Northern Airborne Technology THxxx - Manual (Page 102)

Tac/Com Control Head Manual SM06 Rev. 4.10
approximately 90 channels/second. It takes almost half a second to provide tone or
DPL decoding, which would result in virtually useless scanning of 2 channels/second. It
is therefore recommended that when using either the NT150 or the NTX138, the tones
should be turned off to prevent slow scanning.
When Scanning is active, the front panel CHAN switch is inactive (for that radio),
because channel control is taken over by the scanning logic in the control head. This
may cause some operator confusion if the control head has acquired a channel (while
scanning) and manual channel change is attempted. No change will occur, and the
radio must be selected out of SCAN into NORM operation for manual channel changes
to work from the panel control.
If the microphone for a transceiver is keyed while the control head is scanning, the radio
will be rechannelled to the 'home' or monitor channel for transmission.
When scanning, a signal needs to be slightly stronger than during normal operation
because the time interval for detection is so short. No tones or DPL codes are taken
into account when scanning. The radio will stop on any scan-designated channel that
has an RF signal present, but received audio may not be heard if the tones are
incorrectly set in the control head. To avoid any confusion, tones can be set to OFF (via
the status edit function) during scanning so that all channels will be heard.
Any channel can be designated as both a PRIORITY channel and a LIST channel within
the 4 banks of 32 channels supported by NAT NT-series transceivers. The appropriate
scan flags will then appear after the channel name in the ID mode (P1, or P2, and/or
SC). Any or all of the 32 channels in a bank can be in the list for LIST SCANNING, but
only one channel each may be assigned the P1 and P2 Priority designation.
NOTE: NAT NTX138 radios provide 128 continuous channels. Therefore there can be
only one pair of priority channels selected.
When scanning is selected by the front panel mode switch, a message will be displayed
to indicate what the radio is doing. On earlier Tac/Com controls, this message was
'SCANNING', but in new software revisions, the scan mode and bank are now displayed
for better operator understanding. These messages are now as follows:
Display Scan Mode
L -SCANNING 'a' LIST SCANNING, bank 'a'
P -SCANNING 'b' PRIORITY SCANNING bank 'b'
LP-SCANNING 'c' LIST+PRIORITY SCANNING bank 'c'
Page 3-26 Jan 4, 2006
ENG-FORM: 806-0106.DOT
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