Operation Manual

VX-170 OPERATING MANUAL 23
CTCSS/DCS/EPCS OPERATION
CTCSS OPERATION
Many repeater systems require that a very-low-frequency audio tone be superimposed on
your FM carrier in order to activate the repeater. This helps prevent false activation of the
repeater by radar or spurious signals from other transmitters. This tone system, called
“CTCSS” (Continuous Tone Coded Squelch System), is included in your VX-170, and is
very easy to activate.
CTCSS setup involves two actions: setting the Tone Mode and then setting of
the Tone Frequency. These actions are set up by using the [1(SQ TYP)] key
and [2(CODE)] keys.
1. Press the
[
F
]
key, then press the
[
1
(
SQ TYP
)]
key to enable selection of the CTCSS/
DCS/ECS mode.
2. Rotate the DIAL knob so that “
TONETONE
TONETONE
TONE” indication appears on the
display; this activates the CTCSS Encoder, for access to repeat-
ers requiring a CTCSS tone.
3. Rotation of the DIAL knob one more “click” in step “2” above
will cause the “
TSQLTSQL
TSQLTSQL
TSQL” notation to appear. When “
TSQLTSQL
TSQLTSQL
TSQL” is dis-
played, this means that the Tone SQueLch system is active, which
mutes your VX-170’s receiver until it receives a call from an-
other radio sending out a matching CTCSS tone. This can help keep your radio quiet
until a specific call is received, which may be helpful while operating in congested
areas of the band.
1) You may notice a “REV TN” indication on the display while you rotate
the DIAL knob in this step; this means that the Reverse Tone Squelch
system is active, which mutes your VX-170’s receiver (instead of opening
the squelch) when it receives a call from the radio sending a matched CTCSS tone.
The “ ” icon will blink on the display when the Reverse Tone Squelch system is
activated.
2) You may notice the “DCS” and “ECS” indications on the display while you ro-
tate the DIAL knob still more. We’ll discuss the Digital Code Squelch system (for
“DCS”) and Enhanced Paging & Code Squelch (for “ECS”) later.
4. When you have made your selection of the CTCSS tone mode, press the PTT switch
to save the new setting.
5. Press the
[
F
]
key, then press the
[
2
(
CODE
)]
key to
enable adjustment
of the CTCSS fre-
quency.
6. Rotate the DIAL knob until the display
indicates the Tone Frequency you need to
CTCSS TONE FREQUENCY
(
Hz
)
67.0 69.3 71.9 74.4 77.0 79.7
82.5 85.4 88.5 91.5 94.8 97.4
100.0 103.5 107.2 110.9 114.8 118.8
123.0 127.3 131.8 136.5 141.3 146.2
151.4 156.7 159.8 162.2 165.5 167.9
171.3 173.8 177.3 179.9 183.5 186.2
189.9 192.8 196.6 199.5 203.5 206.5
210.7 218.1 225.7 229.1 233.6 241.8
250.3 254.1 – – – –