Codan MT-4E, Maintenance Manual

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MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS | MAINTENANCE GUIDE
Chapter 5: Codan Radio System Testing Page 49
Transmitter Reference Oscillator Adjustment
Connect the IFR 2975 and Codan Radio as shown in Figure 5-36.
Figure 5-36: Transmitter Reference Oscillator Testing
On the IFR 2975, recall Codan setup 10 (Tx_Ref) from your internal drive. Set the transmitter front
panel switch to KEY TX (or set the switch to NORM and key the transmitter through the RSS). The MIC
MODE switch on the front panel can be set to either Digital or Analog (this test does not make use of
the front panel switch).
In the transmitter RSS, enter the Service section and click on “Ref Oscillator”. The reference oscillator
frequency is shown as the “Target Frequency”. Enter this RF frequency into the IFR 2975. Click on
the “Key Tx” button and the transmitter will generate the reference frequency out of the RF output into
the IFR 2975.
Monitor the RF Error window on the IFR 2975. To change the reference frequency, click on the “Key
Tx” button and adjust the softpot slider in the RSS as shown in Figure 5-37.
Figure 5-37: RSS Transmitter Reference Oscillator Alignment
TRANSMITTER
CNTL
BUS
MIC RF OUT
A D
ANALOG
DIGITAL
NORM
OFF
KEY TX
MIC MODE
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
Computer running RSS
USB from
Computer to Tx
Tx RF OUT to T/R port on IFR 2975
HELP
MODE
TAB
SHIFT
+
-
.
BKSP
HOLD
RETURN
ESC ENTER
POWER
1 2
ABC
3
DEF
JKL MNO GHI
6 5 4
TUV WXYZ PQRS
9 8 7
# 0 *
VOLUME
SQUELCH
GEN T/R ANT
125 W MAX
MIC AUDIO I/O
DVM CH2 CH1 SCOPE TEST PORT
100V MAX 100V MAX 100V MAX