about it is actually lightning radar.
It's long distance lightning strike detection, which is,
it sounds really, really cool, but it's also extremely fun to do.
As a project, because it teaches you a lot about antennas
and a lot about high frequency and radio frequency detection,
because all radio frequency is, it's basically a current going through a bit of metal
and generating electromagnetic pulse.
And something else on the other end, being able to detect that wave
and it's similar to sound waves propagating through air
except electromagnetic waves are much, much faster.
And they have varied frequencies and also modulations
as they travel across through barriers like walls and planes
and all sorts of things.
They can break through barriers unlike sound waves.
So Sonar is really good for radar underwater,
because it can be conducted through water much easier.
So does lightning create like an electromagnetic signature when it strikes?
Yeah, that's exactly it.
Yeah, so the actual lightning acts as a really powerful radio antenna generator.
So it generates a 10 kilohertz range pulse
which sort of expands across throughout the world.
So it kind of will bounce across the ionosphere
and you can detect it many, many, many miles away
from where you are at that point in time
to actually be able to detect lightning
with any degree of accuracy you need to
of these points anywhere in the world
to actually generate lightning strikes.
So if you have a friend who might be across from the United States of you
so maybe a few kilometers further away from me.
So you couldn't have like two on opposite sides of your house?
Not with any degree of accuracy.
No, it needs at least like 50 kilometers distance between yourself.
That's not unreasonable.
Yeah, the reason why is that what you're trying to detect
could be 200, 300 kilometers away from you.
So the two points of the triangle need to be fairly distant apart
for you to get the accuracy of the actual third point.
Sure.
And you can do all this from a sound card
and a bit of home brew wire gauge and wood
to actually make you antenna.
You have two loops so for your western east orientation
and you basically hook them up through a quite clever antenna connector
which you can just use an Ethernet RJ45 Terminator
and plug a UDP cable straight into that
and then using the coils for your west and east.
So just two loops to terminate them across to your RJ45 UDP cable
back to another Terminator to a 35 mil jack
which I'm going to your laptop and using a bit of software
which is called the actual lightning radar if you're Google for that.
I'll send you a link to this page so that your listeners can look it up after the show.
You can actually analyze the coil data that comes through
to a varying degree of accuracy actually through the software.
So depending on where you are or your actual orientation in the world
this is taken from a viewpoint of the UK.
You can actually with some level of degree of accuracy
draw a 180 degree radar scope and detect lightning as it hits around you.
So it's pretty cool.
And if you have more than one of these detection stations
you can get some really good accuracy on that and detect stuff.
So you could have like four or five?
Yeah, you could have as many as you want.
There isn't really a limit.
Is there a community around this like online of people who connect the stations together?
I guess so. I don't think it's that big.
I think in the Netherlands this is where this project originated from.
There's probably a few guys that do it together.
I don't know. I don't think it's something as big as freaking would be
but it's probably just like guys from the universities that kind of do it together.
I'll send you that link now.
It's quite a niche thing to be doing and detecting lightning.
It's not kind of the most common thing that people think of when they think about radar.
Let me see. Oh, this is cool.
Oh, it showed you a map.
Okay, so are each one of those yellow dots a lightning strike or just a...
Yeah, exactly. Yeah, they're lightning hits.
That's all lightning.
Yeah, that's all lightning here.
And what people don't understand is maybe not understand but maybe can't grasp
as that lightning goes on all the time.
It's constantly striking the earth all the time somewhere in the world.
Just because it's not raining where you are, you could be raining maybe 60 kilometers away from you
and that's where lightning's happening.
You have no idea that that's happening but with the lightning radar you can actually pick that up
and have an idea of what's happening.
I guess if you really wanted to get really quite technical about it,
you could have your own weather station detection system and see what the front's moving
from west to east or east to west as the winds kind of sweep the lightning across.
Oh, they have antenna diagrams and connector diagrams.
Oh, this is fantastic.
Yeah, yeah.
So everything there is set up for you to be able to build your own two-wheel antenna.
I love these applications screenshots because they look like science
because they have all the graphs on the side and everything.
Impress your friends with your lightning detector.
Yeah, exactly.
You could.
Yeah, if your friends were impressed by this kind of stuff, I don't know if they wouldn't be.
Have you tried doing this?
I don't know.
No, not the radar.
Not the lightning radar.
It's something that I thought was really, really cool.
A very cool application to be able to detect lightning strikes
because it's kind of, I've always known about the fact that lightning obviously creates
high-frequency electromagnetic waves because of the simple fact that it's just a huge amount of energy
being dispersed into the atmosphere.
It's got to, you know, you can hear it.
Yeah.
The thunder is, you can see it first of all and then you hear it.
And yeah, it does actually, you know, disperse a click through the air sort of thing
as it kind of strikes.
But it's not something I've ever thought about detecting.
It's not the area of radar detection that I've done is in the kind of 30 megahertz to 400 megahertz range.
And it's more of kind of imaging like cars and stuff as they pass rather than actual lightning strikes.
Oh, yeah.
So you've had your own radar system before?
Yeah.
I've set my own little radar system sort of detecting cars as they pass through walls.
Oh, really?
So you had it on one side of a wall and you could watch and pass on the street?
Yeah, exactly.
And if you have it so that it sweeps from left to right, maybe like a 45 degree angle,
you can basically sweep across a whole side street and just see these blips moving.
And if you go up the frequency range, so going into the gear hertz range,
you're actually increasing the resolution of your radar sweep so you can get a little bit more detail.
And I know you guys in the States have those kind of see through scanners when you go past your airport security.
Oh, the millimeter wave technology.
Yeah.
Yeah, exactly.
That's kind of that's kind of works on that same principle where it's such a high frequency radio wave that hits your body.
And as it scatters or back scatters, it draws a picture on to the receiver.
And that's where the high resolution imagery comes back.
And that's kind of the similar principle of objectives.
They what they tend to do is they fly through the air.
If they're on their own or if they're on a team is the radar system will actually it's not like a continuous feed of live data of the sky.
It's patches of the sky being fed through the computer.
So it will basically it's difficult to explain without kind of showing you a picture that it kind of sweeps from left to right across the horizon and taking the snaps of select pictures of areas of the sky.
Sort of like in a pirat panorama.
So if you only had a certain frame that you could take you couldn't take a whole panorama it would take chunks of the sky out.
And then it will zigzag across the left hand side of the horizon and then back across to the right and then zigzag across to the top left and then to the right and then back down to the bottom left and then to the right bottom.
And then it would basically draw a radar map to the fighter pilot of what's happening in the horizon.
And the fighter pilot would based on the most priority target which would be right in front of you maybe to your side and below you would pick out those areas where are most important.
And that's where the radar would most mostly focus on where it's doing its banning.
So yeah and if you have two planes they will actually crisscross across their maps and one will draw the middle and the other one draw with the sides and fill in the whole horizon.
So they can actually communicate to each other.
Oh that's cool, that's really efficient.
I'm trying to think of what I could use for my radar and the only thing I think of that has anything really high would be the microwave in terms of frequency with that can't be advisable to use as a signal generator.
No that's perfectly fine.
My microwaves are obviously if you take your microwave generator out of your microwave oven that's probably not so advisable because of the wattage that it uses.
So an average microwave is what 750 to 850 watts enough to cook it up.
Yeah it's enough to cook your meal which is exactly what it's designed to do.
It's supposed to energize those water molecules inside your chicken or whatever you're having and heat that up.
Now that specific application is probably not ideal for radar because you don't want to destroy the target that you're trying to image.
Not necessarily I guess you could you could have some sort of death ray but that's probably not you know it's you're supposed to be passing so the target isn't really supposed to know that it's being scanned.
So but yes I mean rate microwave radar is probably the most accurate and high resolution radar you can have but the energy in the actual waves are a lot less than a microwave oven.
So you're talking about maybe 1.5 watts if even that where the precision comes from is not so much from the radio wave generation but in the actual modulation of the radio waves and also the receiving antenna array.
So what happens with high frequency radar is that the actual radio waves are modulated to a time slot so that each wave has its own time allocation kind of in the actual frequency modulation signal as the wave is generated.
The receiver antenna knows that what it's getting back is 30 seconds ago of what was generated and based on that you can have a quicker understanding of what's happening in the sky because it will take slices out of the horizon at maybe 10 degrees each side.
So 10 degrees 10 degrees 10 degrees all the way through to the right hand side of the horizon or maybe a complete 360 degrees in 10 degrees slots and break those down each one is a time modulated sample of the sky and the receiver antenna will will basically put all those samples back together and give you a map of what's happening so that's kind of how that works.
So rare only detects largely metallic optics, right?
Yeah, things that will disperse the radio waves so metallic objects are perfect for that application which is why planes which is why radar is used for detecting planes I guess and cars and anything that is quite quite a large metallic object works really well.
This is this placing or dispersing those waves and making them bounce back to the receiving antenna.
So yes, things that are organic are probably very good for radar because they absorb the energy a lot better so people like humans would tend to not be so good that wouldn't image.
Do you say people like humans? Yeah, humans, yeah, I guess and non-human people as well aliens.
They're stealthy and they have a thing that's that's been kind of going on about the you know windmills.
I don't know if you guys have windmills so much in the U.S.
Like the old fashioned kind of like the Dutch people.
No, no, no, not those. They'd be okay actually.
The new new school windmills the high speed.
We have them in some areas.
Yeah, so what happens is windmills cause lots and lots of problems for radar.
I'm not kidding.
Oh, no, I've heard this actually. Yeah, go ahead.
Yeah, yeah. So what they're doing is this is insane.
Is there actually because of the disruption to radar that windmills cause because of the way that windmills work in that they spin around and they disperse radio waves making it impossible to detect planes behind windmills because they basically stealthing out the planes and they're dispersing all this you know they kind of creating a scatter effect across the radar screen.
They're actually applying stealth technology from stealth fighters into the windtips of the windmills.
Yeah, no, seriously, they're actually making sure that the energy is absorbed in the right way and not dispersed so that when they're scanning the skies the windmills don't show up.
So they're trying to stealth out the windmills and yeah, I know it's quite incredible in a company in the UK called Kinetic is actually taking taking a frontier and this kind of project and actually creating stealth windmills which is the most bizarre thing I've ever heard.
But yeah, they're spending a lot of money like millions and millions and millions of of private company and public funds to actually devise ways of making windmills actually.
Oh, that's fascinating. Yeah, invisible to radar detection.
I have a mild radar related antidotes that I just thought of. I read a book once and I don't remember where it was but when the British first invented radar they didn't want the Germans to figure out what they were doing.
So they said that the reason they were detecting German planes approaching so from such a distance was that they had army soldiers, soldiers eating a lot of carrots because they're good for your eyes and looking through really powerful particulars. Yeah, that was kind of funny.
Yeah, yeah, no, that's that's true. I heard that as well and it's actually true that carrots are good for your eyes and there was there was kind of like an anti rumour rumour going about carrots don't make any difference but they do because the carrot in the carrots actually make your night vision better.
So both both those things are true and that they did say that carrots were fed to the to the soldiers to make them see better in the dark, which is how they were able to detect the planes because obviously there's no radar because radar is.
That's like on the memo because obviously there's no radar because that doesn't exist yet. Oh, okay. That's almost that. Yeah, exactly. So yeah, so yeah, it's it's it's quite funny.
But I think some of the some of the kind of cool things that that you tend to see well, there's no way you can kind of ever get your hands on it is obviously the satellite radar.
And a lot of people think about radar is those big kind of dishes that's been around. Yeah, I'm not talking about satellite.
But so yeah, I mean satellites have radar. One board for detecting variance in weather patterns and clouds and actually bouncing off radio waves.
Oh, yeah, it's off the surface of yeah, so it's off the surface of the earth and then anything that bounces back or that gets absorbed and that doesn't bounce back is obviously a cloud because the clouds will absorb radio waves.
And also spice off lights and this is where it kind of gets quite cool and quite, you know, MI6 is the 110 gigahertz range. The really quite small millimeter wave band is used for high resolution.
Not only meteorological observation, but also vehicles and any kind of high definition radar from satellites that's done from space.
So the space satellite uses rear that goes all the way down to earth and can detect a car and bounce that back. Yeah, exactly. That's really precise.
Yeah, it and it is. It's very high spec and the reason why they use those things is because they can't use optical radar so much because you can't ever guarantee if it's going to be a night.
And if you have a look at satellite imagery from space, there's always clouds in the way and Google maps and those kind of things are actually generally done by planes rather than satellites.
So those images that you see of streets and stuff are more than likely have been taken by a by a altitude plane rather than a satellite because if you have if you scroll out of Google maps, you tend to see kind of wisps of clouds and stuff that get in the way of actually imaging things that are on the ground and actually all the things that people are interested in seeing.
And they have to use this very high frequency, very narrow band radar to break through the cloud and image things that are below it, such as people and houses and cars and what have you missile silos or whatever.
Well, that's a good point. I never realized that you don't see any clouds on Google Earth and you're really kind of should.
Yeah, it's because they're not actually satellite images. They're planes.
Well, I knew they were playing images at a certain level, but I assumed there were probably more satellite imagery than there actually was because they always make a big deal about over launching this new satellite.
That's now point however they measure satellites, you know, with this new higher resolution.
And I imagine they can do some kind of patching where they take pictures where there aren't clouds and then just push them together.
But yeah, I guess the most were probably predominantly planes.
Yeah, they are. They're also, it's a mixture, I guess, of planes and satellite images and also different types of satellite images.
I think the companies actually do it at GOI or geo mapping PRC and there's other companies that Google pay for their satellite imagery.
There's also cryo-sat, which is a satellite that's a geo stationary satellite for mapping the ice caps of the North and South Poles and actually downloading scientific data for scientists to analyze based on the actual radio waves that bounce back off the ice caps so that scientists can see how deep they are.
And obviously how widespread they are. So you can see how, you know, global warming has an effect and then whatever.
Oh, that's useful.
So yeah, so satellite radar has lots of scientific applications to it.
So obviously being able to break through the ice caps and detect how deep they actually go and detecting heat.
So infrared radar detecting how warm the globe is or parts of parts of the globe.
You could use that to say, OK, so let's look at an area to see if there's any kind of underground activity or spying or whatever.
So millimeter band, you know, residents looking through things, looking through walls and actually bouncing radio waves from objects internally.
But that's more kind of back scatter stuff. So it's sort of what doesn't bounce back is probably a human or some sort of organic material.
And they would basically draw a picture of the things that are black rather than the things that bounce back as white.
So what is back scatter exactly?
OK, so back scatter radar or back scatter radar imaging is basically the deflection or the diffusion of radio waves to an object.
So if you shoot a line of radar waves at a ball, the radar waves will disperse.
And if you were receiving those rays to receiving antenna array, you could pick up a picture of what's being reflected or reflected or scattered of that actual object.
Now, another form of back scatter radar is high resolution imaging where you're slicing through an area with radar waves and whatever isn't being reflected or reflected back, that is being absorbed by some object probably and organic is what you're actually imaging.
So for example, X-ray is a perfect example of back scatter radar where the X-rays are generated by like a radioactive source or I think it's more actual electronic now rather than radioactive or however they do it now.
And the X-rays are shot through your body and your bones absorb the X-rays and all the X-rays that don't get absorbed get passed to a photographic film.
And the photographic film turns black if it gets exposed to X-rays and all the bits that don't get exposed remain white, which is where the picture of your bones come from.
And then that's how doctors can see if you've got broken bones because they'll be a little fine black hairline crack if you've got a kind of like a hairline break in your leg.
So yeah, that's kind of how back scatter radar works.
Oh, I see because here they're always advertising the airport scanner. So there's new millimeter wave scanner with back scatter technology.
Yeah, well that's that's I mean back scatter technology is basically the same thing as radar X-ray.
So X-ray is very high resolution imagery using a certain type of frequency of charge particles X-rays to be able to hit a photographic film surface to actually expose it.
All the areas that aren't exposed are left white. That's kind of how you draw a negative image of some of these leg or whatever.
So why is it that X-rays are so dangerous but backs about the millimeter waves aren't?
It's based well X-rays are isotopic particles which can have an effect if you have a long exposure to them to actually change your DNA not so much change your DNA in the kind of sense of like super hero type ship that it actually damages parts of your DNA.
So that when your DNA splits and informs new cells or whatever parts of the information DNA are lost which can cause cancer because maybe let's say the kill switch in DNA is lost.
That's kind of how cancer is because it's just a dividing dividing cell that yeah exactly we produce is never stops that's why it's dangerous but whereas millimeter or microwave radiation is not dangerous to you.
It's because it's not isotopic it's not it just creates heat it doesn't change your cell structure and that's probably why it's it's less dangerous but it can be dangerous in itself as well because obviously if you had a high enough wattage of the output of your millimeter radio waves you could cook somebody from the inside out.
Well that's fun to think about. When they say it's safe I'm 100% sure it's safe because you'd have to invest a lot of money to be able to you know like why they wouldn't just have like a chain of people going in and like hot chickens coming out sort of thing.
And the next thing to go to the airport I'm gonna look for a little knob going between like you know happy like person outline like a turkey with the little heat lines coming off of it.
Yeah yeah yeah 20 minutes and stir half way through.
So we need to just stand there for a couple more seconds so okay.
Yeah exactly but no I mean even when you're in a microwave oven obviously a microwave is powerful but you still have to spin the object rounds to get an even cook.
And also the microwave designed to scatter the radio waves back around in itself.
And if you just had a microwave generator just pointing in one direction it will be completely ineffective.
In fact you probably wouldn't even feel it because it's not a focused energy but if you as soon as you cone that energy back into like a like a megaphone let's say that's when it becomes dangerous because it's it's scattering those rays
in a in a focused direction towards an object.
And that's if you leave a microwave on by itself without anything inside it I think it starts the buzz and it starts of you see little bits of lightning go across and stuff.
And that's because the radio waves is being so tightly packed that they're starting to bounce off and generate kind of plasma and shit inside.
It's pretty cool if you leave like a spoon or something in the microwave.
You know if you put a CD in the microwave for just less than a second it develops this cool fractal lines on it.
Yeah exactly yeah yeah and that's the that's the energy dispersed across the film because it's sort of like a very thin wafer of metallic.
I don't know some sort of fabric that's that's on the top half of the CD which is sort of underneath the layer of the label.
And that's where the radio waves smash into and cause that kind of fractalization.
You know a friend of mine used to work at a bar and there's this one like older guy in his 50s or 60s that always come in and he'd leave these outrageously huge tips like 60s 70 dollars.
And it turns out that he was the guy who invented the first mesh that goes in front of microwaves to prevent the microwave from coming up but you can still look in to see your food cooking.
It's like a multi-billion or an hour or whatever.
How does that mesh work? It's not like in it's not entirely complete that has holes in it.
How does it absorb so much of the microwave energy?
Okay so that's the kind of the principle like a Faraday cage is supposed.
Oh I suppose that's true isn't it? Because a Faraday cage is very see-through.
Yeah a Faraday cage is see-through in that. It's see-through because it doesn't have to be complete because the electricity or lightning will strike the part of the Baraday cage which is the shortest bathed earth.
Yeah as long as it's a complete mesh it will always go down to the shortest bath.
The way that sort of like a tempest mesh tempest is a US standard for radio isolation.
It has to be the actual gaps have to be a certain width apart for the type of radio waves that you're trying to block.
So one mesh does not fit all. One mesh will allow some waves to pass and others not.
So for like blocking let's say radio waves you need six to seven centimeters sorry millimeters two centimeters for high frequencies and larger gaps for shorter frequencies.
So obviously depends you have to apply the mesh gap with for the right frequency that you're trying to block.
Wow so is this like was this one of your things like in college or your career like you studied radio waves is just a hobby for you.
Oh no just a hobby there.
Really oh wow this is impressive. I get you to help me fix an amp that I can't get working.
Yes well this was extremely fun. I thought you were just going to talk about radar but this was a whole bunch of fun stuff.
I feel great now I learned about your stuff. Do you have anything else to add if not I like to keep it under 45 minutes or so if I can.
Yeah that was fine. I guess not no I mean there's it's quite a varied world when you get into radio frequency.
And I think if your listeners are interested in the kind of topics that I've just discussed to definitely go on and learn about ham radio because it's a real kind of step into the world of VHF and UHF and all sorts of things.
I've always wanted to get into ham radio.
So you know it's kind of an area of amateur hacking that isn't really kind of I guess as popular as freaking or computer hacking or programming.
But it's also an area of great amount of possibilities of being able to tinker with various things.
And when you start talking about radio telephony and actually communicating with computers across radio modems you know that's kind of an excellent level.
Yeah exactly and people like some of the guys that I go to 2600 meetings and talk to they have no idea that you can just call up a radio and send it streams across and have you know packet radio internet access.
Do you have like repeat your networks there to know especially the west coast you do.
Yeah we have them all over the place all over the UK.
Oh that's cool I've always wanted to get into that but I haven't mostly I haven't been able to figure out where to invest all the money in the equipment.
Do you have a recommendation for entry level ham radio equipment like a good brand trust or anything.
Yeah I guess Icom is probably quite good but they tend to be expensive.
So Bearcat Uniden Icom those are two brand brands that I would say are probably good.
I mean start small obviously don't spend you know $6,000 on a base station and you know get completely confused about all the different buttons.
Start small by yourself like a small like a handheld.
Airband handheld receiver that covers maybe 10 megahertz all the way to 600 megahertz and that's more than enough for you to get listening on radio waves.
You'll start learning different things I mean you'll be able to pick up page your radio and also stuff.
Oh yeah I got to get you to come back on talk about intercepting pages that sounds fun.
Yeah we'll have to talk about that some other time actually because that's quite a big topic in itself I think.
Oh well this is good we have other stuff like this.
Okay well let's end now because I tried to pick five minutes ago and I dragged on I'm sorry.
Okay well then thanks for being here and I hope you'll come back in the future.
Yeah I hope so too hopefully you get some feedback and maybe some people enjoyed this.