NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00
Issue 4
Page 3-6
3.7.2
Brightness Switch
The
BRIGHT
switch controls the brightness of the radio display. Momentarily press it to the right ‘
+
’ to
increment the display brightness by one level and to the left ‘
−
’ to decrement by one level. There are
seven brightness levels from which to select. The radio will retain the display brightness information
when turned off, but on power up will limit brightness to a maximum of level five.
3.7.3 Squelch
Pushbutton
Pressing the
SQ
(squelch) test button over-rides all squelch logic, and lets the radio’s unsquelched audio
receive signal pass to the aircraft’s audio system. The squelch test function is useful for monitoring
activity on the radio when tones prevent the squelch from opening, or to verify volume settings or radio
function.
3.8
Channel Display{tc "1.4.6
Channel Display"}
For each channel stored in the radio, there are three data lines; the ID line, the RX line, and the TX line.
Depending on the position of the
DISP
switch, one of these data lines will be shown on the top row of the
display. Regardless of which of the three is being displayed, the channel number will always show on the
far left hand side and RX/TX functions will be operational.
3.8.1
ID Display Line
The ID line includes the channel number, the channel label or name, the scan list flag, and the priority
scan channel flag. A typical ID display line might look like this:
01
FORESTRY sc p
1
Channel Label
Scan Flags
The label for each channel is an alphanumeric name that may be up to 10 characters long. The channel
name has no effect on radio operation, and is provided for operator convenience in identifying the
selected channel.
The scan list flag indicates whether or not the radio monitors the channel during scanning. The ‘sc’
character means that the channel is in the scan list. A dash ‘
−
’ indicates the channel is not in the scan list.
The ‘p1’ character means that the channel is the priority scan channel. A dash ‘
−
’ indicates the channel is
not selected as a priority channel.
If the radio is a NPX138N, there will also be a bandwidth flag displayed on the ID line. A typical
NPX138N ID line might look like this:
01
FORESTRY
sc p
1
Channel Label
Bandwidth
Scan
Flags
The bandwidth flag indicates the current modulation acceptance and transmit deviation mode. A ‘ ’
character indicates that the channel is operating in wide-band (± 5.0 kHz Rated System Deviation) mode.
An ‘ ’ character indicates that the channel is operating in narrow-band (± 2.5 kHz Rated System Deviation)
mode (refer to section 3.13).
ENG-FORM: 806-0115.DOT
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