Codan Radio MT-4R - Manual (Page 51)

UG-001 Daniels MT-4R and MT-4D Radio Systems
www.danelec.com
Chapter 6: Radio System Components 43
User
Guide
SYSTEM MONITOR
The SM-3 system monitor is a plug-in module which provides voltage regulation, system metering and
audio monitoring for an MT-4 radio system. The SM-3 includes the following features:
- High current +9.5 Vdc voltage regulator with an anti-latchup hysteresis circuit.
- Front panel switch selectable meter outputs to check supply voltages, regulated voltages, etc.
- Audio amplifi er and loudspeaker.
- Relay drivers for optional antenna relays.
There are several different models of System Monitors as shown in Figure 6-6. The basic SM-3 is the
same size as a transmitter or receiver module. The System Monitor can also be purchased with 1 or 2
optional antenna relays.
Figure 6-6: System Monitors
Simplex Operation
The System Monitor has an internal jumper that is enabled when the radio system is operated in
simplex mode (simplex base station, or simplex links). The jumper connects the PTT OUT signal line to
the RX MUTE. JU12 is enabled for the A side pair, and JU13 is enabled for the B side pair of receiver
and transmitter. This jumper will cause the receiver to mute when the transmitter is keyed.
SYSTEM MONITOR
VOL
AUDIO A
B
2
1
5
4
3
6 7
8
12
11
10
9
FUNCTION
METER
+ -
PTT
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ELECTRONICS LTD.
VOL
AUDIO A
B
2
1
5
4
3
6 7
8
11
10
9
SYSTEM MONITOR
FUNCTION
METER
+ -
PTT
12
MADE IN CANADA
DANIELS
ELECTRONICS LTD.
SYSTEM MONITOR
VOL
AUDIO A
B
2
1
5
4
3
6 7
8
12
11
10
9
FUNCTION
METER
+ -
PTT
MADE IN CANADA
DANIELS
ELECTRONICS LTD.