Hytera PD502, Service Manual, Page: 105 / 136

UHF1(400-470MHz) Tuning Description
33
8. Tuning Description
8.1
Required Test Instruments

Radio communication test sets: Aeroflex 3920 and HP8921

3A/10V power supply

Multimeter

Tuner software
8.2
Tuning Procedures
8.2.1
Tuning a Radio
After the radio is reassembled, it must be tuned via the Tuner software.
The specific operations are described in the table below.
Item Method
TX Section
Reference Oscillator
Warp
1. Connect the antenna connector of the radio with the HP8921, and set the
HP8921 to TX test mode.
2. Open the Tuner software, go to “TUNE_DATA -> TX” and double click
“Reference Oscillator Warp” from the navigation tree on the left. Then
click the “Transmit On” button.
3. Observe the frequency displayed on HP8921, and adjust the vernier on
Tuner until the frequency offset is less than or equals to 40 Hz.
4. Click the “Transmit Off” button.
5. Click the “Save” button to save your settings.
Transmit Power
Calibration
1. Connect the antenna connector of the radio with the HP8921, and set the
HP8921 to TX test mode.
2. Open the Tuner software, go to “TUNE_DATA -> TX” and double click
“Transmit Power Calibration” from the navigation tree on the left. Then
select an appropriate channel.
3. Click the “Transmit On” button.
4. Adjust the power to the required level as described below:
L
：
1.2
±
0.1 W
H
：
4.2
±
0.1 W
5. Click the “Save” button to save your settings.
Transmit-to-Deviation
1. Connect the antenna connector of the radio with the HP8921, and set the
HP8921 to TX test mode.
2. Set the HP8921 parameters as follows:
IF Filter: 230 kHz
Filter 1: <20 Hz HPF
Filter 2: <15 kHz LPF
De-Emphasis: OFF
3. Open the Tuner software, go to “TUNE_DATA -> TX” and double click
“Transmit-to-Deviation” from the navigation tree on the left. Then click the
“Transmit On” button.
4. Observe the frequency deviation displayed on the screen and adjust the
vernier on Tuner until the frequency deviation displayed on HP8921 is 5 k
±
50 Hz.
5. Click the “Transmit Off” button.