Document text
FM Satellite
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FM SATELLITE
COMMUNICATIONS FOR
BEGINNERS
SHOOT FOR THE SKY... ON A BUDGET
BRIAN SCHELL
Copyright 2018 by Brian Schell.
All rights reserved, including the right to reproduce this book or any
portion of it in any form.
Written and designed by:
Brian Schell
[email protected]
Version Date: September 5, 2018
ISBN: 9781720105855
Printed in the United States of America
CONTENTS
Introduction
Why Do This?
Equipment
The Process
Other Software Tools
Using Common FM Satellites
Preparation Checklist
Tips
Next Steps: SSB and Linear Transponders
Links and Further Reading
About the Author
Stay Up To Date!
Help Me!
Also by Brian Schell
INTRODUCTION
Sputnik launched in 1957. Earth's first artificial satellite was a
milestone for humanity, and it orbited the Earth for three
entire weeks before its batteries died, and it burned up as it
fell back to Earth. Modern satellites have improved a bit
since then in longevity, power, and price. Rather than
requiring a "space race" and the resources of nations, satel-
lites and other payloads are launched on a regular basis,
many of which are communications related.
Still, for most people, the workings of satellites are a little
mysterious, and they're often the source of unfounded para-
noia. What do they do up there? Are they watching us? Can
they fall on my house? Even today, these kinds of questions
are still too common, as the masses direct suspicion at the
mysterious government agencies and powerful corporations
who control most of the satellites.
Many of us can remember, "back in the day," that many news
broadcasts had the subtitle "Live via satellite" below the
foreign correspondents. This was somewhat after "Now in
COLOR" stopped being a thing. There was a time when
V1 Introduction
satellite TV was a novelty that required a six- or eight-foot
dish and cost so much that only the TV stations could afford
to have them. Now, small "Dish TV" antennas are literally
everywhere, and in many cases are cheaper to use than
running a cable.
Nearly everyone has used GPS in some fashion or watched
satellite TV. Yet satellite technology still feels like a new and
complicated thing, literally out of reach for most people.
And using a satellite directly? Other than NASA experts and
“rocket scientists,” who does that?
Amateur radio enthusiasts do it, that's who!
OSCAR 1, the first amateur satellite, was launched way back
in 1961, just four years after Sputnik. Now, there are
numerous radio-equipped satellites in orbit that cater
specifically to hams. They're free to use, and the equipment
required is easy to obtain and set up. The historically difh-
cult part of the operation is knowing where the satellites are
(where to point the antenna), and that's easily solved today
with a simple web search or a smartphone app.
There are varying levels of difficulty in working with satel-
lites. Some are easy contacts, others are harder to hit. Some-
times you can reach a destination thousands of miles away,
sometimes you can talk to an astronaut on the ISS. There
are as many goals and projects in the satellite segment of the
hobby as there are with any other "Ham subculture."
Let's see how this all works.
WHY DO THIS?
The purpose here is much the same as any other facet of
amateur radio: to get more from technology, to communi-
cate with other amateurs, and because it's a fun challenge.
There are sometimes situations where there is no HF radio
available, or conditions are unsuitable for HF use, and long-
distance calls are desired. With a satellite setup, you can use
a simple and inexpensive handheld radio to talk to very
distant stations.
The basic idea of what we're going to do is this: Use a radio
and a directional antenna to receive and transmit signals to
and from orbital satellites. There’s a ton of science and
history behind all this, but we’re going to focus specifically
on the what-you-need-to-know details of how to do this.
Learning the history and science of satellites is for your own
research.
These satellites, in turn, do different things. Some simply
transmit beacons. Others contain transponders and digi-
peaters that will relay your communications to other
amateurs on the ground. The most common activity is using
2 BRIAN SCHELL
a satellite as transponder: Your signal goes into space, hits
the satellite, then gets retransmitted down to someone else
on the ground, just like a repeater in space. The most
popular ham satellites are “cubesats” or small 10-centimeter
cubes that are essentially repeaters in space.
That said, it's not all about just talking to other people on
the ground. You can also use the same technology to talk to
astronauts aboard the International Space Station, and even
download SSTV images from the space station as well. No
matter where your radio interests lie, there are a large
number of options available in the satellite portion of the
hobby that may appeal to you.
EQUIPMENT
Talking to or through a satellite sounds like it ought to be a
really expensive thing to do, but it's really a lot simpler than
you might think at first. Only a few things are required, and
many of those can be built or improvised.
Radio
It might seem obvious that you're going to need a radio, but
there are some specific things to be aware of.
Most satellites use two different frequencies. It's very
common for a satellite to transmit on the 2m band and
receive on the 70cm band (or vice versa), so you will defi-
nitely need either a dual-band radio or two single-band
radios. Satellite communications are very low-power, so
handheld (HT) radios are perfectly adequate to the job.
Moreover, they are a lot more portable than a mobile radio.
Still, if a mobile is what you have, you can use that well
enough too. Once you have mastered the FM satellites, you
may want to move up the difficulty scale to SSB transmis-
4 BRIAN SCHELL
sions through linear transponders, and that in turn necessi-
tates more complex equipment.
It's not strictly necessary, but it's nice if your radio is "full
duplex," meaning it is capable of transmitting and receiving
at the same time. Most handheld radios are not full duplex,
but that's not a deal breaker. The difference is that with full
duplex, you can hear yourself being transmitted through the
satellite, so it’s a great way to know everything is actually
working; there are a lot of variables, and just being confi-
dent that youre actually hitting the satellite makes your job
a lot easier.
If you aren't planning on talking (just listening), you can use
any scanner that allows you to tune into the receive
frequency. You'll just set the scanner frequency to whatever
the satellite transmits on, plug in the antenna, and aim in
the proper direction at the correct time. You don't even need
to be a licensed amateur radio operator to just listen. Doing
it that way is only half the fun, but it works!
Antenna
It's completely possible to talk to a satellite using the rubber
duck antenna on your HT radio; people do it all the time.
On the other hand, it's not really something you can depend
on, and getting through is more of a matter of luck and
having the weather conditions be just right than any real
skill. You'll do much better with an antenna designed
for this.
Most satellite folks swear by small Yagi antennas, and the
two most popular varieties are the Arrow II and Elk anten-
nas. People have been arguing back and forth over which
FM Satellite Communications for Beginners 5
model is better for decades, and there's no clear winner. |
have an Arrow II (see the cover of the book— that’s me and
my Arrow), and that works great for me, but others swear on
their Elk. They're roughly the same price ($150-ish), so
although they aren't cheap, this is really the only purchase
most hams need to make to get into this area of the hobby.
One interesting complication with this is that since satellites
work on two bands at once as mentioned above, you
transmit on 2m and receive on 70cm. And this requires a
dual-band radio or two single-band radios. In order to use a
dual-band radio, the antenna needs a diplexer to allow one
radio to control both bands with a single antenna jack.
I'm not much of a do-it-yourselfer, but it's not especially
difficult to make your own directional antenna. Just Google
"ham radio satellite antenna plans" and there are dozens of
links to show you how. I recently watched a YouTube video
called "$4.00 Ham Radio Satellite Antenna" where he makes
one from a stick and some wire coat hangers. I’ve seen more
than one article online about making one from an old tape
measure. There's a link in the "Links and Further Reading"
section towards the end of the book. I'm sure it's not going to
be as efficient as a purchased antenna, but it looks like a fun
project.
Other Items
The radio and antenna are the only absolutely required
items to do this, but a few other things will make your life
easier and make satellite work a lot more comfortable
and fun.
e A Watch or accurate timer. To be super-accurate,
BRIAN SCHELL
use a phone that can check time online. One
iPhone app that I've used for years is Emerald
Time. It uses Network Time Protocol to display the
current time of day as defined by the international
standard atomic clocks. Its accuracy is limited only
by network latency and is usually accurate to less
than +/-100 milliseconds. You really don't need
anything close to that kind of accuracy for this kind
of work, but... why not have it?
A Flashlight. You can obviously do satellite work
during the day, but it’s a lot of fun to go out at night
and try to visually spot satellites. Be prepared for
darkness. Note: You can’t actually see any of the
ham radio satellites as they are too small, but there
are hundreds of others that you can spot.
A Compass. You can "get by" with just knowing
which way is North, but since most listings will give
you very specific compass directions, it's good to
know exactly where to face. You can buy an
inexpensive "Boy Scout"-style compass easily
enough, but don't forget many smartphones have a
perfectly good compass app on them.
Headphones. Many satellite signals are very weak,
and depending on where you're working, external
noises can be quite high. Even in the so-called
"quiet countryside," wind and other natural noises
can often be a lot louder than you expect.
Handheld microphone. This is more of a
convenience than a necessity, but if you're holding
the antenna in one hand it's often less of a hassle to
use a handheld microphone rather than deal with
orienting and finding the transmit button ona
handheld radio. If you're using a mobile radio
FM Satellite Communications for Beginners ‘|
rather than a handheld variety, then this isn't even
optional.
e Recorder. Most people hold the antenna in one
hand and the microphone in the other. How are
you going to write down callsigns, times, and other
notes? You can't write them down, so a simple voice
recorder is a really helpful device. Again, a cheap
device is fine, and again, a smartphone voice-
recorder app could be all you need.
e Tripod. For improved aiming accuracy and to ease
arm strain, a tripod with some form of clamp to
hold your antenna is going to make your life easier.
This may not be the best way to get started (you can
actually learn a lot by flailing your antenna about
in the beginning), but once you've made a few
contacts, this is something to try. I've even seen
some hams make brackets to hold both the antenna
and the radio. They have gotten to the at of
almost being hands-free.
e Computer, Tablet, or Phone. In the previous
section, I mentioned using smartphone apps fora
compass, voice recorder, timer, and so forth, but the
most important use is for looking up where the
satellite is going to be at a specific time. This can all
be done ahead of time at home, and it's probably
best to look ahead and find out what time satellite
X is going to be in a good position.
Again, if you're in a hurry, or have to get by on a small
budget, most of the accessories above can be skipped or
built/bought at a later date if you need. If you already have a
smartphone, many of the tools can be replaced with the
proper apps.
ee
THE PROCESS
Research What You Can Do
This method works on any device that can access the web.
We'll talk about platform-specific apps and software later,
but for now, let's use what's freely available on websites.
Using Web Tools
With any satellite tracking tool, first you'll need to know
either your precise latitude and longitude, or more easily,
your grid square. If you don't know your grid square, you
can find it here:
http://www.levinecentral.com/ham/grid_square.php
Once you have that, go to the AMSAT page at:
http://www.amsat.org/track/
IO BRIAN SCHELL
AMBAT Online Satellite Pass Predictions
NOTICE: Fox 18 is now AO-91
Please select a satellite and provide your latitude, longitude and «lavation ar calculate them from your
gud square. if yau chause we vill save your position information in a cookie on you?
system for fiubure pradictinns.
Calculate Latitude and Longitude
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Athens Senne es eta keener UE)
Enter Decimal Lacinds
Amsat Start
In my case, I know my grid square is en83da, so I can plug
that in and it will figure out my latitude and longitude. If
you know your elevation above sea level, put that in too, but
it's not crucial.
Last, look the options in the drop-down box for "Show
predictions for" which defaults to showing "ISS." You can
choose from roughly two hundred different satellites now.
Let's say we want to try to hit the AO-85 satellite. Simply
choose "AO-85" from the list, check one more time to make
sure your location is as accurate as possible, then hit the
"Predict" button. It'll come back showing a table that looks
something like this:
FM Satellite Communications for Beginners II
AMSAT Online Satellite Pass Predictions - AO-85
View the current location of AO-85
AOS | Maximum: Max El LOS.
Azimuth | Elevation : Azimuth | Azimuth
5
LOS (UTC) |
00:11:55 167
Your results are shown above
Use the form below to request more pass predictions
Amsat Result
Now it's time for a couple of definitions.
AOS stands for Acquisition of Signal (or Satellite). AOS is
the time that a satellite rises above the horizon of an
observer.
LOS stands for Loss of Signal (or Satellite). LOS is the time
that a satellite passes below the observer's horizon.
UTC is Coordinated Universal Time. It's a standard time
zone that can be used anywhere. If you aren't sure what time
it is in UTC, check here:
https://www.timeanddate.com/worldclock/timezone/utc
AZIMUTH is the direction you need to face. Start out by
12 BRIAN SCHELL
facing north. North is "zero" degrees. Now turn to the right
(Eastward) until you have gone the specified number of
degrees. If you need 90 degrees azimuth, you'll turn to face
due East; 270 degrees would have you facing West. This is
where a compass might come in handy.
ELEVATION is the height off the ground that you need to
raise your eyes. Zero degrees elevation is looking at the flat
horizon. Ninety degrees Elevation is straight up. If, for some
reason, you have a negative elevation, that means the target
is below the horizon. It may or may not be obvious, but a
satellite has to be above the horizon for you to be able to
access it.
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Altitude and Azimuth [source:
http://commons.wikimedia.org/wiki/File:Azimut_altitude.svg]
FM Satellite Communications for Beginners 13
Now an example using the first line from the Amsat table
from a few pages back:
As I'm writing this section, it is July 11th, so if I go outside at
17:40 UTC time, then turn to 138 degrees azimuth at the
horizon (the actual horizon, not the tree line!), I'll be looking
right at AO-85. Over the next 8 minutes and 13 seconds, it
will drift to azimuth 64 degrees with the highest point being
at 112 degrees azimuth and 5 degrees elevation. If you aren't
confident in your ability to judge the elevation angles, pick
up a cheap protractor at an office supply store and use that
to help visualize the positions.
Be aware, that just because a bird shows up on the chart,
that doesn't guarantee you'll have a good chance of hitting it.
In the example above, 5 degrees elevation way is too low to
be practical in reality, but that's the first line on the chart.
In a real-world case where I wanted to actually HIT the AO-
85, I'd probably try to use the information from the second
line, where the maximum elevation is 57 degrees. At 19:17, I
would face 201 degrees azimuth (somewhat south-south-
west) and face the horizon. I would be aware that over the
next 14 minutes and 1 second that the satellite would drift
upwards to a peak at 57 degrees height around azimuth 118,
then head back down toward the horizon at 64 azimuth. I'd
expect to lose signal completely right around 19:31. Due to
the higher altitude and longer time above the horizon, this
satellite has a much better chance of being hit successfully
than the first example.
If I was patient and wanted the best chance of hitting the
bird, the 7th line has the maximum elevation and the
longest duration, so that would be the pass I'd look at first.
14 BRIAN SCHELL
Of course, depending on the location and any obstacles that
might be in the way in a certain direction, there are other
factors to take into consideration. Planning is key to success
in this.
Sigh. That's a lot of degrees and numbers. It's obviously best
to scout out the location ahead of time, get there a little
early, and look for landmarks near the start, end, and
midpoints of the sat's route.
Side note: For a “just for fun” activity at night sometime,
make a list of satellite passes during the time you'll be in a
dark place, then see how many you can actually spot visu-
ally. There are a lot more satellites that are visible than are
available for ham radio use, so you can stay pretty busy
identifying all the bright lights that pass overhead. Some
people make a hobby just out of visual sightings of satellites;
check out the site https://heavens-above.com/main.aspx
But we aren't done yet. You'll also need to know the frequen-
cies (plural) of whatever satellite you want to contact. The
most commonly used ham satellites that cover the USA (as
of mid-2018) are the SO-50, AO-85, AO-g1, and AO-g2, but
there are some other options for those outside the USA, and
several new satellites are scheduled for launch later in 2018.
A quick Google search can tell you updated information,
but Amsat.org will have the information on the most
common satellites.
https://www.amsat.org/fm-satellite-frequency-summary/
And you'll get a long listing that looks something like this:
FM Satellite Communications for Beginners 15
FM Satellite Frequency Su
mary
AMSAT Pox-} Satellites
Uplink FM
ue Downlink Fig Comments
{87 Hz CYCSS}
Satellite Frequencies and details
So let's look at AO-85 for an example. According to the
website, it has an uplink frequency of 435.170 and a down-
link of 145.980.
Uplink is the frequency you transmit on.
Downlink is the frequency you listen on.
The practical problem now becomes how do you transmit
on one band and listen on another? There are two common
approaches. First, you can use two handheld radios, one for
listening, and one for transmitting. There's nothing at all
inherently wrong with this approach, but it's more hardware
to deal with and just one more thing to mess up. Two radios
also means more cabling and more physical "stuff" to
arrange and find a place for. The second approach, and the
one that most hams use, is to use a single dual-VFO hand-
held radio with VFO A set to the uplink frequency, and VFO
B set to the downlink frequency.
16 BRIAN SCHELL
Note also if the satellite you want to use requires a PL tone
or a special "wakeup" tone. Some do, some don't.
Compensating for the Doppler Effect
Now the part that gets tricky. You will be standing still, so
your position isn't going to change on Earth. The satellite,
on the other hand, is moving through space at an incredible
speed relative to you. You've heard the change of pitch a fast
car makes as it passes while you stand near the road? That's
called the "Doppler Effect," and it can have a huge effect on
radio frequencies.
The uplink (your transmitting) frequency in the chart for
AO-85 is 435.170. This is the actual frequency the bird uses,
but due to its high velocity, the number is going to change as
it passes because of the Doppler shift. The best way to deal
with this is to initially set the frequency a little below the
listed frequency to start, and adjust it upwards as it passes
over. To save confusion later, many hams will program the
frequencies into their radio ahead of time. Of course, the
frequencies listed below are only for the AO-85 satellite;
each satellite will have a different sequence of frequencies:
435.160 (start listening here, a little bit below the
listed frequency)
435.105
435.170 (the actual frequency listed on the chart)
435.175
435.180 (probably won't get above this, but it
might get that far)
So you start transmitting at the lowest frequency on the list,
FM Satellite Communications for Beginners 17
and as the bird passes overhead, you turn to the next
frequency on the list, and so forth. Depending on the length
of time the satellite is above the horizon, the amount of
"doppler drift" could be significant. If the satellite is coming
straight toward you, more or less right overhead, then you
may need all these frequencies; if it's moving at a low angle,
then all five frequencies probably won't be needed.
Compensating for Doppler Shift is an acquired skill, and
you'll need practice to be able to do it correctly.
After you've done this a bit, and have made contacts on a
few different satellites, you may want to program your radio
with a "bank" of satellite frequency ranges that you've used.
As a rule of thumb, program frequencies +3.5 kHz for 2m
frequencies and +10 kHz for 70cm frequencies. There are a
number of completed example programming setups shown
later in the book.
Now here’s another tricky bit. You only need to do these
adjustments on the 70cm band (that is, the higher frequency
band). It doesn’t matter which band is the uplink or which is
the downlink, but the 70cm band always gets the adjust-
ments. The Doppler shift on the 2m band is little enough
that you can disregard it.
In the example above, the uplink frequency was 435.170, so
we programmed a sequence of uplink frequencies above
and below it. On the other hand, if we were programming
for the SO-50 satellite, for example, its downlink is 436.795,
and so that’s the number we need to adjust for Doppler
Shift. It's easy to remember that the higher frequency band
numbers are always the ones to need adjustments.
Thought that was complex? Here’s one more thing: Uplink
18 BRIAN SCHELL
frequencies get adjusted upwards during communica-
tions, while downlink frequencies get adjusted down-
wards. If we can use that moving car analogy again, you
know that if you are listening to a fast car drive by, you can
hear the pitch change as it approaches. It’s the trickiest part
of the whole project, but we’ll go over some very specific
programming examples when we start to discuss the
common satellites later.
Doppler Shift Summary:
e The frequency in the 70cm band needs to be
adjusted during the satellite pass.
e Uplink frequencies get adjusted upwards
e Downlink frequencies get adjusted downwards.
e Only one 2m frequency is needed. These don’t need
steps, as Doppler shift on 2m is negligible.
Polarity
You have probably seen a photo of a satellite in space, but a
still photo makes a satellite look a lot more stable than it
really is. These little cubesats tumble and roll around a lot,
so “this end up” isn’t really a thing in orbit. Those little
antennas are rotating as well, and this sometimes causes
issues with polarity. There’s no way to predict or completely
eliminate this problem, but if you have a handheld antenna,
try rotating it and twisting it in your hand until you find the
strongest signal.
Squelch
If you haven't figured it out yet, satellite communication is
FM Satellite Communications for Beginners 19
very hit-or-miss, with a lot of very weak signals and noise.
It's best to turn your radio’s squelch completely off and
listen through the static rather than try to eliminate it. Many
satellite transmissions are weak enough that they won't
make it through even a low squelch setting.
OTHER SOFTWARE TOOLS
iOS Tools
For the iPhone and iPad, I recommend the HamSat HD,
ProSat HD, and ISSHD apps, all created by Craig Vosburgh.
All three work in similar ways, to read in your location data
and tell you in several different ways what you can access
and when. My favorite mode is a 3D globe of the Earth with
various satellites shown above it, including different colored
circles around each one displaying the radius where it
should be accessible; if your map location is within the
circle, you might want to give it a try.
All these satellites and circles move and update in real time,
so if you move too slowly, you'll be able to see that visually
as well. If you click on a specific satellite, you can see the
latitude and longitude of the satellite's current location as
well as the azimuth and altitude for your own location. The
three apps work very similarly to each other, and none
are free. |
As of this writing, the ISS Edition is $2.99, the HD edition is
22 BRIAN SCHEEL
$7.99, and the Pro HD edition is $9.99; they are nice-looking
but also don't offer anything you can't find on the AMSAT
websites. It’s just a lot more visual, which my or may not be
worth it for you. The ISS edition includes only the
International Space Station, while the other two are more
for communications satellites, with the main difference
being that the PRO version has more satellites (and prob-
ably weaker contacts). There are other satellite tracking
programs in the App Store, but most of them aren't really
oriented toward amateur radio.
O8 3
Rs sty. 39,2
Location instersnation: is Et Debi 2REe
A Me... Rome a KS ae Lar BAS dep
HamSat HD
iPhone Tools
The three apps listed above for iPad are also available for
the iPhone. They're universal apps, so if you purchase the
app for one device, it'll work on the other, so that's good for
FM Satellite Communications for Beginners 23
planning at home on your big-screen iPad and to carry with
you on your iPhone. :
Android Tools
Tythatguy has an excellent tracking app called surprisingly
"Satellite Tracker" and RunaR has a good one for just the ISS
called "ISS Detector Satellite Tracker."
"Satellite Tracker"
24 BRIAN SCHELL
"ISS Detector Satellite Tracker"
Windows, Mac, and Linux Tools
My own preference is to use a mobile app like one of the
ones already described or the free, web-based apps available
on the AMSAT page. Still, there are some very advanced
software tools available. Check out the latest releases at the
AMSAT page before continuing:
http://www.amsat.org/amsat-new/tools/software.php
Here are some screenshots of the best-looking ones:
FM Satellite Communications for Beginners 25
705 445952. 734
06:29:09 UTC:
06:38:09 UTC:
10:36:18:
00:09:00:
189°:
12°:
75°:
13
0.0"
60.7:
Sun
20,787:
Nova Software for Windows
26
BRIAN SCHELL
MacDoppler for Mac
USING COMMON FM SATELLITES
There are an uncountable number of satellites in orbit, but
only a handful use frequencies that are within the ham
bands, and only a few of them are usable with FM. Here are
the "usual suspects" for users in North America:
Common Satellite Uplinks and Downlinks
67 Hz
(74.4 wakeup)
The above is quick reference, check out current information
before programming your radio:
28 BRIAN SCHELL
https://www.amsat.org/two-way-satellites/
Some of these satellites require more in the way of program-
ming considerations. For example, SO-50 has the same 67Hz
PL tone as several of the others, but has a “sleep timer” that
puts the satellite to sleep after ten minutes. You'll need to
“wake it up” by transmitting a 74.4 Hz tone for two seconds
before calling CQ. Having TWO PL tones is unusual in that
you will need to program two channels into your radio; one
for the wake-up call, and one for the transmit frequency.
Other weirdness, such as the LilacSat-2 only being available
three days a week, and IO-86 only being accessible from
equatorial regions, also must be taken into consideration.
Whichever bird you want to use, do some research on the
AMSAT site to make sure you have all your bases covered.
Some Notable Hamsats
OSCAR 1 (No longer in service)
The first amateur satellite, simply named OSCAR 1, was
launched on December 12, 1961, barely four years after the
launch of world's first satellite, Sputnik I. The beginning of
this project was very humble. The satellite had to be built in
a very specific shape and weight, so it could be used in place
of one of the weights necessary for balancing the payload in
the rocket stage. OSCAR 1 was the first satellite to be ejected
as a secondary payload (with Discoverer 36 as the primary)
and subsequently enter a separate orbit. The satellite
carried no on-board propulsion and the orbit decayed
quickly. Despite being in orbit for only 22 days, OSCAR 1
was an immediate success with over 570 amateur radio oper-
FM Satellite Communications for Beginners 29
ators in 28 countries forwarding observations to Project
OSCAR.
OSCAR-1 The first Hamsat
The following descriptions are paraphrased from Amsat.org:
AO-85 (Operational)
Fox-1A, AO-85 or AMSAT OSCAR 85 is an American
amateur radio satellite. It is a 1U Cubesat, was built by the
AMSAT-NA and carries a single-channel transponder for
FM radio. The satellite has one rod antenna each for the 70
centimeter and 2 meter bands. To enable a satellite launch
under NASA's Educational Launch of Nanosatellites
(ELaNa) program, the satellite continues to carry a Penn
State University student experiment (MEMS gyroscope).
30 BRIAN SCHELL
The satellite was launched on 8 October 2015 with an Atlas
V rocket together with the main payload, Intruder 1A (also
known as NOSS-3 7A, USA 264 and NROL 55) and 12 other
Cubesat satellites (SNaP-3 ALICE, SNaP-3 EDDIE, SNaP-3
JIMI, LMRSTSat, SINOD-D 1, SINOD-D 3, AeroCube 5C,
OCSD A, ARC 1, BisonSat, PropCube 1 and PropCube 3)
from Vandenberg Air Force Base, California, United States.
After just a few hours, the transponder was put into opera-
tion, initial connections were made between amateur radio
stations and telemetry was received.
AO-91 (Operational)
Fox-1B, AO-91 or AMSAT OSCAR g1 is an American
amateur radio satellite. It is a 1U Cubesat, was built by the
AMSAT-NA and carries a single-channel transponder for
FM radio. The satellite has one rod antenna each for the 70
centimeter and 2 meter bands. Fox-1B is the second amateur
radio satellite of the Fox series of AMSAT North America.
AO-92 (Operational)
Fox-1ID, AO-92 or AMSAT OSCAR 92 is an American
amateur radio satellite. Fox-1D is a 1U CubeSat developed
and built by AMSAT-NA. Fox-1D carries a single-channel
transponder for mode U/V in FM. Fox-1D has an L-band
converter (the AMSAT L-band downshifter experiment),
which allows the FM transponder to be switched on an
uplink in the 23 centimeter band.
FM Satellite Communications for Beginners 31
SO-50 Satellite
SO-50 (Operational)
SO-50 carries several experiments, including a mode J FM
amateur repeater experiment operating on 145.850 MHz
uplink and 436.795 MHz downlink. The repeater is available
to amateurs worldwide as power permits, using a 67.0 Hertz
PL tone on the uplink, for on-demand activation. SO-50 also
has a 10 minute timer that must be armed before use.
Transmit a 2 second carrier with a PL tone of 74.4 to arm
the timer.
32 BRIAN SCHELL
The repeater consists of a miniature VHF receiver with
sensitivity of -124dBm, having an IF bandwidth of 15 KHz.
The receive antenna is a 1/4 wave vertical mounted in the top
corner of the spacecraft. The receive audio is filtered and
conditioned then gated in the control electronics prior to
feeding it to the 230mW UHF transmitter. The downlink
antenna is a I/4 wave mounted in the bottom corner of the
spacecraft and canted at 45 degrees inward.
LilacSat-2 (Operational)
The LilacSat-2 FM repeater is currently planned to be active
for 24 hours at a time, starting around 2200 UTC on
Mondays, Wednesdays, and Fridays. This schedule is flexi-
ble, and subject to change without prior notice.
As with other satellites, full-duplex operation is preferred.
This allows you to hear your own signals from the satellite,
without relying on others to confirm that. Please listen
around the 144.350 MHz uplink frequency before working
LilacSat-2 passes, as this is a frequency outside the normal
2m amateur satellite sub band at 145.800-146.000 MHz. The
144.350 MHz uplink frequency is a legal uplink frequency
per the International Radio Regulations and (in the USA)
FCC Part 97, but may conflict with local or regional
band plans.
Specific Programming Examples
Back when we first discussed Doppler Shift, 1 mentioned it
was complicated. Let’s make it simpler. Here are some
specific programming tables incorporating doppler adjust-
FM Satellite Communications for Beginners 33
ments for four of the most common satellites as well as the
ISS. These are actual examples as I have them entered in
the CHIRP programming software. If you aren't familiar
with CHIRP, check my book on the free software in the
“Also By” section. Otherwise, these tables are easily adapted
to any other amateur radio programming software:
Acquisition of Signal
s000 Approaching
AO-85 MAIN
ng ee ae
Loss of Signal
| ABS Downiink
AO-85 Programming in CHIRP
As you can see in this first listing, the downlink is at 145.98
mHz (memory channel 26 in this listing), and that’s all you
need for the 2m band. The “main” uplink frequency is 435.17,
and I’ve programmed two small steps above and below that
frequency (memories 20-24). Also, I’ve included the neces-
sary PL Tone of 67 Hz for all the uplinks to activate the
repeater.
In the field, I set my VFO-A to the Downlink frequency, and
VFO-B to the first of the uplink frequencies (435.16 in the
example). If youre using two single-band handheld radios
instead of a dual-band system, then program one radio for
the uplink frequencies and the other for the downlink.
If I then point the antenna in the right direction at the right
34 BRIAN SCHELL
time, I should eventually hear something. In this case, the
downlink doesn’t change, but the uplink will need to be
adjusted upwards as it passes from the point of acquisition
of signal to the place where the signal is lost. How much you
adjust it depends on how much of an angle the satellite is
traveling at in relation to you.
Always wait to make sure you can clearly hear the satellite
before you transmit to it. If it seems to be working, but no
one seems to hear you speaking, try adjusting to one of the
other uplink frequencies.
To program the radio for the AO-91 and AO-92 satellites, the
process is pretty similar:
-438.340000°
438,250000
| Loss of Signal
AO-92 Downlink
AO-92 Programming in CHIRP
FM Satellite Communications for Beginners 35
The SO-50 bird is a little bit of an oddball. The uplink is in
the 2m band, and the downlink is 70cm, so everything is a
little backwards. In this case, you don’t adjust the uplink;
instead, you listen for a weakening downlink signal, and
when the signal starts to fade, you adjust the downlink
frequency to the next step. The SO-50 also needs to have an
additional memory programmed because it has a special
“wake-up” PL tone that it needs to hear before it activates:
80-50 Uplink "Wake Up
_. 50 Uplink . Ol
{None}
Nore)”
SO-50 Programming in CHIRP
Lastly, here are some frequencies to get you started with
contacting the International Space Station. There’s no PL
tone for anything on the ISS, but depending on which ITU
region you are in, the uplink changes:
36 BRIAN SCHELL
-148.800000
ISS Programming in CHIRP
Where do I get all this information? It’s all on the Amsat.org
website. It’s just a matter of knowing what information you
need to prepare before grabbing your antenna.
Satellite Pass Predictions:
https://www.amsat.org/track/index.php
Current Satellite Status:
https://www.amsat.org/status/
Satellite Schedules:
https://www.amsat.org/satellite-schedules/
Specific Details on individual Satellites:
FM Satellite Communications for Beginners
https://www.amsat.org/two-way-satellites/
And
https://www.amsat.org/fm-satellite-frequency-summary/
37
ia ul
“
Dat Bee ienu it
PREPARATION CHECKLIST
Research
Before you do anything else, look up the information about
the satellites you want to try. From Amsat.org, you need:
1. AOS (acquisition of signal) time. Convert this in
your head to local time, and double-check this to
make sure you don’t arrive an hour too soon!
2. Compass direction for where the satellite will rise
over the horizon.
3. LOS (loss of signal) time.
4. Compass direction for where the satellite will
disappear over the horizon.
5. Maximum altitude of the satellite.
6. Frequency and PL code(s) to program into
your radio.
40 BRIAN SCHELL
Radio Preparation
1. Make sure squelch is turned off.
2. Program in uplink frequency.
3. Program in a range of doppler-adjusted downlink
frequencies (five frequencies usually will do it).
4. Set one band for the uplink, and the other on
whichever downlink frequency you are going to
start with.
5. Assemble the antenna.
6. Make sure you have any cables or batteries that you
may need.
7. Don't forget optional accessories like a compass,
recorder, notepad and pencil, flashlight, and
anything else that may come up.
On-Site Preparation
1. Look at your compass, and note landmarks where
the satellite will appear above the horizon.
2. Also note where it will sink below the horizon.
3. Where will the highest point of the path be.
4. Plug in the antenna to the radio and get your
hardware ready.
5. Acouple of minutes before the satellite is
scheduled to rise, turn on the radio and point the
antenna in the right direction, just above the
horizon.
6. Wait and listen. Rotate the antenna from time to
time; adjusting the polarity sometimes helps with
weak signals.
FM Satellite Communications for Beginners 41
7. Once you hear the bird coming through the
downlink, wait for an opening and call CQ, or
answer one if someone else is calling.
Logging Your Calls
For a lot of hams, building up the logbook is a big portion of
the fun. I wouldn't recommend taking along a computer
unless you have a table set up, but somehow you need to
keep a record of who you heard, who you talked to, and
what times things happened. Assuming you are working
alone, the best tool for this job is to simply record every-
thing and sort it out later. If you have someone else along
with you to help, this may be less necessary, but signals are
often weak enough that it may be hard to catch everything.
So even with a helper, a recording may be useful.
Once you get home and can get comfortable, fill up your log
with all those juicy contacts. While you are at it, be sure to
report to AMSAT what satellite you used and how well it
worked through their “status” page:
http://www.amsat.org/status/
TIPS
e If you cannot hear anything through the downlink,
do not try transmitting to the uplink. Just because
you can't hear the bird doesn't mean someone else
isn't using it. Transmitting when you can't hear a
response just ruins things for everyone.
e Don't overpower the satellite. Five or ten watts is all
this should take, and any more than that causes
problems - some sats even filter out signals that are
too strong.
e Another tip that could help if you have the
equipment for it: A device like the SDRplay that
can show an entire band visually on a computer
screen is extremely useful for fine-tuning your
antenna aim. It’s probably not necessary to get this
precise with tuning, as the birds are moving at high
speed and part of the fun is in “the chase” anyway,
but it’s something to think about if you have an
SDR device.
e There's not much time for a QSO, so work as
quickly and efficiently as possible. Just call CQ
44
BRIAN SCHELL
quickly with a"KD8OTD CQ KD8O0TD" to give
your call sign twice. Use the regular letters and
numbers, don't slow it down with phonetic
alphabet. Alternately, to call someone else (maybe
arranged ahead of time), give a quick "KA9SCF this
is K.D8OTD" Once you do make contact with
someone, give your name, grid square, and QTH. A
signal report is unnecessary-- you're hearing them,
so that's all that matters! The bottom line is that lots
of people want to make contacts, so hit them quick
and let go.
If you screw up and get something wrong, don't
worry about it. Stay relaxed and enjoy the hobby.
There's a lot of factors involved with satellite
communications, and you may not succeed on the
first try (or first few tries). People who start a QSO
often drop out for one reason or another.
Remember, it's as much a challenge for the guy on
the other end of the call as it is for you— Things
are going to fail.
It's not a requirement, but remember that a full-
duplex radio lets you verify that you are correcting
for Doppler Shift properly, that you are hitting the
satellite, you have enough power, and that nothing
else is wrong. If you can hear your own voice being
transmitted from a sat, you know you have
everything set correctly. If no one answers, you can
be reasonably confident that it's not due to your
mistake.
Don't get beat up or arrested. That sounds like a
joke, but it's not. I've heard more than one story of
some ham being accused of pointing their antenna
near someone's house and having the police called.
FM Satellite Communications for Beginners
It's not hard to explain to someone that you're not
"listening" to them, but only if they want to listen.
Common sense should make it obvious that those
"metal sticks" can't magically "hear" what's going on
in your house, but try explaining that to an irate,
drunken husband at midnight sometime. You
might have better luck explaining to the police, but
depending on the situation and timing, maybe not.
Pick your site carefully. Unless your neighbors all
know what you are doing, a small suburban
backyard might not be the best place to try any of
this. In my case, there's a large disc-golf course, a
former full-size golf course, a block from our house,
so I just go there and set up. I can point my Arrow
antenna any direction I need without worrying, and
it's a wide-open space offering plenty of visibility
for my own safety. Scout out a place in the daytime
before arriving for an after-dark flyover. It's
common sense, but enough hams get in trouble
over this to make it worth a mention. Even without
the risks of getting assaulted or arrested, there’s still
a matter of tripping or falling over something in the
darkness.
For some specialized digital modes, such as SSTV
from the IIS, you generally only receive a broadcast.
All you need to do once you've got your equipment
set up is to record the audio from the ISS and you
can run that through decoding software at home
later - it doesn’t need to be done in real time!
45
NEXT STEPS: SSB AND LINEAR
TRANSPONDERS
The purpose of this book is to get you up and running with
FM satellites, but most of the same basic concepts apply to
SSB transmissions as well. This section is here just to point
out that SSB and FM communications have some practical
differences.
Linear transponders are a step or two up in complexity, as
most transponder uplinks are in LSB mode and downlink in
USB mode, which completely changes the type of radio
you ll need. I’m not aware of any current HTs that do SSB, so
at the minimum, you'll need a dual-band radio that can do
2m and 70cm in SSB. Most mobile UHF/VHF radios can’t do
SSB either, so the choice of radio models is somewhat small.
Also, since this kind of setup often requires a table and
power supply, simply going out into a field with a handheld
radio is generally not an option. Folks who are into this
mode often stay home and use a computer-aimed antenna
on a tower. As you can guess, this is a big step up in cost
as well.
To make matters even muddier, Doppler shift is far more
48 BRIAN SCHELL
complicated with SSB. With FM radios, you can program
little steps and adjust the frequency that way, but SSB is so
narrow-band that smooth and continuous adjustments are
required. Most people who do this kind of work use
computer-controlled radios and maybe computer-aimed
antennas as well.
There are benefits to using this more complicated system.
Multiple users and conversations can take place simultane-
ously over the range of frequencies covered by these birds,
and they also can support CW, APRS, SSTV, PSK31, and
many other digital modes.
For a quick look at the satellites you can hit in this manner,
and the appropriate modes and frequencies, check out
https://www.amsat.org/linear-satellite-frequency-summary/
LINKS AND FURTHER READING
Know your grid square:
http://www.levinecentral.com/ham/grid_square.php
SSTV:
https://amsat-uk.org/beginners/iss-sstv/
AMSAT:
https://en.wikipedia.org/wiki/AMSAT
ARISS:
http://www.ariss.org
OSCARs:
https://en.wikipedia.org/wiki/Amateur_radio_satellite
Emerald Time iPhone Time App:
https://itunes.apple.com/us/app/emerald-
time/id290384375?mt=8
Arrow II 146/437-IOoWBP Antenna
50 BRIAN SCHELL
http://www.arrowantennas.com/arrowii/146-437.html
Elk 2M/440L5 Antenna
https://elkantennas.com/product/dual-band-2m440l5-log-
periodic-antenna/
$4.00 Ham Radio Satellite Antenna (Youtube Video)
https://www.youtube.com/watch?v=Hy_XwvMmlro
ISS Fan Club
http://issfanclub.com/
ISSTracker (no predictions, just live tracking)
http://www.isstracker.com/
A very good web based site for satellite prediction is:
http://www.heavens-above.com/
ABOUT THE AUTHOR
Brian Schell (KD8OTD) is a former College IT Instructor
who has an extensive background in computers dating back
to the 1980s. Currently, he writes on a wide array of topics
from computers, to world religions, to ham radio, and even
releases the occasional short horror tale.
He'd love to hear your stories of success and failure with FM
satellites and antennas. If there’s something you would like
to see in a future edition of the book, or otherwise have
suggestions, please drop him a note. Contact him at:
Web: http://BrianSchell.com
Email: [email protected]
wW twitter.com/BrianSchell
Ei facebook.com/Brian.Schell
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ALSO BY BRIAN SCHELL
Amateur Radio
« D-Star for Beginners
¢ Echolink for Beginners
¢ DMR for Beginners Using the Tytera MD-380
¢ SDR for Beginners with the SDRPlay
¢ OpenSpot for Beginners
¢ Programming Amateur Radios with CHIRP
¢ FM Satellite Communications for Beginners
Technology
¢ Going Chromebook: Living in the Cloud
¢ Going Text: Mastering the Power of the Command Line
¢ Going iPad: Ditching the Desktop
¢ DOS Today: Running Vintage MS-DOS Games and Apps ona
Modern Computer
Old-Time Radio Listener’s Guides
¢ OTR Listener’s Guide to Dark Fantasy
The Five-Minute Buddhist Series
e The Five-Minute Buddhist
e The Five-Minute Buddhist Returns
e The Five-Minute Buddhist Meditates
¢ The Five-Minute Buddhist’s Quick Start Guide to Buddhism
¢ Teaching and Learning in Japan: An English Teacher Abroad
Fiction with Kevin L. Knights:
¢ Tales to Make You Shiver
¢ Tales to Make You Shiver 2
¢ Random Acts of Cloning
e Jess and the Monsters
| | | | | ill | | Made in the USA
30844103R00041 San Bernardino, CA
31 March 2019
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Brian Schell lives in Flint, Michigan and is an author,
currently writing the “For Beginners” guides and “Tales
to Make You Shivers” series of books. He does editing
and audiobook narration when not busy writing. He’s
spent time in Japan, taught English abroad and in the
USA, and is an avid Amateur Radio operator (KD8OTD)
and all-around technology addict.
With an educational background in Religion Studies and
English Composition, as well as a long history of
Entrepreneurship and business management, he brings
an unusual perspective to most topics.
A practical, what-you-need-to-know guide to getting started making
amateur radio contacts via FM radios and satellites.
All that's required to begin is a good handheld radio, an inexpensive
antenna, and a smartphone. Of course, you can get complicated
(and expensive) in this area of the hobby, but we're going to keep it
to the basics here.
Inside you'll Find step-by-step tutorials on finding out where, when,
and how to connect to the various "Amsat" satellites that can be
accessed by amateur radio operators. The same information can be
used to look up hundreds of other non-ham satellites that you can
visually spot or listen to with a radio.
The sky has never been more accessible! This short book gives you a
simple step-by-step walkthrough of all the options to make long-
distance contacts through an inexpensive Yagi antenna using mostly
Free software available on the Internet and includes many
screenshots and examples. The whole process is detailed, from
buying (or making) an antenna to programming your radio and
adjusting for Doppler shift.
Once you know a few simple procedures, you can start making your
First calls to individuals, ham repeaters, or world-wide talk groups.
———