Hytera MD78X - Required Test Instruments; Tuning Description; Tuning Procedures; Tuning the Radio

VHF (136MHz
–
174MHz)
Tuning Description
47
8. Tuning Description
8.1 Required Test Instruments
 Radio communication test sets: HP8921 and Aeroflex 3920
 Power supply: 15 A/30 V
 Multimeter
 Tuner software
8.2 Tuning Procedures
8.2.1
Tuning the Radio
After re-assembling the radio, you need to tune it with the Tuner software and HP8921.
The specific operations are described in the table below. After tuning the items of the current channel,
you must switch the radio to the next channel; otherwise, the adjustments will not be saved to the radio
properly.
Items Method
TX Section
Reference Oscillator Warp
1.
Connect the radio to HP8921 via the antenna connector, and set
HP8921 to TX test mode.
2. Open the Tuner software and go to “TUNE_DATA -> TX ->
Reference Oscillator Warp” in the left navigation tree. Then click
the “Transmit On” button.
3. Adjust the vernier on the Tuner until the frequency offset between
the frequency displayed on HP8921 and the frequency (Tx)
displayed on Tuner is less than or equals to ±40 Hz.
4. Click the “Save” button on Tuner to save the existing value to the
radio.
5. Click the “Transmit Off” button on Tuner.
Transmit Power Calibration
Here takes the tuning of low TX power for example.
1.
Connect the radio to HP8921 via the antenna connector, and set
HP8921 to TX test mode.
2. Open the Tuner software and go to “TUNE_DATA -> TX ->
Transmit Power Calibration” in the left navigation tree. Then