User's Manual

RHOTHETA User Manual RT-800
Page 25 of 78
In order to interrupt the actual reception press key
Esc
(the system is continuing with next
monitoring frequency).
Active reception will be interrupted after 30 sec for a short moment in order to examine the
other monitoring frequencies (safety function). If this feature is not desired, press key
Ok
.
The active receiving frequency will be overtaken as the main frequency. Thus, interruptions
are shortened considerably, for the main frequency is monitored now with highest priority (see
also 5.2.1).
5.2.1 Timing of normal Monitoring Operation
The main frequency
(here channel 16) is
monitored with
highest priority. The
duration of the
monitoring cycles
may be extended, if receiving signals on the monitoring frequencies (also by misadjustment of
the squelch level).
5.2.2 Timing Monitoring with selected Cospas-Sarsat Main Frequency
The main frequency adjusted
to a Cospas-Sarsat-Fequency,
the timing cycle will be
changed automatically in order
to catch the short pulse
(duration of pulse ca.
400 msec, every 50 sec). Additionally the Cospas-Sarsat-Scanning is activated.
5.2.3 Monitoring operation with filtering of Emergency Transmitters: ID-Only
In order to activate the emergency transmitter filtering function see 6.4.
Signals transmitted by emergency transmitters (PLB/ELT/EPIRB) are modulated with a typical
sweeping tone. When surveilling, in order to exclude false alarms caused by disturbing
signals or by nonauthorized radio communication, the function "emergency transmitter filtering
ID-Only" may be called up. Once activated, all radio signals without the prescribed sweeping
tone for emergency transmitters will be suppressed. Alert will be triggered, if a modulated
emergency signal is recognized.
WARNING: For very weak signals recognition of modulation may take a certain time.
Releasing an alarm can be delayed in this case.
Fig. 12 Example: Timing normal monitoring
Fig. 13 Example: Timing Cospas-Sarsat