Episode: 2000
Title: HPR2000: How to Point a Satellite Dish
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2000/hpr2000.mp3
Transcribed: 2025-10-18 13:08:33

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This episode of HPR is brought to you by Ananasthost.com.
Get 15% discount on all shared hosting with the offer code HPR15.
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Hi folks, this is Ken and you're listening to Hacker Public Radio.
Today is special tradition dictates that I do a show, and yes, today's show is Hacker Public Radio Episode 2000.
Okay, it's actually 2,300, including today with the techy shows, but a tradition is a tradition.
Deciding on what we would do to mark the occasion, I have decided to honor the most dedicated
companion of HPR down through the years. Someone who has been there with every host,
every contributor, every listener who's thought of recording a show.
Yes folks, it's our old nemesis pro-crustination.
So, if you ever end up volunteering to do the administration here in HPR,
every so often you'll get contacted with a message along the lines of,
you know, I was thinking of doing a show on a very interesting topic and it might turn out to be
a series. This has happened so often down to the years, even in the interview with droops,
you mentioned it, that the motto has, there's a motto here, it's not a show until it's on the
server, so you don't actually care. All it takes for a show to be accepted by HPR is two people
to find it interesting, and as you know, Dave and I find all the shows interesting, so including
yourself, that's one over the quarter. So, we tracked down the worst possible procrastinator on
the network, and this person is regularly on social media, IRC, his own blog, and even on the
new year's show itself, telling everybody what shows they intend to do next year and why they didn't
do the show, blah, blah, blah, blah. So, I'll read out an email verbatim, and I want you to pay
particular attention to the date that I was sent.
Wow, so folks, that was 11 years ago, 13th of December 2005. So, who was this person? Who do we
need to track down for this? Yes, no other than my good self. Yes, I told droops, I would send
an initial and did I ever know. And so, therefore, for episode 2000, to mark the occasion, I have
recorded this show, and to be honest, I have been jinxed with this. There's two aspects to it.
One is when I'm researching the topic, give me some background. When I joined, when I came over
to the Netherlands, the first job I got was in a satellite ISP. We were resellers to, we were
providing the uplink for other satellites into ISPs. At the time, there was very little broadband,
even in the Netherlands, which was one of the highest penetrations of broadband in the world.
There was only about 5% of people at broadband. Since then, DSL, Camelon and cable networks
got their act together and stuff. But at the time, it was a viable alternative. I was actually
working on content distribution. I was actually a Windows admin back then. Anyway,
it was actually there that I got my first introduction to Linux because the whole system was based
on Linux, written in Pearl, actually, believe it or not. So, what would happen is,
you as an end customer have a satellite card in your computer or a satellite router. And that's
got a MAC address. And it listens to an incoming signal from a satellite. We'll talk more about that
in a minute. And it listens for the stuff destined for its MAC address. Now, that might come from
a point-point connection. So, something only for that MAC address or it might be for something
that is just subcribed to an multi-cast network. So, it is a joined group or we've joined it to a group
and we're sending it out. So, that for the group transmission, say, at the time a big thing was
digital cinema and the question was, how are we going to send down those files? And the idea was
that there would be satellite dishes and old cinemas. You go into a multi-cast group and all the
cinemas would receive the movie at the same time. So, that was pretty cool. But satellite internet
continues to be an extension, especially the DVB standard, which is the digital video broadcasting
standard, which is what sky and a lot of the satellite TV providers, at least here in Europe,
use I know in the US to use something similar. And it allows data packets to be sent down there.
So, what you would do is on your dial-up modem, you get a free dial-up disk at the time from AOL
or whatever you put it into your computer, you use your modem, and you would connect to the internet
over that. And usually these were free-form services and you would be able to use them for
a period of time. Then, you would start a GRE tunnel, which would be a VPN connection and we didn't
encrypt the connection or anything, but all it allowed us to do was do an IP connection over the
internet. And this is a basic Windows package for business. And that would connect to our platform,
and then you would now be routing all your packets to our Oplink station. So, you log in,
log in password, and we will have your MAC address of your DVB card. You would send a request
www.altervista at the time. And the request would go toaltervista, go to be sent over the GRE tunnel
to us. We were proxy it out toaltervista, we would get our reply back. And instead of sending
it back down to you on IP tables, simply send it over to the address of the router. And the router
would take it and put it into a tanberg, which was multi-gaster, sorry, multiplexer. And if we get
sent out to the satellite, the satellite or broadcast it, send it down to everybody, basically.
Everybody else would ignore us. You were tuned in on that satellite and that frequency,
and you MAC address, would listen to that, and it would take the packets in. The TCP IP,
being a layered level, the layers underneath her, stripped off, and just passed off. And all that,
the browser knows is that it sent a request with this window, with this ID, and it got a reply
back from this ID. And it had no understanding of what happened underneath and it didn't care.
So it actually works very well because you got fairly high bandwidth throughput rates,
so long as there was, it wouldn't be great for lag because you click a button and it takes
half a second for it to go out to the satellites and back. So, you know, that's not very good for
games, but if you're starting a download of a movie or something, you know, that half a second
that comes down at the time, like people were running really slow connections, half a mega
connections. If they were lucky, you get 23 megabits per second, if the satellite was empty.
What shouted in the force was the rule out of broadband, and people trying to make profit,
because this is very expensive, it's very expensive to us, you have to pay the uplink provider.
And also, you had to, basically, everybody wanted to use the system at the same time,
which meant it was the contention ratios were very, very high, and you send a request and you only
get a small piece of the bandwidth. So, that's that. So, let's first of all talk about the basics here.
First of all, what is an orbit? We need to talk about satellites orbiting the planet. So,
first of all, what an orbit is. So, if you take a football and you take it, it doesn't matter if it's
around on or funny shape on, it will orbit the planet and then fall back to Earth. If you roll
it along the ground, it doesn't, but if you throw it, it has a forward momentum, and then eventually,
it will fall down. So, if you have a better football player and they kicked the ball further,
or throw the ball if you're a American football player, it will go further before falls down,
such as a bigger orbit than the other one. The fact that it hits the Earth doesn't actually matter
as such from the point of view of orbits, it just happens. So, this guy called Isaac Newton,
you might have heard him, had this idea that the pilot experiments, so that you build a tower
anywhere on the Earth, it doesn't matter. Let's say we go up to Mount Everest, the top of Mount Everest,
and we carry with us a gun, and we fire that gun, and we fire it in any direction, it doesn't matter.
What happens is that bullet goes out, keeps going firing, firing, firing, it's going forward,
and it continues to go forward, but eventually gravity catches us and it goes down.
But if you were going, if fired a gun, maybe it had a little missile and such, it had a
little engine and started going forward, faster and faster and faster, the rate of which it falls
would eventually get to be the same circumference as the Earth. Then you had an even faster one,
more powerful gun, and you fired it off. Then it would actually fire straight off into space,
at a particular point in time, it's going so fast that the effect of gravity gets less and less
and less and less, so it curves down a little bit, but eventually heads off into space where the
Earth's gravity ceases to have an effect or not. But it's that happy little interesting one in
between, that is the orbit one, so what we think of as an orbit, where it goes round and round
and round and round, and the key part of that is, basically you're falling the whole time.
Sometimes it might think, you know, you think of an orbit as going around the Earth,
just turn your mind 90 degrees and imagine you falling straight off
of Mount Everest. No, that does not make any sense, but in order to orbit, you need to go
on at a particular speed. So if you're like in the International Space Station, for instance,
so let's break down these orbits first. You have no orbit, which is like your football thing,
suborbital trajectories, which is like a is where you basically go up for a good bit and then come
down without actually going around the Earth. The trajectory intersects the atmosphere, so that
is not complete one orbital revolution. Orbital trajectories, which are the ones that we were
talking about, and escape trajectories where your orbit and you leave the planet
or body or whatever moon or whatever happened to be orbiting it. At this point in time for the
purpose of the last HPR has a listenership that I'm not aware of. We're talking about people on
the planet Earth at the moment. So a lot of this information has come from Wikipedia. I'm one
of the main reasons why I had so much trouble doing this show is that it is such an interesting
topic for me. I cannot stop clicking links and stuff. So I've had to be really focused for the last
three days because I know this is coming up and this is the last time I'm going to get a chance to
record it. I actually am doing a second part to this, which I'm going to take the recorder here
and just head straight up onto the roof. I'm going to press pause, walk up on the roof and then
continue recording this thing. So hopefully it will get submitted automatically after I'm done
that. Anyway, then where are we? Yes, orbital position. It's worth noting that. So when you fire
off a rocket, first of all, it goes vertically just to get out of the atmosphere. But once it's
gone up and off, it starts tilting and then tilting into orbits. So once an orbit keeps
their speed in the atmosphere and elliptical orbit dips into the denser the object will lose speed
and reenter. Occasionally, a spacecraft will intentionally intercept the atmosphere and we
come in and refer to as an aerobracking maneuver. So that's how they slow down spaceships come in.
But basically, they, something like the International Space Station, as it rotates, it's
I think 340 kilometers above earth that loses 90 meters a day. So 90 meters a day, like size
of a football pitch, I guess, having no idea how long a football pitch is. Okay, well, whatever.
So that occasionally has to fire its thrusters, onboard engines, in order to raise it above,
bring it to a higher orbit. And when it's refueled or refueling station comes, they will fire
their rockets and give it a bit of a bump to get it even higher into the, give it a higher orbit.
So there are lots of ways of defining orbits. And if there was only somebody with a, I don't know,
maybe a Scottish accent, who perhaps is professional in dealing with the night sky and all of the stuff
could talk to us about orbits and other cool things that I was talking about. Sorry, sorry,
anyway, types of orbits. So they're basically the type of orbit that you pick is depending on
what, depending really on what you want the satellite to do. So here are some of the classifications,
a centric classification. So it's based on what the orbit, an altitude classification,
based on how high they are. And that's the most common one, inclination classification,
based on the rotation above the equator or, you know, honorable of the equator,
eccentricity, which is based on their path is a circular or elliptical or like hyper elliptical
or whatever. And synchronicity. So based on how often they rotate. So often you'll have a
combination of several of these describing a particular satellite that it's in one or the other.
So let's, let's go through the altitude ones, which are the most important ones, I think.
By far, most of the satellites are in low earth orbit or Leo, as they call it. And that
goes from zero to two thousand kilometers. So zero to one point to, sorry, one thousand two
hundred and forty miles. So it starts at sea level and the first band is to the maximum height
that a self propelled jet aircraft has ever gone, which was set in 1970, record set in 1977.
And that is 37.6 kilometers or 23.4 miles. Now, the first artificial satellite was Sputnik-1
and that got up to two hundred and fifteen kilometers, which is 133.6 miles. Think about this,
that when you're thinking about these, how far the satellites are, like,
lower orbit satellites are really not that far away at all. As I said before,
three hundred and forty kilometers is where the International Space Station is two hundred and eleven
miles. Mere used to be at three ninety kilometers, two forty two. The Hubble Space Telescope is up
there at five nine five kilometers, which is three six nine miles. And the reason for the Hubble
Telescope being up there is because, and again, got distracted about this one, because our
atmosphere filters out an awful lot of the wavelengths. So only, like we see sunlight and radio
signals are basically all that comes through the atmosphere. So if you want to examine any other
of the wavelengths, electromagnetic spectrum outside of that, then you got to get your
satellite up our your telescope up into space. So that's why that has been able to give such
fantastic images, because it's not limited by the relatively small amount of the spectrum that we
can see. Again, no expert on this. It's just this pretty much is just me getting very interested
on this topic. So this is, you can classify this whole topic as Ken's wish list for stuff. If
anyone knows anything more about these. So
then we have satellites that orbit the earth in near exact polar orbits, north to south,
across the equation, multiple times each day, and they are at the same angle with respect to the
sun. Satellite on these type of orbits are particularly useful for capturing images of
earth surfaces and images of the sun. So as they go around, you will they take a picture of a
building so the shadow was always on the same side of the same building. And these are also used
for the iridium satellites. They also have a low earth orbit and they orbit around the
pole, the north pole. So north to south pole. Those are basically if you think of the way a
cellular mobile network operates, those operate in a similar way except that instead of you being
in a training being passed from one base station to the next base station, the base stations happen
to be in the sky. And as you are talking, they move across the sky at quite high speeds and then
you switch from one to the next. Which is why you get satellite communication over radium
foam is possible anywhere on the earth. And it is also religiously expensive. So there you go,
that's that. Then the other type is medium earth orbit and that goes from 2,000 kilometers,
1,240 miles to up to where geosynchronous orbits is at 35,786 kilometers, which is 222,236 miles.
Now you may ask yourself, well, the definition of lower orbit and medium earth orbit was like
nice to 2,000 miles. Why suddenly have we got this weird, very specific down to the last
kilometer, down to the last mile thing. But before we go to that, let's talk to medium earth orbits.
These are usually the ones over here are GPS, global positioning satellites. And they have
an interesting thing is that they rotate around the earth exactly 12, two times a day, every 12
hours they rotate around the earth. So that is a feature that they make use of.
So why this very specific band for what is the next category, which is geosynchronous orbits or
geostationary orbits. So back in the 60s, this guy called Arthur C. Clarke came up with this idea
that, you know, you have this area where you have the rhythm satellites are spinning, spinning or
let's say the International Space Station circles the earth several times a day because it has to
go so fast. It's constantly falling and its forward trajectory keeps it moving and it falls
in the same angle as the earth. But if you go further out to the moon, for instance, it is still
forcing along at a mighty rate of knots. That's a technical turn there for you. It's falling as well
in respect to the earth. And it is, but it is revolving around the earth as a interval of 30 days.
So somewhere in between those two, the higher up you go, the less times you revolve the earth revolve
around the earth on a particular time. In order to be in a particular orbit, you need to maintain
a particular speed. So if you go higher, then you need to maintain a slower, slightly slower speed,
but the number of times you revolve around the earth decreases. Tell such a point where it is,
you revolve around the earth once a day. Okay, that's interesting. Why is that interesting? Can
everybody is going please? We know this. Okay, anyway, it's interesting because from your point of
view on earth, you're revolving and if you stick out your hand, and on your hand, you are holding
a satellite. And as you're revolving, the satellite is also falling at the same rate at which you're
revolving. But if you look out there, it always seems to be in the same space in the sky, which is what
means a geostationary orbit while it's geosynchronous. So the difference between a geostationary orbit and
a geosynchronous orbit is a geostationary orbit is over the equator. And what that means is that as
the earth revolves around during the day, it still appears to be in the same spot, whereas geosynchronous
and not geostationary means it can revolve up and down during the day. So the angle of inclination
is not necessarily the horizon. So as you look at it, it looks like the satellite is bouncing up
and down during the day because the earth is tilted and as it rotates, the tilt of the earth
goes around. So from your point of view, the satellite is going down and then goes up.
The same way that the sun goes up and down in the sky, it's due to the angle of
angle of rotation or angle of inclination of the of the earth. For all you flat earthers out there,
sorry, RIP territory branches, but turtles all the way down.
So why would that be useful? Why would they it going up and down be useful? Well, it turns out
Japan has geostationary satellite over there, which they're using for a global positioning system
themselves. Well, it's not it's a regional positioning system. And again, it changes twice
in the one day. I have no idea if that actually has any significance or not, but it probably has.
So people constantly are doing cool things with these orbits because they can.
So for geostationary orbits, what that means is that, well, let's just take, if you want to
communicate with any of the amateur radio satellites, which are out there small, the operation
law earth orbits, and they're usually sent up when they fill up the spaces and they get sent out.
They are tearing around the earth and they're basically falling. In order to pick them up,
you need to track them with a beam and you can track them as they go across the sky and they go
quite fast. International Space Station also only appears I think for 10 minutes in the sky
at any given time and you have to track it from left to right. Imagine if you wanted to watch
some TV and the satellite only appears every few hours and only for 10 minutes at a time that would
be a rather annoying proof. So for for TV communications, it's very advantageous to have
two things. One is small dish that you don't need to point. And two, that your dish is fixed.
So you put it up and you forget about it. So that's where geostationary satellites really come
into their own, they're there at one point. The fact that they operate at the frequency is the
operator which I'm not going to get into. I'm not this show will never end if I do.
And means that they have a higher bandwidth. Boss, they're more susceptible to rain and cloud
interference. But as it happens, it it seems to work out okay. So the last classification
with relates to altitude is anything above geosynchronous orbit is considered to be a high earth
orbit. There are a few more that I want to mention. The graveyard orbit is what happens when they
have satellites that they don't want anymore instead of sending them back to earth, which would cost
fuel. They push them to a higher orbit with the last remaining fuel that pushed them out of the
way and basically let's hope it doesn't come down a little bit above. So some other cool orbits
polar orbit way of of describing polar or orbits. Another one that I find interesting is polar orbits
which you which you use for earth mapping, earth observation, spying, capturing earth from time to
time from one point, spying, and weather satellites. So the aridum satellite constellation uses polar
orbit to provide telecommunications services. The disadvantage of this orbit is that one spot on
the earth's surface can be sensed continuously from the satellite in the polar orbit that no one
point can be but it does cover or it can cover all the areas of the earth. So that's handy for weather.
Now I was telling you about advantageous of having a fixed-ish pointing for TV. Now say you had a
that's fine. So that means it needs to be in geostationary orbit on the equator. Well that's fine but
for the north you go the more you have to point your dish down. And the whole point of satellite
communication is that it is designed to dizzy chain signals from one place to the other. So you've
got think in the Netherlands there's a whole the Netherlands being flat for those of you who
haven't done geography. It's flat and in order to communicate the government during the Cold War
built tall towers that were 300 meters higher so and these towers independently communicate it
with each other so that if anyone was taken out then the rest would the signals would carry through
and that works fine because they can see each other but eventually you've got the curvature of the
earth comes into play again again sorry for the flat workers and you can't get a signal from
one place to the other. In places that are not deprived of geography like are deprived of the
third dimension where they have mountains you solution is to put the radio TV broadcast tower
on the top of the mountains broadcast to people but sometimes people are in a valley or the other
side of a hill and they get very poor reception. Satellites solve this problem because with three
satellites you can theoretically broadcast to all places of the earth so signal going from one to
the next and you can also bounce signals off satellites themselves so satellite over Asia
can see a satellite over Europe and can retransmit that to a satellite over the US and send the signal
back down so that's how you know live up links are quite often done. However say you are a the
Soviet Union and you got some pretty cool guys who know how to put stuff into space and you got
a lot of your population who are in the northern hemisphere over on Serbia and so what are you going
to do? Well you come up with the Molja Molnia orbit. Let me just play that for you. Molnia. One more time.
Molnia. Molnia orbit which means lightning in Russian. This is the coolest orbit ever. Now I don't
know if you have ever had those paddle games with an elastic band and a ball on it and you go
and if you're good you can do it against your face and the ball goes out and then it comes back goes
out and if you do that over your right eye without it in your right eye on your left eye you can
still see the ball more or less stays in the same place it gets bigger and smaller and bigger and
smaller but more or less stays in the same place right this is how this orbit works. You have three
satellites they're spinning around the earth they're not in an elliptical orbit around the center
they're spinning around in a highly a highly blue orbit so they come very close to the earth
on the on the way in and they go very far away they're caught by the gravity and then they come
back and they go speeding around and then they go out again so the journey out and the journey in
are very are appear the satellites appear in range for quite a long time so as one is going out
the other ones coming back and the third one is disappearing not only that but the earth is rotating
as well and they're with the wobble they're picking up the satellite wobbles and it is from the
point of view of the satellite it looks like the the piece of land that is that it's aiming at is
rotating not not with the rotation of the earth but rotating with the wobble so it goes round
like you would screw in a light bulb or something round over and back over and back. There are some
animations on this it is I think one of the most underestimated achievements that was how they
were able to bring the orbiter system online which consisted of three highly elliptical
monia satellites, musco based ground uplink facilities and 20 downing stations located in cities
and towns in the remote regions of Serbia and the Far East. Each station had 12 meter
receiving parabolic antenna and transmitters for re-broadcasting TV signals to local households
that is absolutely awesome. So I've included a link of the to that as well that's just my personal
you see how we get distracted with this you know this is why the show is not been done that and
Murphy is very strong in this show everything that can go I've tried to record this
umpteen times down through the last 11 years. But anyway yes there's a nice two-scale sgv of
orbital attitudes and you can see on that where exactly all these orbits are even from the point
of view of earth. Let me see the medium earth orbit it would be about four two or three
sizes of the earth away is where geosynchronous orbits are and there that's about 10th of the
way to the moon which is very far away by the way if you look at the story. Anyway speaking of
cool people with space technology we can't talk about satellites so we don't orbit satellites now
without talking about Sputnik 1 which was the very first artificial satellite Soviet Union and
this come from Wikipedia page so all the opinions are from here. The Soviet Union struggling not to
do a Russian accent launched is on a optical low earth orbit on October the 4th 1957 it was 58 centimeters
23 inches diameter polished metal sphere with four external radio antenna to broadcast radio pulses
it was visible all around the earth and the radio pulses were detectable. This surprise success
precipitated the American Sputnik crisis and triggered the space rays a part of the larger
Cold War the launch ushered in new political military technological and scientific developments
so yes okay what makes up the components of a satellite I was actually this is one of the things
when we had an internal class when I worked at the satellite company and it was one of the most
interesting classes that we had about you know what what issues you have with with a satellite
getting it into space and I have not been able to get a copy of that presentation the guy wanted
to give it to me but couldn't find it anymore and also getting information on the actual components
of a satellite you go from extremely simplified to no we're not kind of sharing that information with
but basically a typical satellite will well communication satellite here I have no idea what
other satellites have they have rocket motors to maneuver left right and open down every so
often you try and then you have fuel tanks solar panels batteries on board computer and antennas
transceivers or transponders what determines the lifespan of a satellite is not
the technology on board because it will always be somebody when they when they launch a satellite
they always try and put a much new technology into it the best compression or the best
transponders densest they've got lots of tricks for getting an optimal footprint and all that sort
of thing but at a particular point in time they need to keep the satellites in a particular box
so you go to the ITC you and I've got a picture from the Boeing commercial satellite
commercial boom commercial communication satellite geosynchronous orbits and it gives you
all the allocated satellites from the ITC you and where they are so each of them are given a slot
and some of those slots are incredibly desirable over populated areas and then you have other places
like in the middle of the Pacific where there's nothing no satellites at all that's not to say
that those positions are not used but you have no satellites at all over there because you put
the satellites where you are going to have them be able to use them so for example
here we have satellites two degrees three degrees four degrees five degrees seven degrees apart
so you know a degree or something like that once you get a slot you are required to operate in a
box which is 18 kilometers by 18 kilometers by 18 kilometers well not by 18 kilometers but a
box of 18 kilometers by 18 kilometers and these orbits are not pure they're elliptical as in
they they come in and go out from earth about 300 kilometers depending so that's pretty much okay
but the position east and west is important for an operator to keep their satellites there because
the fixed antenna are there and you don't want to be moving drift in your satellite so satellite
drift is a big thing your satellite drifts into your neighboring slot and then suddenly somebody who
expects to have a narrow big channel is suddenly getting a Hindi channel or something so you
you're required to keep it into a box the more stable in order to do that if it starts drifting so
it hits particles and stuff that affects it or there's an earthquake on earth which suddenly
turns the earth around this region then all the satellites need to be we adjusted to account for
that and so the satellites are in this box thing as they call it and in order to keep them in
there they need to fire rockets to keep them orientated correctly those rockets require fuel
and the cost of refueling a satellite is more expensive than it will be to put a new satellite
up which got newer stuff in your kit so the worth of a satellite is based on a its position
be how much fuel is gotten bored and when they're doing when they launch a satellite they launch it
in a in a low earth or in medium earth low medium earth orbit and then they will fire the
onboard make sure everything's okay then the fire is send it into an elliptical order that sends it
in to the earth and out further and out further until it gets Gs synchronous orbit then they'll
burn some fuel to keep it into a Gs synchronous orbit and what they will usually do is park them for a
while somewhere over the Pacific or somewhere so they can test them and basically it's just hovering
over the Pacific and then when they want to move it into position what they'll do is they'll slow it
down the fire a little bit of fuel they'll slow it down so that it passes slowly the earth it's
revolving slightly less fast than the earth is and then it will catch up with position they'll
fire the rocket again speed it up bump it up that little bit slow it down that little bit bump it
up that little bit everything everything is based in conservation of fuel because the more fuel
that you can save the more money you can make from your satellite and once your satellite is no
longer you're no longer able to keep it into the 18 kilometer box for Gs synchronous stuff you'll
send it off somewhere else to another orbit where it doesn't the where they've got a lot more
free space on both sides so where it needs a a larger antenna to receive it and then as it loses
fuel on the 18 kilometer box then in order to track it you would need to have a moving satellite
dish so that brings maybe into that might be so useful for end to end customers but as a business
if you're operating on an oil rig then you might take some transponders on one of those satellites
and have your moving antenna follow this satellite so you'll be able to get a lot of bandwidth
to your oil rig for a very cheap price so a lot of that trading goes on just so you know
so other components of but basically what as what a satellite is so we got a we got solar panels
so 40 meter or once it goes out into space the solar panels come out and they are 40 meter
panels and they charge batteries and the battery charge compute the onboard electronics which
probably is computers and they keep the old thing going now you have several people might be broadcasting
to a particular satellite and what a satellite is is is like a huge tall radio tower in the sky
it takes in signals from one place and it sends them out on the other and I'll put a link in the
show notes that has got more more technical breakdown on how transponders work so let me just
so the word transponders derived from the word transmissor and responder a communication satellite
transponder is a series of interconnected units that form a communication channel between the
receiving and the transmitting antenna it's mainly used in satellite communications to transfer
the received signals a transponder consists of an input limiting device a low pass filter
an input low noise amplifier LNA designed to amplify the normally very weak because of the large
distances involved signals received from the earth station a frequency translate turns later
normally composed of an oscillator and a frequency mixer used to convert the frequency of the
received signal to the frequency required for the transmitted signal and then an output bypass filter
and a power amplifier this can be a traveling wave tube or a solid state amplifier and for more
information on that see the link that I put into the show notes you basically received a
a signal in on a particular frequency and then that's down on from the oplink and that's
downlinked on another frequency so what the satellite operations will do is they'll have the most
of the astrofleet and quite a lot of the SES astrofleet is managed by SES astro which are in
Luxembourg and I was lucky enough to have a site visit there one time which is pretty impressive
and they control the physical location of the satellite you know where it is in the box and stuff
and when when they need to do a burn and when they don't need to do a burn and they will allocate
to say to the BBC or free sass which we're going to be talking about now which is a a broadcaster
so it's free to air satellite communications for the UK so they will allocate certain
transponders and frequency codes for them and they will broadcast the oplink on those frequencies
and then on their their website they will publish here are they're receiving frequencies for
for these transponders so you will buy a transponder or several transponders and then
let's up to you to divvy it up so if you're using analog TV you're going to maybe
be able to get four channels in there if you're using MPEG 2 you might be able to get 8 MPEG 4 you
might be able to get 16 so that's why all those technologies are quite interesting from a
broadcast point of view but the same number of bits going through the satellite is quite important
from a data point of view when you're sending data through one of the main one of the main issues
they have with satellites is as well as the fuel is they is the terminal issues that they have
it goes from 100 and something degrees Celsius 150 degrees Celsius to minus 150 degrees during
the rotation of the thing and that's very stressful on the on the satellite itself but what they
noticed as well was when they were sending data through mostly when you're not transmitting or
there was an exceptional bias to zeros and of course zeros means you're not transmitting
anything so if you're not transmitting anything things get cold and once you start sending ones
things get hot so you had this massive massive terminal the satellites were not lasting as
long as they thought the wood because of the terminal impact of going from you know a quiet time
in the evening you know when you're when it's nighttime to suddenly boom you're on during the
never counted for that so now built into the dbb specification dbbs specification between the
uplink and the satellites and of course the downlink they have an algorithm put in there so that
they're always transmitting bytes sort of semi randomly that there will always be more or less
equal number of ones than equal number of zeros so they've built that into the the whole system
another cool thing they do is that they'll it's polarized so a low noise black
so they will have a big tracking station just transmit up in the microwave KU band
which you can look this up as well what that actually means in gigahertz
and then it'll be sent down to your receiver your receiver is a parabolic dish you know
ship like a a plate or a bowl and that focuses the beams in to a particular point and at that
point you have a low noise black down device which takes the high frequency signals and converts
them into lower frequencies they can be sent over a short coaxial cable oh gosh I've said that
about 15,000 times for recording this show but there you know that's that's what it does
and then you can bring that into your house and into your satellite equipment and again later on
we'll do I go up on the roof and I'll actually do the pointing of the of the dish so one of the
cool things to do there though is there's a they also use the fact that you can polarize you can
polarize a signal you have a horizontal vertical now as far as I know it's not actually horizontal
vertical it's more like an ellipse spiral helix that goes down but I will leave that up to one
of my the hammer radio enthusiasts to talk to us about that so that is basically how satellites
operate and then it comes into a receiving device the signal comes into a set of box you can also
have USB ones I've got one here and I've got old PCI cards that you can use or a regular satellite
receiving box if you just want to receive TV receiving and listening onto a satellite if you're
into this sort of thing is really cool because a lot of the stuff is not encrypted and even you can
see the packets going past and it's it's just interesting from a understanding a DVB protocol
put in a wire shark on there and you can see like people you know what people are doing if they're
surfing the internet and that sort of thing I think a lot that isn't is now encrypted and so
there's a lot less of that going on but back in the day it was before Wi-Fi open Wi-Fi points were
were available you it was just mind blowing to be able to see all the stuff the people
were were watching and using the services for and so that goes into the
pointing a satellite dish so we will talk about that outside and I've got a link to the dish
pointer site and they and they print out of what I'm just going to use now in a minute to
to point the dish I'm going to be going to the Astra 28.2 East or Euro Hubbard
fleet of satellites which is the free sat ones and there's a list of those they're
co-located so there was
SES Astra operates the Astra 2e 2f and 2g satellites from there the the drop down box
shows that 2a 2c 2d and 2f were operating at that time so 2d and 2a 2a has been decommissioned
so it's been moved up to a graveyard one and 2c has been sold on to somebody else and they get
renamed so when you hear about new satellite launch new satellite for blah blah blah service means
it could be some other satellite that's a end of life for somebody else I've also linked in a
pretty pretty cool page on how to get mid TV working with with DVBS so free sat HD
and what hardware you need up case update update install DVBS and then player and then you just
scan user share DVBS and Astra 2e which has got all the information you need into your channels.conf
file and if you've done any DVBS stuff at all this is very very similar and so that's all
pretty cool and you can then start watching TV or you can start doing ISP stuff so
people who are using satellite internet might want to record us a little show and see how that
goes so some of the things we're going to need for part of this is the azimuth which the distance
from north altitude or in our thing it's elevation which is the distance from the equator up
and let me just pause this right now
I don't I really don't believe this this is now the third time I had to record this the first time
the batteries ran out the second time I had the double record
zoom hitch to bug right I don't have a choice but to continue recording this because this show has
to be released and there's no way to stop it the day I picked happens to be the most windy day
and when I just step out here there's happens to be a force and a gale going on at the minus
and two of my panels have already fallen down the neighbor's roof has come off and they've got
sandbags up there to stop the roof falling off so anyway over here to explain to you is how the
internet's appointed a satellite station it's not something that I ever was up to do the good
at mostly because there's three things about you need to get the the location of the satellite
east of west where it's located we need to point based on elevation then you need to just
for polarization but I'll try put on a even sound
and before I go I need to remember to clean out that cover
dry the other half there's a mention of water analysis where it's plugged up with
I'm still recording okay fine anyway a satellite dish is actually quite reasonably cheap you can
buy a card for 28 euros or so for a cheap USB satellite card devices you can buy a whole case
including the satellite dish and stand and the receiver for 150 euros dollars you know in the
ballpark so 200 euros you'll have yourself a good kit and there's a lot of reasons to get that
like a free sat in the UK we're just in the boundary of a free sat here and you can
get a lot of UK and Irish programming free to air and so the three things that you need to know
about when pointing a satellite we've already covered elevation azimuth which is how much left
and right basically elevation is so much up and down and the last thing is the skew
now back in the day if you are pointing a satellite dish the best thing to do is get your stand
correct if you use an portable stand if you put it on the level surface you're good
if you're attaching it to the wall make sure it's 100% vertical in all directions that will
make your life a lot easier so that that will get that out of the way I have a satellite
finder which connects between the LMB which is the low noise blockter down device or
the low noise block they always call this but it's the thing for converting microwave signals
down into the range that can be carried across a coaxial cable you know coaxial cable will connect
with a it's a sort of higher quality cable thanks 75 ohms and the impedance and it has got
I'm not 100% sure about that and it's got an f-type connector so that's like a screwing connector
on it so that's you'll have a little cable go into the satellite finder and the satellite finder
then we'll go to the set box or some other device to give it power it needs a certain number of
volts in order to operate which you'll find anyway the it's so the first thing you do is you find
you need to know where you are so you need to refer to the footprint satellite footprint
and on the satellite footprint is basically a map of the world are they footprint of
of the satellite so it's a map of the geographic region so euro, North America, Africa at least
Africa wherever Asia I guess and in there you'll see like contour rings and in these particular rings
it'll tell you where you are where you are and what you need calculate out where
how what your azimuth is elevation and that sort of thing depending on where you are
and you can go to the website and they will have like documents showing all of this
and then you adjust your azimuth which is you find out where
South is which is the opposite of North and then you move the iridesh either east or west
depending on which way you want to go and then you pick the satellites and then you adjust
the azimuth which are the elevation which is open down and then you adjust the
the skew of the enemy I have no idea if I've said this before because I've already said
three times before anyway so I don't intend to use the satellite finder so much because it's
it's an analog device and it doesn't really tell you a lot of information it is also quite
difficult depending on the satellite you're trying to tune to if you the one that we were using
was next in the slot to the east of the astrosatellites so they to a to c to d and to f although
two a has been decommissioned and two g's up there now replacing us and 28.2 east and it was a very
difficult to to point that because you were blasted with each of these satellites and all their
signals coming down so they astroco located all their satellites in this Asian kilometer box
so that each of them transmitted at different frequencies in that area so from the point of view
of your dish it looked like one big transmission so you're switching physically from one satellite to
the next satellite to the next satellite to the next satellite but you didn't you don't have to move
your dish because they're all locations in that Asian kilometer block which sounds like a massive
space difference but you know what we're talking about you know three quarters two far away is this
we're talking about 20 30 nearly 40,000 kilometers away so yeah 18 kilometers in there is not
a lot and those it's not a perfectly circular core side that they those satellites have become
in and out 300 kilometers I think in the rotation of a day but that's by the by I'm I'm I know
completely you move in here again getting distracted getting distracted anyway yes dish
pointing so the actual easiest thing to do now when you want to point to a satellite dish is you get a
case it's reasonably cheap or you can get them secondhand and you go to satellite find your
website you put in a your town village latitude longitude where you are and that will bring up
a Google maps aerial photo and you can move the satellite icon to where you want to put your
satellite dish and then you select from the drop down list one of the satellites that you want to
and that'll give you all the lovely information down below so elevation in my case I need to be
26.5 degrees from from the horizontal azimuth true is 151.7 so if a new exactly where south was
and azimuth magnetic says 150.9 so when I go with a compass that's the hunky-dory so that would be
nice information as well but the other thing they do is draw a line over of the Google maps thing
and this line happens to intersect the hotel sign that's down at the train station so all I've
had to do has been hold on to the edge of the satellite dish and move it left and right left and
right until I find that it's more or less pointing at that thing now one cool thing about the
so I'm not using the satellite finder what I'm doing is putting it into the setup box receiver
which was connected to a portable TV and most of these devices setup box receivers have got a
have got a satellite finding mode where they'll give you the power and signal quality and my one
actually is able to name the satellite that you're pointing to which is actually awesome because
that tells you whoops well I'm say I'm pointing at asterisk to whatever and I want to point to
another satellite well there are three slots to the west to that so let's move at least I'm too much
left rather than too much right to get the idea so once you've that done first thing you should do
is try and find the azimuth if you can get that done your hunky-dory because you know the northern
south of that you're not going to be any other satellites it's just east and west the satellites are
located so yes so try and get that and if your device is able to tell you which satellite you're
locked onto you're absolutely golden and the satellite dish itself is connected to the mount so in
my case they it's a stand as I said with some concrete garden tiles holds on the down on a flat roof
point south so once you get that I guess there's like logclips that hold on the clamp so once the
clamp is fixed the clamp pulls on to the satellite dish and it's curved and the curve goal it's got
a curved mill groove that goes into a female groove on the back of the satellite dish and that's got
basically like a compass and it's in there got the degrees of elevation so that allows you to
roughly guess where the elevation is and in my case the numbers print on that bear absolutely
no resemblance to what it says here on this document 26.5 degrees and the thing actually says 19
degrees so well done there but that's where your satellite finder display power display will help
power and signal quality because once you get that right you know it doesn't actually matter if
you've got the wherever you happen to get the highest amount of signal strength you're absolutely
golden I remember trying to point a satellite dish for a demo and during the demos completely
blocked we could not see south and then one of the guys had a smart idea well let's point to the
building in the north which was a modern glass building and there's no satellite signal was
been rebounded off that building that we could point our satellite dish more or less north and still
be able to pick up a reception it was an absolutely awesome demo so you got your thingy you got
your elevation and now the only thing that you need to do is work out on skew so that is again
don't really look too much at the numbers look at the output from your satellite receiver and
just move it horizontally so if you were pointing the satellite dish if the satellite was like
directly south your skew would be zero but the more east and west that your satellite goes then
you need to adjust the skew to adjust for what would be horizontal in pointing at that satellite
now the reason to do this I don't know if I said this before but if I did anyway
the reason for that is that you to increase the bandwidth they send a horizontal and vertical
polarization so when this was explained to me at ham radio school ham radio class is actually
it's a rotation signal that comes through in the polarization but what actually means is that
one of the signals can be kept fairly well apart from the other signals so you can basically
double your satellite capacity okay once that is done what I suggest you do is tighten everything up
keep an eye on your signal because as you're tightening it up do like a drummer a good drummer
adjust the opposite sides equally so one turn on the left one turn on the right one turn on the left
one turn on the right that will keep it nice and tight and in tune and not moving around keep an eye
on your satellite settings and that you're getting maximum power maximum signal signal strength
I advise not to do this if you're working on a high building like I am when there's a lot of wind going
on although it seems to have quite a down again and keep an eye on your signal tighten everything
up and then one last tip is always make sure to just just as I said that it's big gust of wind
coming nearly no no no the off I'm going to just get a piece of a nail or something and just
scrape in the lines on your on your setup because that way then you're not going to
on your setups that if anything moves like this wind basically moves the satellite dish out
of the way that you'll be able to readjust everything rather quickly now just so that is pretty
much that now before I go down I'm just going to go over here and share out some leaves
I'm sleepy
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