Special Operations T7

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Special Operations (T7)
Some of the diverse and interesting amateur
radio activities!
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In this Section

• Repeaters
• Satellites
• Internet Linking
• Various Field Operations

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Repeaters

• Repeater An amateur station that simultaneously
  retransmits the transmission of another amateur
  station on a different channel or channels
• Why? A powerful repeater transmitter located at
  altitude greatly increases the effective range of
  weaker hand held and mobile radios.

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Repeaters
In order to use a repeater, you must first know
the repeaters transmit frequency and offset. The
offset is the difference in the
repeaters transmit and receive
frequencies. Most modern radios will
calculate the offset for you.
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A Two-Meter Repeater in Action
Output Freq 146.625 MHz
Input Freq 146.025 MHz
Offset - 600 kHz (0.6 MHz)
60 miles
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A 70-cm (440) Repeater in Action
Output Freq 449.50 MHz
Input Freq 444.50 MHz
Offset - 5 MHz
60 miles
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Repeaters

• Squelch A squelch circuit keeps the radio
  speaker turned off until sufficient RF energy is
  present at the receiver. This keeps the radio
  quiet until a signal is received. In a repeater,
  the squelch also turns on the transmitter.
• PL Tones A sub-audible tone which your receiver
  can listen for. If set, your radio will only
  open the squelch if it detects the tone.

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Repeaters

• At the end of each transmission through a
  repeater, you will hear a roger beep or
  courtesy tone (a short beep, or series of
  beeps).
• Do not begin your transmission until after you
  hear the courtesy beep.
• Do not confuse the roger beep with the PL tone.

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Repeater Operations

• Listen! If nobody is there, then the repeater is
  not in use. Give your call sign once.
• If the repeater is busy, wait for a break and
  give your call sign ONCE.
• DO NOT KER-CHUNK THE REPEATER
• Observe rotation, if there is one.
• When calling another station, always give the
  other stations call sign first, then yours.
• ID every 10 minutes and at the end of the
  conversation (QSO), you need not ID after every
  exchange.

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T5C04 Why should you pause briefly between
transmissions when using a repeater? A. To let
your radio cool off B. To reach for pencil and
paper so you can take notes C. To listen for
anyone wanting to break in D. To dial up the
repeater's autopatch
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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. FM B.
AM C. SSB D. PM
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T5C10 How might you find out if you could
communicate with a station using simplex instead
of a repeater? A. Check the repeater input
frequency to see if you can hear the other
station B. Check to see if you can hear the
other station on a different frequency band C.
Check to see if you can hear a more distant
repeater D. Check to see if a third station can
hear both of you
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Some Final Thoughts -- Repeaters

• Open Most repeaters are open to anyone.
• Closed Use is restricted to members.
• Coordination Prevents repeaters from
  interfering with each other!

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Satellite Communication

• With modest equipment, amateurs can send and
  receive communications through satellites.
• VHF and UHF frequencies
• Directional Antennas
• Think of it as a repeater in the sky!

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Satellite Tracking
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T7B02 How much power should you use to transmit
when using an amateur satellite? A. The maximum
power of your transmitter B. The minimum amount
of power needed to complete the contact C. No
more than half the rating of your linear
amplifier D. Never more than 1 watt
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T7B09 What is a satellite sub-band? A. A
special frequency for talking to submarines B. A
frequency range limited to Extra Class licensees
C. A portion of a band where satellite
operations are permitted D. An obsolete term
that has no meaning
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Some folks really LOVE satellites!
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Voice over Internet (VoIP)

• With a small HT, you can talk to people all over
  the world!
• IRLP
• Internet Radio Linking Project
• Repeater-to-Repeater
• EchoLink
• Computer-to-Radio Linking

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IRLP

• Link distant repeaters via the Internet
• Your low-power radio can connect you anywhere!

• Most nodes are open to all amateurs!

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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. An ionospheric band
opening on VHF B. A prohibited transmission C. An
Internet linked DX station D. None of these
answers are correct
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T6B04 What technology do Echolink and IRLP have
in common? A. Voice over Internet protocol B.
Ionospheric propagation C. AC power lines D. PSK31
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EchoLink
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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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Radio Field Operations

• Transmitter Hunts
• Contests
• Special Event Stations
• Field Day

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ARRL Field Day (Late June)

• Each June, we go out in the field and operate 24
  hours off the grid. Its a chance to really
  test our radio skills!!

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T7A04 What would be a good thing to have when
operating from a location that includes lots of
crowd noise? A. A portable bullhorn B. An
encrypted radio C. A combination headset and
microphone D. A pulse noise blanker
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T7A07 What is a popular operating activity that
involves contacting as many stations as possible
during a specified period of time? A.
Contesting B. Net operations C. Public service
events D. Simulated emergency exercises
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T7A06 Which of these items would be the most
useful for a hidden transmitter hunt? A.
Binoculars and a compass B. A directional
antenna C. A calibrated noise bridge D.
Calibrated SWR meter
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Questions?