Transcript Slide 1

Phone – But Not Telephone!
In the radio world, phone
transmissions are voice
transmissions by radio. When
you hear hams use the word
“phone,” it usually has nothing
to do with telephones.
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Modulation
A transmitter produces RF energy –
radio waves – at a particular frequency.
But radio waves are not much use unless
they carry information. The process of
putting information onto a radio wave is
called “modulation.” Information can be
placed onto a radio wave in several
different ways. You don’t need to know a
lot about the different types of
modulation for the Technician exam, but
you do need to understand a little about
each one.
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Radio Wave Review
When you learned about
frequency, you saw that a radio
wave can be represented by a
sine wave like this:
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Radio Wave Review
You also saw that the distance between
a point on one wave and the same point on
the next wave represents the wavelength of
that wave.
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Radio Wave Review
The number of waves traveling past a single
point in one second represents the frequency of
the wave, as the following diagram shows.
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Amplitude
Before we can study the different kinds of
modulation, we have to look at one more
characteristic of a radio wave. The height from
the top of a wave to the bottom of that wave is
called the “amplitude” of the wave.
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Modulation
Again, modulation is the
process of placing information
onto a radio wave for
transmission.
Now we are ready to look at
some of the different ways a
radio wave may be modulated.
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Continuous Wave (CW)
Here is an ordinary radio wave. It is represented by
our old friend, the sine wave. If we cause a
transmitter to transmit a wave like this but do not
modulate the wave in any way, it would look something
like this. This is called a “continuous wave” or just
“CW.”
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How CW Is Used
Now take a look at this wave. Do you see the gaps?
If you turn the transmitter on and off, you leave gaps
in the wave. A properly-equipped receiver at the other
end will hear a tone when the CW is being transmitted
and nothing when the transmitter is switched off. This
is how Morse code is sent. In fact, hams often say they
are “working CW” instead of saying they are sending
Morse code.
Note that this represents the letter “K” or “dah-didah”.
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“Keying” the Transmitter
When we use a transmitter to
send out radio waves, whether
we are talking, sending Morse
code, or sending data, we say
that we are “keying” the
transmitter. This goes back to
the very early days of radio
when telegraph keys were used
to turn the transmitter on or
off as code was being sent.
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CW – Sending Code
Even today, when we use a telegraph key to
send code, all we are doing is using the key to
turn the transmitter on and off to form the “dits”
and “dahs.” (Hams don’t usually call them dots
and dashes.) When we press down on the key, the
transmitter is turned on and begins sending CW.
When we release the key, the transmitter stops
sending CW. As you can see, the transmitter is
turned on and off many times in a minute when
sending Morse code.
One big advantage of CW is that it has the
narrowest bandwidth of all the modes the
Technician uses. It is narrower than AM, FM, SSB
or slow-scan TV.
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Amplitude Modulation (AM)
We need to be able to do more than turn a
radio wave on and off to get a voice transmitted
over the airwaves. One way of doing that is to
use “amplitude modulation” or “AM.” To understand
AM, we need to do a little review and also get a
little more background information, so let’s do
it!
One other thing. This is going to get a
little complicated, so take it slow and easy.
Much of what you will see in the next few slides
is not essential for the test. However, it will
help you to better understand what is important
once you actually get on the air, and after all,
that’s what this test is really all about –
getting on the air!
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The Human Voice
You may remember that the
human voice has an average
range of about 300 to 3000
Hertz. Compared to radio
waves, the frequency of the
human voice is quite low.
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Generating a Voice Signal
Using the Microphone
When you speak into a microphone,
the energy from the sound waves made
by your voice is turned into an
electrical signal. This signal is
an electric current that constantly
changes with your voice. This
electric current can be represented
by a sine wave, just like a radio
wave. If it is a steady tone, it
will be a smooth sine wave that
looks just like a radio wave, except
its frequency will be much lower.
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Voice Waveform
But your voice is not a steady tone. The
sounds you make and the pitch or tone of your
voice is constantly changing. A sine waveform
that represents your voice might look something
like the picture below. This is the signal we
want to modulate the radio wave with.
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The Carrier
Now let’s suppose we have a radio wave
at a particular frequency that we want to
modulate with the signal in the last
slide. That will be our carrier and the
sine waveform for it will look something
like this:
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The Carrier and the Signal
To modulate the carrier, we have to
combine it with the electrical signal
representing a voice that was produced by
the microphone.
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So How Do We Do It?
This signal is applied to the radio wave so
that it causes the height or amplitude of the
radio wave to change as the signal changes. We
call this “amplitude modulation.” On our sine
wave it looks something like this:
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Let’s Look At All Three
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Amplitude Modulation
If you need to, go back to the
last slide and notice that the
signal representing the sound wave
caused the height or amplitude of
the radio wave to change as it
changed. This output is an
amplitude modulated signal. The
radio at the other end will extract
the signal from the radio wave and
feed it through the speaker at that
end so it can be heard.
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Sidebands
A modulated AM radio wave
also produces two other signals
called sidebands. One sideband
has a slightly higher frequency
than the carrier, and the other
has a slightly lower frequency.
It works something like this
this...
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Modulated Carrier and
Sidebands
Let’s say you have an audio tone that is 256 Hz. You
modulate a radio wave that is 710,000 Hz (710 kHz). You
produce an upper sideband that is 710,000 plus 256 Hz and a
lower sideband that is 710,000 minus 256 Hz. Keep these
sidebands in mind. They will become important in a little bit.
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AM – Not Used That Much
Amplitude modulation (AM)
used to be used by hams a lot,
but it isn’t used all that much
any more. The reason is that
the modulated wave and two
sidebands take up a lot of
“bandwidth.” You can only get
so many signals on a band, and
AM just uses too much space.
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Single Sideband (SSB)
The good news is we don’t need all of
that modulated AM signal. Each of the two
sidebands contains a complete copy of all
the voice information! If we strip away
the modulated wave and one of the
sidebands, we have a signal that is only a
third as wide. This is called “single
sideband” modulation or “SSB.” Because it
uses one of the sidebands of an amplitude
modulated signal, SSB is actually a very
efficient form of amplitude modulation.
Let’s take a look...
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First Start With The Full
AM Radio Wave...
This is the 710 kHz wave
modulated with a 256 Hz tone you saw
a few slides back.
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Now Filter The
Carrier...
We can get rid of the carrier,
and we are left with just the two
side bands, like this:
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Next, Get Rid Of One
Sideband...
We can also get rid of one of the
sidebands. It doesn’t matter which one,
but in this example, we’ll get rid of the
lower one.
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See How Much Space We
Save?
Before:
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After:
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Advantages of SSB
There are two advantages of SSB over
AM. First, we can put all of the
transmitter’s power into transmitting the
one sideband, so the effect is to make the
signal almost three times stronger. The
second advantage is that the approximate
bandwidth of a single-sideband voice
signal is between 2 and 3 kHz. This is
about one third of an AM signal. Because
the bandwidth is much narrower, more
people can use the same amount of band
space.
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Uses of Single Sideband
(SSB)
SSB is the type of voice
modulation most often used for long
distance and weak signal contacts on
the VHF and UHF bands by all amateur
license classes. The upper sideband
is normally used for VHF and UHF SSB
communications. SSB is also the
mode most often used by General
class licensees and higher on the HF
bands
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Frequency Modulation (FM)
Another way of placing information on a
radio wave is to use the electrical signal
generated by a microphone to change the
frequency of a radio wave as the signal
varies. This is called “frequency
modulation” or “FM.”
Just as we did for amplitude
modulation, let’s suppose we have a tone
that has been turned into an electrical
signal. When we modulate a radio wave
using frequency modulation, it looks
something like the diagram on the next
slide.
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Frequency Modulation (FM)
See how the wave height (amplitude)
stays the same? With FM, it is the
frequency or distance between the waves
that changes.
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AM and FM Compared
Compare the two modulation types side by side.
The good news is that you won’t have to know that
much about either one for the exam, BUT it is
still good to understand how they are different!
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FM Bandwidth
Now on to some more stuff you
really do need to know.
The approximate bandwidth of a
frequency-modulated voice signal is
between 5 and 15 kHz. This is much
greater than the 2 to 3 kHz
bandwidth of a SSB signal, so it
requires a lot of room. However, FM
signals are generally very clear and
noise free.
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Uses of FM
Because of its large
bandwidth, FM is generally best
suited for local use on VHF and
UHF bands. In fact, FM is the
type of modulation is most
commonly used for VHF and UHF
voice repeaters.
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SSB and FM
The bottom line is that if you
are concerned about voice quality,
you want to go with FM. However, if
you are concerned about bandwidth,
you want to go with SSB. The
primary advantage of single sideband
over FM for voice transmissions is
that SSB signals use much less
bandwidth than FM signals.
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Amateur TV – the Biggest
Bandwidth Hog
Some amateur operators enjoy
sending fast-scan TV over
amateur radio. Sending an
audio and video signal requires
a lot of bandwidth. The normal
bandwidth required for a
conventional fast-scan TV
transmission using combined
video and audio on the 70centimeter band is about 6 MHz!
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Amateur Radio and the
Internet
As we will soon see, amateur
radio uses the Internet along with
radios to communicate. Some amateur
radio stations are set up to allow
other stations to access the
Internet through these special
stations. The name given to an
amateur radio station that is used
to connect other amateur stations to
the Internet is a “gateway.”
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Check-Up Time!
Now let’s try the questions from
this group.
You should make a note of any that
you miss for later review.
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T6A01
What are phone transmissions?
A. The use of telephones to set up an
amateur radio contact
B. A phone patch between amateur
radio and the telephone system
C. Voice transmissions by radio
D. Placing the telephone handset near
a radio transceiver's microphone and
speaker to relay a telephone call
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T6A01 Answer - C
In the radio world, voice
transmissions are called
"phone" transmissions.
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T6A02
Which of the following is a
form of amplitude modulation?
A.
B.
C.
D.
Frequency modulation
Phase modulation
Single sideband
Phase shift keying
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T6A02 Answer - C
Amplitude modulation adds
information to a radio wave by
changing the amplitude or
height of that radio wave. In
the process, it creates the
main carrier wave and two
sidebands, an upper sideband,
and a lower sideband.
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T6A03
What name is given to an
amateur radio station that is
used to connect other amateur
stations to the Internet?
A.
B.
C.
D.
A
A
A
A
gateway
repeater
digipeater
beacon station
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T6A03 Answer - A
A station that provides a
connection to the Internet is a
gateway station.
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T6A04
Which type of voice modulation is
most often used for long distance
and weak signal contacts on the VHF
and UHF bands?
A.
B.
C.
D.
FM
AM
SSB
PM
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T6A04 Answer - C
For long distance
communication, the modulation
choice is always SSB (single
sideband). It doesn’t sound as
clear as AM or FM, but it packs
a lot of power into a narrow
bandwidth signal.
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T6A05
Which type of modulation is
most commonly used for VHF and
UHF voice repeaters?
A.
B.
C.
D.
AM
SSB
PSK
FM
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T6A05 Answer - D
FM is always the modulation
type of choice for VHF and UHF
repeaters. It takes a lot of
bandwidth and does not go very
far, but it produces a clear
voice signal for the repeater
to retransmit.
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T6A06
Which emission type has the
narrowest bandwidth?
A.
B.
C.
D.
FM voice
SSB voice
CW
Slow-scan TV
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T6A06 Answer - C
CW (or continuous wave) is
used for sending Morse code.
It is simply an unmodulated
signal that can be turned on or
off. Because CW is such a
narrow bandwidth, several code
stations can use the same width
of frequency as one SSB signal.
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T6A07
Which sideband is normally used
for VHF and UHF SSB
communications?
A.
B.
C.
D.
Upper sideband
Lower sideband
Suppressed sideband
Inverted sideband
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T6A07 Answer - A
Either sideband would work
just fine, but for effective
communication, everyone has to
be on the same sideband.
Because of that, by agreement,
everyone normally uses USB
(upper sideband) for VHF and
UHF sideband transmissions.
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T6A08
What is the primary advantage of single
sideband over FM for voice transmissions?
A. SSB signals are easier to tune in than FM
signals
B. SSB signals are less likely to be
bothered by noise interference than FM
signals.
C. SSB signals use much less bandwidth than
FM signals
D. SSB signals have no advantages at all in
comparison to other modes.
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T6A08 Answer - C
The biggest advantage of SSB
is that it has a much narrower
bandwidth than FM. That means
more people can use the same
amount of frequency spectrum to
communicate.
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T6A09
What is the approximate
bandwidth of a single-sideband
voice signal?
A.
B.
C.
D.
1 kHz
2 kHz
Between 3 and 6 kHz
Between 2 and 3 kHz
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T6A09 Answer - D
Bandwidth of a signal is one
of those things every radio
amateur should know, and not
just for the test. A good
clean SSB signal should be no
more than 2 to 3 kHz
(kilohertz) wide
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T6A10
What is the approximate
bandwidth of a frequencymodulated voice signal?
A.
B.
C.
D.
Less than
About 150
Between 5
More than
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500 Hz
kHz
and 15 kHz
30 kHz
58
T6A10 Answer - C
Here’s why bandwidth is
important. A clean FM signal is 5
to 15 kHz (kilohertz) wide. As you
can see, the widest FM signal takes
up five times as much bandwidth as
the widest SSB signal. (15 kHz
compared to 3 kHz.) FM sounds much
clearer than sideband, but the price
for that nice sound is bandwidth.
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T6A11
What is the normal bandwidth
required for a conventional fastscan TV transmission using combined
video and audio on the 70-centimeter
band?
A.
B.
C.
D.
More than 10 MHz
About 6 MHz
About 3 MHz
About 1 MHz
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T6A11 Answer - B
Yes, hams do television, but
it takes a lot of bandwidth –
about 6 MHz (megahertz). As
you can see, there are four
bandwidths you need to know,
but knowing them will help you
understand the advantages and
disadvantages of SSB, FM and
fast scan TV.
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Group T6B
Group T6B covers voice
communications, as well as the
popular digital communication
modes, EchoLink and IRLP .
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Echolink and IRLP
Many amateur radio operators use
the Internet as an additional
communications tool using two very
powerful software tools, Echolink
and IRLP (Internet Radio Linking
Project). Both of these tools can
put the world at the fingertips of
the Technician licensee with a
computer or simple handheld radio!
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Echolink
Echolink is a program available free to
any licensed amateur radio operator.
Information is transmitted between
stations using Echolink by means of the
Internet. When installed on your home
computer, it allows you to talk to
thousands of other hams around the world
via the Internet, similar to AOL instant
voice messaging. But it does so much
more. As a licensed ham, it also allows
you to connect to repeaters and other
amateur stations all over the world.
Using Echolink, you can log into a
repeater in another state or country and
chat with hams all over the world.
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Echolink
Screenshot of the free Echolink
program.
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How Echolink Works
Any licensed amateur radio operator may
operate on the Echolink system. Echolink allows
computer-to-radio linking for voice transmission.
All you need is a computer with a sound card and
microphone or headset, an internet connection and
the Echolink software. You can download the
software for free at http://echolink.org/.
Once you have downloaded and installed the
software, you’ll have to register online. As soon
as your license is verified, you will be ready to
connect. If you have a computer, Echolink will
allow you to get on the air even before you get
your first radio.
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IRLP
Another very popular use of the Internet for
Amateur Communications is IRPL. The abbreviation
IRLP means Internet Radio Linking Project. Like
Echolink, IRLP describe is a method of linking
between two or more amateur stations using the
Internet.
Unlike Echolink, you use your radio to contact
an IRPL station which is usually a repeater. That
repeater then uses the Internet to establish
contact with another IRLP station, also usually a
repeater. When the two repeaters are connected
via IRLP, operators on either end can use the
local repeaters to communicate with each other .
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How IRPL Works
IRLP uses a standard called “Voice over
Internet protocol” or “VoIP” to transfer data and
voice over the Internet. If you have an IRLP
repeater in your area, you can use your portable
transceiver to select a specific IRLP “node” by
using the keypad to transmit the IRLP “node
numbers.”
An IRLP node is a station connected to IRLP.
The node number is a number that identifies that
station to IRLP, and allows IRPL to connect you
with that station. For more information, visit
www.irlp.net.
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More on Echolink and IRLP
Echolink and IRLP both use Voice over
Internet protocol (VoIP) to connect
amateur stations. This technology allows
for fun and inexpensive communications
between hams all over the world, as well
as providing another link for emergencies.
Be sure to give both a try!
And next time you are listing to a
local 2 meter repeater, you may hear a
brief tone and then a station from Russia
calling CQ on a 2-meter repeater. If so,
you are almost certainly listening to an
Internet linked DX station!
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Locating VoIP Nodes
You can find a list of active
nodes using VoIP in a repeater
directory or on the Internet.
Be sure to check them out!
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Check-Up Time!
Now let’s try the questions from
this group.
You should make a note of any that
you miss for later review.
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T6B01
How is information transmitted
between stations using
Echolink?
A.
B.
C.
D.
APRS
PSK31
Internet
Atmospheric ducting
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T6B01 Answer - C
Echolink is a free computer
program that allows licensed
amateurs to remotely access other
stations and repeaters via the
Internet. With Echolink, you can
use your computer to talk directly
to other hams all over the world
using the Internet only, or you can
log into a remote repeater or
station set up for Echolink, and
work stations in that area.
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T6B02
What does the abbreviation IRLP
mean?
A. Internet Radio Linking Project
B. Internet Relay Language Protocol
C. International Repeater Linking
Project
D. International Radio Linking
Project
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T6B02 Answer - A
IRLP stands for "Internet
Repeater Linking Project." IRLP
uses the Internet to link repeaters.
Using your radio, you can access an
IRLP repeater and by entering a
code, you can link that repeater to
one of many repeaters worldwide. By
linking the repeaters, you can carry
on a conversation with other hams
all over the world using only your
VHF or UHF radio. How cool is that?
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T6B03
Who may operate on the Echolink
system?
A. Only club stations
B. Any licensed amateur radio
operator
C. Technician class licensed amateur
radio operators only
D. Any person, licensed or not, who
is registered with the Echolink
system
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T6B03 Answer - B
Any licensed amateur operator may
use Echolink. If you want to use it
with your computer, all you have to
do is download and install the
program (it's free), and register.
The registration process verifies
that you are a licensed amateur.
From that point, have fun! (By the
way, this is an excellent way to put
that license to work, even before
you get your first radio!)
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T6B04
What technology do Echolink and
IRLP have in common?
A.
B.
C.
D.
Voice over Internet protocol
Ionospheric propagation
AC power lines
PSK31
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T6B04 Answer - A
Both Echolink and IRLP use
VoIP, or "voice over the
Internet protocol." VoIP is a
standardized system for
transmitting speech or data
over the Internet.
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T6B05
What method is used to transfer
data by IRLP?
A. VHF Packet radio
B. PSK31
C. Voice over Internet protocol
D. None of these answers are
correct
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T6B05 Answer - C
VoIP is a standardized system
for transmitting data or speech
over the Internet. It can
transmit data as well as voice
because the data is translated
into sounds for transmission.
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T6B06
What does the term IRLP describe?
A. A method of encrypting data
B. A method of linking between two or
more amateur stations using the
Internet
C. A low powered radio using infrared frequencies
D. An international logging program.
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T6B06 Answer - B
IRLP (Internet Repeater
Linking Project) is used to
connect two amateur stations
with the appropriate software
and access to the Internet.
Most often, it is used by an
amateur to link two repeaters
together for long haul
communications.
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T6B07
Which one of the following
allows computer-to-radio
linking for voice transmission?
A.
B.
C.
D.
Grid modulation
EchoLink
AMTOR
Multiplex
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T6B07 Answer - B
Echolink allows an amateur to
link his or her computer to any
IRLP-capable repeater or
station worldwide.
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T6B08
What are you listening to if you
hear a brief tone and then a station
from Russia calling CQ on a 2-meter
repeater?
A.
B.
C.
D.
An ionospheric band opening on VHF
A prohibited transmission
An Internet linked DX station
None of these answers are correct
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T6B08 Answer - C
If you hear a Russian CQ and call
on the local two-meter repeater, you
can bet that it is from a ham linked
via the Internet. The link could be
either through Echolink or IRLP. By
the way, "DX" means "distant
station.“ (Also bear in mind that
calling CQ on a local repeater is
not commonly accepted “good amateur
practice”!)
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T6B10
Where might you find a list of
active nodes using VoIP?
A. The FCC Rulebook
B. From your local emergency
coordinator
C. A repeater directory or the
Internet
D. The local repeater frequency
coordinator
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T6B10 Answer - C
Current repeater directories
often indicate whether the
repeater is using one of the
VoIP protocols. Also, there
are many websites on the
Internet that show repeaters
currently using VoIP.
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T6B11
When using a portable
transceiver how do you select a
specific IRLP node?
A. Choose a specific CTCSS tone
B. Choose the correct DSC tone
C. Access the repeater autopatch
D. Use the keypad to transmit
the IRLP node numbers
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T6B11 Answer - D
Most VHF and UHF transceivers
have keypads, either on the radio,
or more commonly, on the microphone.
If you want to access an IRLP
repeater from your radio, you need
to key the "node number" of the
distant repeater into the keypad.
This sends a signal to the local
repeater. The local repeater then
contacts and links up with the
distant repeater via the Internet.
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Group T6C
Group T6C covers several types of nonvoice communications, such as image
communications, data, CW, packet, and
PSK31. It also covers Morse code
techniques and amateur radio Q signals.
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Digital Communications
Hams use a number of other
digital communications methods
that do not require the
Internet. Some, such as
packet, have been around since
the early days of computers,
while others, such as PSK31 are
fairly new. All are lots of
fun!
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Packet Radio
Packet radio, or simply packet, is one
example of a digital communications
method. Packet has been around amateur
radio since desktop computers became
widely available in the 1980’s. It uses
special software, a computer connected to
a radio, and either a “terminal node
controller” or a sound card, to send text
or data on a computer over the air. It
sends the text or data in “packets” that
include information that allows the
receiving computer to check the incoming
packet for errors. If errors are
detected, the receiving station will
automatically request a resend of the data
to insure 100% error free reception.
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APRS
The term APRS means “Automatic Position
Reporting System.” APRS is system that
automatically tracks the location of an
amateur station, usually a mobile or
portable station. Along with your normal
radio, you’ll need a global positioning
system receiver for sending automatic
location reports from your station via
APRS.
APRS has a lot of potential for use
during emergencies!
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Fast Scan Television
If you want to be on TV, amateur radio gives
you the chance. Since the 1960’s, hams have been
experimenting with television transmissions. At
first, utilizing very bulky equipment, hams used
slow scan television to transmit still pictures
between stations. Pretty high tech stuff for that
time, but not too impressive today.
With the advent of inexpensive video cameras,
computers and VHF repeaters specially designed for
video transmission, hams can use fast scan
television. Fast scan television uses the NTSC
standard. NTSC, short for “the National
Television System(s) Committee,” has developed a
uniform standard for fast scan color television
signals.
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Point-to-Point Digital
Message Forwarding
Point-to-point digital message
forwarding is yet another method if
communications available to the Technician
class operator in the 219 - 220 MHz
frequency range.
The FCC has said that it encourages
hams to develop and implement digital
message forwarding system networks that
can be used for emergency and national
defense communications purposes, and to
connect local packet nodes for this
purpose.
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PSK31
PSK31 is a yet another fun digital
mode. It requires only a radio and
computer with a sound card, along with
free software to work the world. PSK31 is
a low-rate data transmission mode that
works well in noisy conditions. It does
not require a lot of power.
PSK31 uses the computer and sound card
to generate PSK (phase shift keying)
signals that are transmitted and decoded
at the other end. Unlike packet, PSK31 is
not error correcting, but it is still a
great mode!
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PSK31 Using Digipan
Software
Digipan is a free software package that will let you get
on the air with PSK. Along with the software, you’ll need a
computer with a soundcard, a radio, and a simple interface.
For more information, visit www.digipan.net.
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Morse Code – The First
Digital!
Many aspiring hams are put off
from learning Morse code because
they believe it is too hard to
learn. That is a real shame,
because while it does take a little
effort to master the code, it also
provides some real opportunity for
long distance (DX) contacts, as well
as special interest operations such
as QRP (low power operating).
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Morse Code – How To Learn
It
This study guide is not intended to teach
Morse code. There are lots of ways to learn the
code, including other hams, computer programs, or
tapes. No matter how you choose to learn, don’t
make this too hard for yourself. There are two
things you need to remember.
First, don’t try to memorize dots and dashes.
Instead, memorize the sound of each letter or
number.
Second, once you have memorized the sounds of
just 26 letters 10 numerals and 5 punctuation
marks, you will almost certainly be able to pass
the five words per minute test.
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Why Learn Morse Code?
There are three reasons.
First,
code test,
frequency)
privileges
once you as a Technician are able to pass the
you will be given additional HF (high
privileges. You can begin using those
to send and receive code right away!
Second, when you pass the code, you have gotten the
hardest requirement for General out of the way. Pass
the General exam, and all the HF bands are yours for the
asking.
Third, even if you never intend to upgrade or use
Morse code, one practical reason for being able to copy
CW when using repeaters is to recognize a repeater ID
sent in Morse code.
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Sending Morse Code
OK, one other thing you may need
to know for the Technician exam, is
that when you first learn Morse
code, you almost always send faster
than you can receive. Because of
that, you should be careful not to
send any faster than the speed you
can reliably receive. Why? Because
the ham at the other end has no way
of knowing that you cannot copy as
fast as you send!
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Q Signals
Back in the early days of radio when
the only form of radio communications was
Morse code, operators came up with several
abbreviations to move things along.
Several of these abbreviations began with
the letter “Q” and are still used by hams
today. These abbreviations serve the same
purpose as “10 codes” for police and
emergency workers. Here are some
examples. Although they were originally
designed for telegraphy, many hams now use
them on voice.
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QRM – Interference from
other Stations
When stations operate on
frequencies that are too close to
each other, they may interfere with
each other’s ability to hear the
stations they are trying to
communicate with. The "Q" signal
you would use to tell another
station that you are receiving
interference from other stations is
“QRM.” Example: “Could you please
repeat? I am getting some heavy QRM
here.”
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QSY – Changing Frequency
If you want to ask another person
to change frequency, or announce
that you are changing frequency, you
use “QSY.” Example: “Jane, we’re
close enough that we don’t need to
use the repeater. Let’s QSY to
146.52.”
A complete list of Q-Signals can
be found at www.arrl.org/files/
bbs/general/q-sigs.
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Check-Up Time!
Now let’s try the questions from
this group.
You should make a note of any that
you miss for later review.
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T6C01
Which of the following is an
example of a digital
communications method?
A.
B.
C.
D.
Single sideband voice
Amateur television
FM voice
Packet radio
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T6C01 Answer - D
Packet radio is a form of digital
communications. In digital
communications, data is translated into a
string of zeros and ones by switching a
signal off or on. Off usually represents
a zero and on usually represents a one.
This series of ons and offs is decoded by
the receiver and turned into usable text.
Packet radio sends this series of digits
in packets along with a checking code so
that the receiver can determine if the
signal was received correctly. If not, it
can signal the same packet to be sent
again until it is correctly received.
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T6C02
What does the term APRS mean?
A. Automatic Position Reporting
System
B. Associated Public Radio
Station
C. Auto Planning Radio Set-up
D. Advanced Polar Radio System
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T6C02 Answer - A
APRS, or Automatic Position
Reporting System, uses Global
Positioning System (GPS)
technology to allow amateurs to
track the locations of other
hams via radio and computer.
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T6C03
What item is required along with
your normal radio for sending
automatic location reports?
A. A connection to the vehicle
speedometer
B. A connection to a WWV receiver
C. A connection to a broadcast FM
sub-carrier receiver
D. A global positioning system
receiver
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T6C03 Answer - D
The Global Positioning System
(GPS) receiver is required to
determine the location of the
station to be tracked so that
it can send that location out
to the APRS system.
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T6C04
What type of transmission is
indicated by the term NTSC?
A. A Normal Transmission mode in
Static Circuit
B. A special mode for earth satellite
uplink
C. A standard fast scan color
television signal
D. A frame compression scheme for TV
signal
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T6C04 Answer - C
NTSC stands for National
Television Standards Committee.
This group has developed the
standard for fast scan
television signals.
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T6C05
What emission mode may be used by a
Technician class operator in the 219
- 220 MHz frequency range?
A. Slow-scan television
B. Point-to-point digital message
forwarding
C. FM voice
D. Fast-scan television
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T6C05 Answer - B
According to Part 97, operators
using this frequency band are
limited to data transmissions. All
of the transmissions listed in
Answers A, C, and D are something
other than data transmissions so
they are not allowed in this
frequency band. Only Answer B
mentions a data transmission so this
is the right choice.
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T6C06
What does the abbreviation PSK
mean?
A.
B.
C.
D.
Pulse Shift Keying
Phase Shift Keying
Packet Short Keying
Phased Slide Keying
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T6C06 Answer - B
PSK is short for phased shift
keying.
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T6C07
What is PSK31?
A. A high-rate data transmission mode
used to transmit files
B. A method of reducing noise
interference to FM signals
C. A type of television signal
D. A low-rate data transmission mode
that works well in noisy conditions
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T6C07 Answer - D
PSK31 is an excellent mode
for working DX (distant
stations) with very little
power. All you need is a radio
with a sound card and PSK31
software, a computer, and a
simple interface to connect the
computer to the radio.
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T6C08
What sending speed is recommended
when using Morse code?
A. Only speeds below five WPM
B. The highest speed your keyer will
operate
C. Any speed at which you can
reliably receive
D. The highest speed at which you can
control the keyer
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T6C08 Answer - C
Most people just learning code
can send much faster than they can
copy. If you send code faster than
you can copy, the person at the
other end won't know you can't copy
that fast. When it's the other
ham's turn to send, you are likely
to get code sent back to you at the
speed you sent, and you will soon be
lost!
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T6C09
What is a practical reason for being able
to copy CW when using repeaters?
A. To send and receive messages others
cannot overhear
B. To conform with FCC licensing
requirements
C. To decode packet radio transmissions
D. To recognize a repeater ID sent in Morse
code
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T6C09 Answer - D
Before the code-free license,
everyone who wanted to be a ham had
to learn Morse code to get a
license, so when repeaters sent
their ID in Morse code, everyone
could understand it. However,
learning Morse code will not only
let you copy the repeater ID, it
will be your ticket to the General
Class license and the world of high
frequency (HF) communications.
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T6C10
What is the "Q" signal used to
indicate that you are receiving
interference from other
stations?
A.
B.
C.
D.
QRM
QRN
QTH
QSB
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T6C10 Answer - A
"Q" signals are used by amateurs
to convey a lot of information in a
short form. In that way, they are
somewhat like the "ten codes" used
by police, emergency personnel and
CB'ers. One of the more common Q
codes is this one - QRM - which
means you are receiving interference
from other stations near or on your
frequency.
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T6C11
What is the "Q" signal used to
indicate that you are changing
frequency?
A.
B.
C.
D.
QRU
QSY
QSL
QRZ
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T6C11 Answer - B
Here is another Q code. QSY
means you are changing frequency or
that you would like the other
operator to do so. Q codes are
particularly useful when you are
using Morse code since they can
convey a lot of information in only
three letters, but they are also
frequently heard on phone (voice) as
well.
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Six Down, Four to Go!
This concludes Study Guide # 6.
Once you are satisfied that you can answer
80% of the questions in this Sub-element, you
are ready to move on to Study Guide # 7.
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