Northern Airborne Technology NPX138 - Manual (Page 51)

SM41 Rev. 4.00 NPX138 Panel Mount Radio Manual
• LIST Scanning
The second last space on each channel ID line indicates whether that channel is in
the scan list or not. If it displays a dash ‘-’, the channel is not in the list. If the channel
is in the list it displays the scan flag (sc). Use the channel edit mode to change the
scan list status for each channel. You may place any number of channels in the scan
list; but for effective scanning operation, you should keep the number to a minimum.
Once scanning is activated (using the front panel SCAN switch), the radio will move
through all the flagged channels in consecutive order until it detects a carrier. It will
remain on that channel until traffic stops, then wait for a 2-3 second latency period to
permit the operator to reply. If there is no further activity, the radio will continue
through the list, and then start over. When scanning is turned off, the radio resumes
normal operation on the home channel (the one set before scanning began).
During List scanning, the operator can use the front panel CHAN switch to delete
‘nuisance’ channels. If the radio locks onto a channel, and the operator does not want
to monitor that channel, he may move the CHAN switch to the left ‘-’ to temporarily
delete that channel from the scan list. That channel will remain out of the scan list
until the operator disables the scan mode (either by moving the scan switch back to
NORM or by turning off the radio).
• PRIORITY Scanning
The radio scans the home channel plus one priority channel. It will continue scanning
the priority channel if it finds an active channel.
To avoid accidental duplication, use the Status Edit mode to set the priority channel.
‘p1’ designates the priority channel; the lowest priority is the home channel. The ‘p1’
flag will appear on the last space of the ID line of the appropriate channel.
If the radio receives a transmission on the home channel, it will continue to check
‘p1’. The check during priority scan is very fast, about every 1/3 second, and will
sound like a faint tick when occurring during other reception. If there is activity on the
designated ‘p1’ channel, the radio will re-channel to that frequency, regardless of
activity on other channels.
The radio will return to the home channel 2-3 seconds after activity on the priority
channel has ceased.
• LIST+PRIORITY Scanning
In this mode, both LIST and PRIORITY features are combined, so that the radio
checks ‘list’ while still periodically testing for activity on the priority channel. In this
case, list channels have a lower priority than the home channel, and are scanned
only when there is no activity on the other two.
Nov 10, 2003 Page 3-17
ENG-FORM: 806-0105.DOT
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