Codan Radio MT-4E Analog and P25 Digital - Maintenance Guide - Manual (Page 40)

MAINTENANCE GUIDE | MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS
Chapter 5: Codan Radio System Testing Page 32
Receiver RF Preselector Alignment and Tuning
Tuning of the RF Preselector fi lter is typically only required when the Analog or Digital Sensitivity or
Analog Distortion do not meet published specifi cations, or when the receiver RF frequency is changed
beyond the band pass of the fi lter (typically 5 - 7 MHz in a VHF or UHF 400 MHz receiver). The UHF
700 / 800 / 900 MHz receiver RF Preselector is Full Band and does not require any tuning.
Connect the IFR 2975 and Codan Radio as shown in Figure 5-15.
Figure 5-15: Receiver RF Preselector Tuning
The RF Preselector output is a small RF cable internal in the receiver that terminates in an SMB
connector. The SMB plugs into J3 on the Receiver Mainboard. Disconnect the SMB cable from J3 and
use the SMB-BNC adapter to connect this point to the ANT input on the IFR 2975 as shown in Figure
5-16.
Figure 5-16: Receiver RF Preselector Connection
RECEIVER
NORM
SQ. DISABLE
OFF
CNTL
BUS
A D
RF N I
REF
IN
USB
FREQUENCY (MHz)
MADE IN CANADA MODEL # CODE
RF Preselector output from Receiver
to ANT input on IFR 2975
T/R port from IFR 2975 to RF IN on Rx
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
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
J3
To ANT input
on IFR 2975
RF Preselector
output