Download Chapter 6 - Good Operating Practices

Chapter 6 – Good Operating Practices
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Operating Skill
SSB Voice Operating
Operating CW
Tuning Up
Amateur Radio Internet Gateways
Bandwidth
Spurious Signals
Signal Purity
Interference with Other Services
T6-1
Operating Skill
• Band plans are voluntary agreements between
operators about how to use the frequencies of an
particular amateur band.
– Band plans are available at www.arrl.org.
• First rule of good operating is to always listen
before you transmit.
• Another good rule is to talk during a contact
(QSO) as you would during a face-to-face
conversation.
T6-2
Band Plan – 2 meters
144.0
145.0
In
CW
146.0
Out
SSB, Weak Signal
147.0
In
Out
148.0
Out
Repeater
In
FM Simplex
Frequency
Usage
Frequency
Usage
144.00-144.05
EME (CW)
145.20-145.50
Repeater Outputs
144.05-144.10
General CW
145.50-145.80
Misc Experimental
144.10-144.20
EME & SSB
145.80-146.00
OSCAR Subband
144.200
National SSB Calling
146.01-146.37
Repeater Inputs
144.20-144.275
SSB Operations
146.40-146.58
FM Simplex
144.275-144.300
Beacons
146.52
National FM Calling
144.30-144.50
OSCAR Subband
146.61-146.97
Repeater Outputs
144.50-144.60
Linear Translator Inputs
146.700-147.39
Repeater Outputs
144.60-144.90
Repeater Inputs
147.42-147.39
FM Simplex
144.90-145.10
Weak Signal SSB
147.60-147.99
Repeater Inputs
145.10-145.20
Linear Translator Outputs
T6-3
FM Voice Operating
• Frequency modulation (FM) is popular mode on
VHF/UHF bands.
– Used on both repeaters and simplex modes
• Initiating a contact when frequency or repeater is
busy
– Wait until stations have ended QSO and then call
station
• Initiating a contact when frequency or repeater is
not being used.
– Simply give your call and indicate that you are
“listening”
T6-4
SSB Voice Operating
• Single side-band (SSB) is the most common voice
mode on HF.
• Amateurs normally use the upper sideband of a
SSB signal on frequencies higher than 14 Mhz
(including VHF and UHF).
• Keep It Plain and Simple
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Always speak slowly and clearly.
Avoid using CW abbreviations or Q signals on voice.
Use plain language and keep jargon to a minimum.
Use the phonetic alphabet if the other operator is having
problems copying your signal.
T6-5
SSB Voice Operating (Cont’d)
• Initiating A Contact
– Listen for stations in a QSO, wait until they have
finished and then call one of the stations
– Listen for a frequency not being used and call “CQ” for
a contact with any station
• CQ means “Seek You”: Calling any station
• Keep CQ calls short, typically a “3x3” format.
• You can optionally indicate your preference for a contact (DX
only, Europe only, particular state, contest participant, etc.)
T6-6
Operating CW
• Send Morse code at a speed you can reliably copy.
• The word “DE” is used prior to your call sign to
mean “from” or “this is.”
• Q signals are used during CW contacts .... not in
voice contacts.
• A DX station may be working “split” ... indicating
that the station is listening on a frequency or range
different from his transmit frequency.
T6-7
Operating CW
Some good guidelines when operating CW:
• Listen before transmitting.
• Send short CQs.
• Use only standard abbreviations.
• Use CW prosigns and Q signals properly
• Identify at the end of a QSO and every 10 minutes
during a QSO.
• Use RST signal report of Readability=5 only if
you have received 100% of what the other station
has sent.
T6-8
Operating CW
Example of a short CW QSO
CQ CQ CQ DE K0KTY K0KTY K0KTY K
K0KTY K0KTY DE K0RGR K0RGR KN
K0RGR DE K0KTY R TNX FER CALL. UR RST 579 579. QTH IS
ROCHESTER, MN ROCHESTER, MN. NAME IS JOHN JOHN.
HW CPY? DE K0KTY KN
R R DE K0RGR BT FB COPY JOHN. NAME HR IS BILL ES QTH IS
ALSO ROCHESTER, MN. RUNNING QRP RIG TO DIPOLE
ANTENNA. BK TO U BK BK
BK SOLID COPY BILL. HAVE TO RUN. 73 ES CUL DE K0KTY SK
73 DE K0RGR SK
T6-9
The RST System
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Signal reports when operating CW consists of
three digits representing:
– Readability (ranges from 1 to 5)
– Strength (ranges from 1 to 9)
– Tone (ranges from 1 to 9)
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Signal reports on SSB are two digit numbers
using the “RS” portion of the RST system.
– A report of “59 plus 20db” indicates that your report is
20 decibels higher than signal strength 9 on the
receiver S meter.
T6-10
The RST System
Readability
Strength
Tone
1-Unreadable
1-Faint signals bare perceptible
1-Sixty cycle ac or less, very rough
2-Barely readable
2-Very weak signals
2-Very rough ac, very harsh and broad
3-Readable with difficulty
3-Weak signals
3-Rough ac tone, rectified
4-Readable with no difficulty
4-Fair signals
4-Rough note, some filtering
5-Perfectly readable
5-Fairly good signals
5-Filtered rectified ac
6-Good signals
6-Filtered tone, trace of tipple
7-Moderately strong signals
7-Near pure tone, trace of ripple
8-Strong signals
8-Near perfect tone, trace modulation
9-Extremely strong signals
9-Perfect tone, no ripple or modulation
T6-11
Tuning Up
• To avoid on-the-air interference, connect your
transmitter to a “dummy load” while you tune up.
• Once the transmitter is tuned, disconnect the
dummy load and connect an antenna. Use an
antenna switch to change the connection.
• If you use an antenna tuner to match your antenna
with your transmitter, you may have to transmit a
brief low power signal to adjust the antenna tuner
circuit.
T6-12
Amateur Radio Internet Gateways
• Used to connect amateur stations with the internet.
• Uses the internet protocol known as VoIP (Voice
Over Internet Protocol).
• Gateway stations can be used to link repeaters
where two distant repeaters share signals using
VoIP.
• Popular amateur VoIP linking systems are IRLP
and Echolink
– KØRGR operates an Echolink node on the 146.625
2 meter repeater in Rochester
T6-13
Bandwidth
• The amount of radio-frequency spectrum that a
signal occupies is called its bandwidth.
• Receiver bandwidth determines how well you can
receive one signal in the presence of other signals
– Receiver bandwidth selectivity is determined by special
intermediate-frequency (IF) filters built into the
receiver.
– Some receivers have several IF filters for use when
receiving different emission modes.
– CW has the narrowest bandwidth of any emission
mode.
T6-14
Relative Emission Bandwidths
T6-15
Typical Emission Bandwidths
Emission Mode
Morse Code (CW)
Typical Bandwidth
250 to 500 Hz
Radio Teletype (RTTY)
250 to 500 Hz
SSB Voice
2 to 3 KHz
FM Voice
10 to 20 KHz
Television (Fast Scan)
6 MHz
T6-16
FM Bandwidth
• The frequency of the transmitted RF signal varies
with the strength of the modulating voice.
• The frequency deviation is the instantaneous
change in frequency for a given signal.
• FM bandwidth is twice the maximum frequency
deviation plus the maximum modulating audio
frequency:
BW = 2 x (D + M)
BW=bandwidth
D = maximum frequency deviation
M = maximum modulating audio frequency
T6-17
Signal Purity
• An amateur operator is responsible for the quality
of the signal transmitted from the amateur station.
• During CW operations, a chirp sound is a problem
when the transmitter shifts frequency slightly
when keyed.
– The problem usually occurs when the oscillator power
supply voltage changes as the transmitter is keyed.
– The problem can typically be eliminated by improving
the power supply voltage regulation.
T6-18
RF Interference With Other Services
• Receiver Overload
– Common type of TV and FM-broadcast interference
where a RF signal overloads the first RF amplifier stage
of the receiver.
– Most common type of interference caused by VHF and
UHF transmitters.
– For overload from a HF transmitter, a high pass
filter should be installed at the TV or FM receiver
antenna terminals as a first step to reduce or eliminate
receiver overload interference.
T6-19
RF Interference With Other Services
• Harmonic Interference
– Occurs when HF transmitters radiates at multiples of
the primary transmission frequency.
– May be cured or reduced at the transmitter by installing
a low pass filter.
– Amateur is responsible to eliminate harmonic
interference caused by HF transmissions.
• Telephone Interference
– Telephones contain interference protection circuitry.
– Interference may indicate that the telephone was not
equipped with interference protection when it was
manufactured.
T6-20
RF Interference With Other Services
HF Transmitter
TV Receiver
TX
Low pass
Filter
High pass filter
Low Pass Filter
Pass
High Pass Filter
Stop
Stop
Pass
freq
HF
TV
freq
HF
TV
T6-21