User's Manual

RHOTHETA User Manual RT-800
Page 40 of 78
6.3.4 Automatic Squelch
For bearing very short signals the correct adjustment of the squelch level is very important.
Because noise level varies by time and location, the squelch level must be adjusted
continuously.
The Auto-Squelch function ensures that the squelch level is always adjusted to a value a little
bit above the noise level. If noise level is rising, the squelch level is rising also. As soon as the
noise level drops the squelch level is adjusted accordingly.
WARNING: Because the DF-system can not determine between noise and continuous
signals, the Auto-Squelch will rise the squelch level slowly until the squelch level is above the
signal level. The result is that the signal is lost.
So, if you are bearing continuous signals, you have to deactivate the Auto-Squelch!
This is done by changing the squelch level using the Up/Down Keys at the main
window or at the squelch dialogue. The squelch marker then changes its appearance and
displays the current squelch value.
Activation:
To activate the Auto-Squelch press the function key F2 AutoSQL in the squelch dialogue
having selected the desired frequency.
In frequency bands with short signals (eg.
Cospas-Sarsat-Band) the Auto-Squelch is
activated automatically.
If the Auto-Squelch is activated the squelch
marker turns into green and instead of the
squelch level an A is displayed.
NOTE:
• During Cospas-Sarsat-Scanning the Auto-Squelch function can not be deactivated!
• The Auto-Squelch function can not be activated for the emergency frequencies of the
monitoring mode because these signals are mostly continuous signals!
Fig. 26 Auto-Squelch Marker
Squelch-Marker with
Auto-Squelch
activated