User's Manual

31-3MDR00HB Page 51 Maintenance
Draft
Checking the MDR’s Internal Reference Frequency
To set the MDR’s internal reference frequency, use the following procedure. Note that references to the
switch in the procedure mean the Scroll/Select switch.
F r e q u e n c y
C h a n n e l
S e t t i n g s
E x i t > >
Control Screen
M o d e V D L M O D E 2
M o d e S e t t i n g s
P o l a r i t i e s
E X I T > >
Settings Screen (First Page)
B a n d E d g e s
I P S e t t i n g s
R e f F r e q 6 7 . 0 %
E x i t < < > >
Settings Screen (Second Page)
(1) If the MDR is used in AM-Voice mode
with a frequency offset, reset the offset
to 0 kHz.
(2) Connect a high impedance frequency
counter to the front panel Reference
connector.
(3) From the Main screen, press the switch
to display the Control screen. Turn the
switch until Settings is highlighted.
Press the switch.
(4) Ensure the Settings screen is displayed.
Turn the switch until Ref Freq is
highlighted, then press the switch.
(5) With Ref Freq selected turn the switch
clockwise or anti-clockwise until the
frequency counter reads 20.950000 MHz
±10 Hz, then press the switch.
(6) Turn the switch clockwise until Exit is
highlighted, then press the switch. You
are returned to the Main screen.
(7) Disconnect the frequency counter.