06
Appendix H: Viavi CX300 Tests
MAINTENANCE GUIDE | MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS
SYSTEM REGULATOR TESTING
System Voltage Testing
The first stage of testing a Zetron MT-4E radio system is to perform a basic system check on the supply and
regulated voltages. The System Regulator module is designed with a convenient and easy test point built into
the front panel. This test point allows a technician access to the DC supply and regulated voltages. Simply
connect a standard Digital Volt Meter (DVM) to the METER jacks on the front panel of the System Regulator as
shown in Figure H-2.
Figure H-2: System Regulator Voltage Testing
The FUNCTION rotary switch on the front panel of the System Regulator will allow you to test various points in the
radio system. Following is a list of System Regulator rotary switch positions, the functions they measure and the
parameters measured:
1
Supply Voltage
+10 Vdc to +17 Vdc (+13�8 Vdc nominal)
2
+9.5 Volts Reg9.5 Vdc (± 0.1 Vdc)
3
Rx A Audio
Receiver A Audio (NOT Rx Balanced Output)
4
Rx A Carrier Strength 0 Vdc to +5.0 Vdc based on received signal strength
(0 Vdc is a low RF signal level, +5.0 Vdc is high)
5
Rx B Audio
Receiver B Audio (NOT Rx Balanced Output)
6
Rx B Carrier Strength 0 Vdc to +5.0 Vdc based on received signal strength
(0 Vdc is a low RF signal level, +5.0 Vdc is high)
CANCEL
ms
A
A
mA
X
A
M
N
I
M
X
A
M
N
I
M
D
L
O
H
D
L
O
H
L
E
R L
E
R
RANGE
RANGE
Hz
Hz %
% ms
B
dB
d
B
dB
d
c
d
+
c
a
c
d
+
c
a
c
d
+
c
a
c
d
+
c
a
c
d
+
c
a
c
d
+
c
a
c
d
+
c
a
c
d
+
c
a
F
F
mA
S
nS
n
A
A
mA
mA
mV
mV
V
V
mV
mV
V
V
OFF
OFF
C
C
A
A
A
A
AA
M
O
C M
O
C
VV
TEMPERATURE
TEMPERATURE
A
mA
m
AA
AutoHOLD
LOGGING
SAVE
FAST MN MX
SETUP
YES
NO
DIGITAL MULTIMETER
CLEAR MEM
VIEW
DC
TRANSMITTER
CNTL
BUS
MIC
A D
RF OUT
ANALOG
NORM
DIGITAL
OFF
KEY TX
MIC MODE
REF
IN
USB
FREQUENCY (MHz)
MADE IN CANADA
MODEL # CODE
RECEIVER
NORM
SQ. DISABLE
OFF
CNTL
BUS
A D
RF I N
REF
IN
USB
FREQUENCY (MHz)
MADE IN CANADA
MODEL # CODE
VOL
SYSTEM REGULATOR
METER
+
-
MADE IN CANADA
ON
OFF
SPKR
INT
EXT
EXT
SPKR
OFF
POWER
ON
2
1
5
4
3
6
7
8
11
10
9
FUNCTION
12
REPEATER
CONTROL
RX B
TX B
RX A
TX A
PULL DOWN
TO REMOVE
9
5
3
7
11
15
9
13
3
7
11
15
SWITCH A
SWITCH B
Enter the Supply Voltage and +9.5 Volts Regulated values on the MT-4E Test Sheet. Inject a -100 dBm carrier
signal into the Receiver and record the RSSI Voltage on the MT-4E Test Sheet. Enter the Date, Firmware Versions
and Serial numbers of the Receivers and Transmitters on the MT-4E Test Sheet. The Firmware Version and Serial
Number can be found by connecting the RSS and clicking on Rx ID or Tx ID. The Serial Numbers can also be
found on the side of the modules.
The standby current draw of the radio system should be measured for battery / solar powered systems.
Connect an ammeter to the power input line and measure the standby current draw and transmit current draw
of the system. Enter the Standby Current Draw and Transmit Current Draw readings on the MT-4E Test Sheet. The
maximum standby and transmit current draw is dependent on the radio system (number and class of receivers,
transmitter output power, amplifiers, auxiliary equipment, etc.).
