Technical Manual
Installation and Operation
© SPECTRA ENGINEERING 2022 Revision 1.0.0
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1.1.1 Front Panel
1.1.1.1
Standard Front Panel
The MX940 front panel provides the user with real time status of the MX940.
Figure 1-1 MX940 Front Horizontal View
Mute / Squelch Adjustment
The squelch is used to eliminate any annoying background noise when
there are no signals present. This is pre-calibrated at the factory, to provide
the user with 5 useable settings. These can be set via the channel edit
menu.
When the Squelch is Open, the receiver's background noise can be heard
and ' RX A or B ' is lit on the front panel display. When the Squelch is
closed, the receiver remains quiet when there are no signals present but any
incoming signals will override the Squelch and will enable the TTR
function.
When CTCSS/DMR colour code is enabled the channel remains quiet until
someone transmits using the same tone/colour codes. When the
transmission ends, the channel becomes quiet again. By using different
tones\colour codes, several groups of people can share the same channel
without disturbing each other. DMR also extents this via talk groups.
NOTE: If an incoming signal is very weak and is close to the minimum
squelch level, it may become broken or “chopped” by the squelch action.
To prevent this, simply decrease the squelch to allow the signal to be heard
clearly. Alternatively, you can reduce the squelch sensitivity as described
above to block out unintentional weak signals.