Transmit Modulation Tuning; Transmit 12.5 Khz Modulation Tuning; Figure 5-5. Tx Modulation 12.5 Khz Window; Table 5-3. Transmit Modulation Tuning - Motorola CP185 Basic Service Manual

5-6
5.5.3

Transmit Modulation Tuning

There are 2 variations of Transmit Modulation Tuning, namely 12.5 kHz and 25 kHz.

5.5.3.1 Transmit 12.5 kHz Modulation Tuning

1. Under the Alignment menu, select Tx Modulation, then select Mod. 12.5 kHz

(Figure 5-5. Tx Modulation 12.5 kHz Window).

2. Press PTT Toggle. This will key up the radio at the F1.
3. Read the Modulation from the Service Monitor.
4. Change the modulation setting until the Tx deviation value lies in the range of the 12.5 kHz
channel (as shown in Table 5-3.) by using either the Left/Right arrows on the slider or Up/Down
arrows on the Working Softpot box.
5. Press PTT Toggle to dekey the radio.
6. Goto the next frequency point by clicking on the Working Softpot value and press PTT Toggle.
7. Repeat steps 3–5 for the remaining test frequencies (F2–F5).
8. Press Program to commit the softpot values into the codeplug.
9. Exit the Transmit 12.5 kHz Modulation function.
10. If 25 kHz channels are used, perform Transmit 25 kHz Modulation Tuning.
Radio Programming and Tuning: Transmitter Alignment Options

Table 5-3. Transmit Modulation Tuning

Channel Spacing (kHz)
12.5
25
Figure 5-5. Tx Modulation 12.5 kHz Window
Tuning Range (kHz)
2.25 ± 0.05
4.5 ± 0.1