E F Johnson Company 2425720 사용자 설명서
5-4
Viking™ VP600 Portable Radio Operating Manual
Conventional Mode Features
When “Normal” is selected, the receiver unsquelches only if a carrier is detected.
Scanning and Project 25 NAC detection are not disabled with this mode selected. The
selected mode is in effect until it is manually changed again. Selecting another channel or
cycling power does not reselect a default condition. There is a programmable option to
display the monitor icon when the “Normal” mode is selected.
Scanning and Project 25 NAC detection are not disabled with this mode selected. The
selected mode is in effect until it is manually changed again. Selecting another channel or
cycling power does not reselect a default condition. There is a programmable option to
display the monitor icon when the “Normal” mode is selected.
5.4.2 Tone Call Guard Squelch
Tone-type Call Guard squelch uses subaudible CTCSS tones from 67-254.1 Hz. Although
there are 42 tones assigned, those above 33 (210.7 Hz) are normally not used because of
their close proximity to the voice band which starts at 300 Hz. In addition, tones 11 (97.4
Hz), 39 (69.3 Hz), 40 (206.5 Hz), 41 229.1 Hz), and 42 (254.1 Hz) are normally not used
because they may cause interference with adjacent tones.
there are 42 tones assigned, those above 33 (210.7 Hz) are normally not used because of
their close proximity to the voice band which starts at 300 Hz. In addition, tones 11 (97.4
Hz), 39 (69.3 Hz), 40 (206.5 Hz), 41 229.1 Hz), and 42 (254.1 Hz) are normally not used
because they may cause interference with adjacent tones.
A reverse burst is transmitted when the push-to-talk switch is released and also detected
when calls are received. It is a 180-degree phase reversal for a period of time determined
by the tone frequency, and it eliminates the squelch tail (noise burst) in the receiving radio.
Both the transmitting and receiving radio must be equipped with this feature for it to be
used. The radio can be programmed to turn OFF the reverse burst feature so that the
squelch tail is not eliminated.
when calls are received. It is a 180-degree phase reversal for a period of time determined
by the tone frequency, and it eliminates the squelch tail (noise burst) in the receiving radio.
Both the transmitting and receiving radio must be equipped with this feature for it to be
used. The radio can be programmed to turn OFF the reverse burst feature so that the
squelch tail is not eliminated.
If the user would like to hear the squelch tail, then the reverse burst transmission can be
disabled by programming.
disabled by programming.
5.4.3 Digital Call Guard Squelch
Digitally Coded Squelch (DCS) uses digital data instead of subaudible tones to control the
squelch. When the push-to-talk switch is released, a turn-off code is transmitted which
eliminates the squelch tail similar to the reverse burst.
squelch. When the push-to-talk switch is released, a turn-off code is transmitted which
eliminates the squelch tail similar to the reverse burst.
5.4.4 Call Guard Disable
A programmed option lets the radio disregard any CTCSS/DCS or NAC/Talkgroup
information on the current channel. This feature is best described as a monitor mode with
no white noise. In analog it is functionally the same as turning the squelch mode to
“normal.” In digital mode it is analogous to checking the “digital squelch” box when
programming the radio. The function can be programmed to any button or the ABC toggle
switch, and the menu. The mode will stay active through channel changes (between
conventional channels) and during scan. While the feature is active the monitor icon will
be displayed.
information on the current channel. This feature is best described as a monitor mode with
no white noise. In analog it is functionally the same as turning the squelch mode to
“normal.” In digital mode it is analogous to checking the “digital squelch” box when
programming the radio. The function can be programmed to any button or the ABC toggle
switch, and the menu. The mode will stay active through channel changes (between
conventional channels) and during scan. While the feature is active the monitor icon will
be displayed.