6-3. tone and ctcss operation – Kenwood TM-741A User Manual
Page 42
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4-6-3. Tone and CTCSS Operation
Some repeaters require the use of a control signal to
activate the repeater. Several different methods are
currently in use. In the United States sub-audible tones
are sometimes used, 38 different sub-audible
frequencies being possible.
The CTCSS function has been activated the radio will
not open squelch until the proper tone is received.
IN EUROPE AND UNITED KINGDOM a 1750 Hz tone
is used in transmit. Press and hold the microphone 1750
key to transmit with the access tone, you need not press
the PTT switch.
Since this tone is required in Europe and the United
Kingdom a 1750 Hz tone encoder is included with
models delivered to these countries.
• Tone Frequency Selection
Each band can be selected the Tone Frequency
independently.
1. Press the F key for longer than 1 second. The F
indicator will flash. Press the TONE key. The current
tone frequency will show in the display.
2. Rotate the Tuning control or press the microphone
UP/DWN key to select the desired tone frequency.
3. When the desired tone frequency is selected, the
previous mode is resumed 10 seconds after selection
or when the any front panel key is pressed.
Tone Frequency (Hz)
67.0
82.5
97.4
114.8 136.5 162.2 192.8 233.6
71.9
85.4
100.0 118.8 141.3 167.9 203.5 241.8
74.4
88.5
103.5 123.0 146.2 173.8 210.7 250.3
77.0
91.5
107.2 127.3 151.4 179.9 218.1
79.7
94.8
110.9 131.8 156.7 186.2 225.7
• Tone/CTCSS Operation
Press the TONE key and select the desired Tone mode.
When the T indicator appears in the display the
transmitter will transmit the desired tone. Tone signals
can be transmitted.
When the CTCSS indicator appears in the display the
transceiver will transmit the desired tone and will also
operate in the Tone Squelch mode, i.e. the squelch will
not open until the proper tone is received as a portion of
the incoming receive signal.
When no indicator is on, the radio will not make use of
either tone feature. Set TONE to OFF for transmission
with a repeater or transmission without tone squelch
(CTCSS).
No indicator
-► T
CTCSS
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