Tuneup
Deviation and squelch thresholds
28
August 2004
© Tait Electronics Ltd
Recommended ranges and defaults are:
■
Selcall: 40 to 80% (default 60%)
■
DTMF: 40 to 80% (default 60%)
■
DCS: 10 to 25% (default 15%)
■
CTCSS: 10 to 25 % (default 12%)
■
FFSK (1200 baud modem): 40 to 80% (default 60%)
4.2
Squelch and Signalling Thresholds tab
Squelch Detect
Type: Noise Level
Sets the squelch mute opening points of country, city, and hard when the
squelch detect type is set to noise level. Each value can be changed from 8
to 20 dB SINAD for specific system requirements.
The default values for each are:
■
Country: 8 dB SINAD.
■
City: 12 dB SINAD.
■
Hard: 20 dB SINAD
Note
The hysteresis when the squelch detect type is set to noise level is
fixed at a preset level, approximately 2dB RF.
Opening Pt for
Squelch Detect
Type: Signal
Strength
Sets the squelch mute opening points of country, city, and hard when the
squelch detect type is set to signal strength. Each value can be changed from
-30 to -119 dBm for specific system requirements.
The default values for each are:
■
Country: -115dBm
■
City: -113dBm
■
Hard: -107dBm
Hysteresis for
Squelch Detect
Type: Signal
Strength
Sets the hysteresis of country, city, and hard when the squelch detect type is
set to signal strength. The hysteresis determines how much lower than the
opening point the mute closing point will be.
The default values for each are:
■
Country: 9dB
■
City: 8dB
■
Hard: 4dB
Each value can be changed from 2 to 20dB for specific system requirements.
However, as a guideline use a higher hysteresis value for lower opening
points, and a lower hystersis value for higher opening points.
