User's Manual

ALIGNMENT PROCEDURE SST-442
21
WARNING!
An authorized RF service technician must perform
test and alignment of the SST-442. Do not attempt
service of the SST-442 if not completely familiar with
the operation of frequency synthesized radio
operation. The SST-442 can operate in both Narrow
Band (2.5 KHz deviation) and Wide Band (5 KHz
deviation) systems.
RECOMMENDED TEST EQUIPMENT
1) 0 to +15 VDC, 2A current-limited power supply
2) RF Communications Test Set (to 470 MHz) with:
-
FM Deviation Meter
-
RF Wattmeter
-
Frequency Counter (to 470 MHz)
-
SINAD Measuring Device
3) Oscilloscope (to 20 MHz)
4) VTVM or DMM
5) RITRON PC Programming Kit
6) RITRON SST-SRVBD Test Module
RADIO PREPARATION
1) Make sure the radio battery is fully charged.
2) Install the RITRON SST-SRVBD test assembly
and serial programming cable as follows:
a) Remove the SST-442 antenna from the
radio.
b) Plug the SST-SRVBD into the 2.5 mm and
3.5 mm jacks on top of the radio.
c) Screw the SST-SRVBD antenna nut fully
into the SST-442 antenna connector.
d) Set the jumper on the SST-SRVBD
assembly to the “UHF” position.
e) Connect the serial programming cable from
the PC computer (with the RITRON PC
programming kit software installed) to the
SST-SRVBD test assembly
3) Connect the FM communications test set to the
BNC connector on the SST-SRVBD test
assembly.
4) Turn on the radio to place it in operating mode.
5) From the PC Programmer on-screen menu,
select “Tune Radio” to display the Alignment
screen.
6) Set the RF Communications Test set to the
Alignment Frequency indicated on the Alignment
screen.
7) Press the appropriate “Select” button on the
Alignment screen to make the following
adjustments:
SELECT Alignment
Frequency Transmit frequency
Mod Bal Modulation balance
Tone QC/DQC tone encode deviation
wide and narrow band
Voice Voice deviation with no tone
wide and narrow band
Voice deviation with tone
wide and narrow band
8) After you have completed alignment of the SST-
442, turn the radio off. This will remove the test
frequencies and return to operation on the
customer’s programmed frequencies.
REFERENCE FREQUENCY
1) Make sure the unit has been switched on and is
at room temperature (approximately +25
°
C)
2) Select “Frequency” from the PC Programmer
“Alignment” screen.
3) Set the RF communications test set to the
Alignment Frequency on the Alignment screen.
4) Press the “Tune” button on the Alignment screen
to activate the transmitter.
5) Transmitter frequency error should be less than
+/- 500 Hz.
6) If frequency adjustment is required, press the left
arrow on the tuning bar to lower the frequency or
the right arrow to raise the frequency.
7) Press the “Save” button to store the new
alignment setting or “Cancel” to leave setting
unchanged.