sunair RT-9000C, Operation And Maintenance Manual

Page: 314 / 393

Document No. 8128000560
Software Revision – N1B (07 Oct 04)
7-82
RT-9000 B
7.3.4.7.2 Receiving an ALL CALL
To receive an ALE ALL CALL, the RT-9000 B must currently be in ALE Receive (‘RX-ALE’) mode and
scanning. The Channel Group currently selected must contain, as a minimum, the same frequency being
used by the Initiating Station to transmit the ALL CALL.
A better practice would be to have the selected Channel Group contain all of the same frequencies being
used by the other Network stations. This suggestion is based on the fact that prevailing signal propagation
conditions might require the ALL CALL be re-transmitted on more than one frequency to reach all intended
Network stations. Network stations must be prepared to use alternate frequencies.
The Operational Display shown in Figure 7.3.4.33 indicates the following information: 1) Operating frequency
and Channel Number, 2) ‘AC’ = an ALL CALL is being received, 3) ‘SUN1’ = station CALL ID of station
transmitting the ALL CALL, and 4) ‘E’ = Link Quality Analysis (LQA) value of the received frequency. The
table shown in Figure 7.3.4.18 gives Displayed Link Quality Analysis (LQA) Value vs. SINAD conversion
values.
Figure 7.3.4.33 ALE ‘ALL CALL’ – Receiving Station Display
At the conclusion of the ALL CALL broadcast, the RT-9000 B will remain on the frequency (Channel) and
allow the Initiating Station to send further messages. If no message is received within 30 seconds, the RT-
9000 B will resume Receiver scanning. The Operational Display will continue to indicate the last ALL CALL
transmission information until more recent ALE activity overwrites it or the operator leaves ALE mode.
7.3.4.8 BREAK LINK PROCESS
From time to time it may be necessary to break a Link with another station, particularly if it is unmanned. This
allows both stations to abandon the current Link and resume other operations. Either linked station may
initiate the Break Link action.
Depressing any key selection on the Feature Menu Display shown in Figure 7.3.4.34 will cause the RT-
9000 B to transmit a “Link Terminate” message and achieve this result.
If an RT-9000 B -equipped station receives a “Link Terminate” message, it will take the appropriate action and
resume Receiver scanning.
Figure 7.3.4.34 ALE Break Link Keys
TX-ALE RX-ALE MORE END
RCV MHZ
FUNCTION/
STATUS
CH 00 9.16717
AC SUN1 E
METER
S3 S6 S9 +20 +40 +60
20 60 100 150 FWD