Transmitter Power. Motorola GM950 403-470 MHz, GM950, GM950 136-174 MHz, GM950 66-88MHz

UHF (403-470MHz) Tuning Procedure

1.4

1.5

Transmitter Power

The radio has two power level settings, a high power level setting, and a low power level setting.

IMPORTANT: To set the transmitter power for customer applications use the Per Radio window under the Edit menu and set the “Power 1” and “Power 2” powers to the desired values. Only if the transmitter components have been changed or the transmitter does not transmit with the power set in the Per Radio window, should the following procedure be performed.

The advanced power setting technology employed in the radio makes use of two reference power level settings along with parameters describing the circuit behaviour. To determine these parameters the RSS requires the power values measured for two different settings.

1.

2.

3.

4.

9.

10.

11.

12.

5.

6.

7.

8.

From the Service menu, select Tx Alignments.

Select RF Power to open the RF power tuning window. The window will indicate the transmit test frequencies to be used.

Select the Point 1 value of the first frequency.

Click the Toggle PTT button to key the radio. The status bar will indicate that the radio is transmitting.

Measure the transmitter power on your power meter.

Enter the measured value in the box Point 1.

Select the Point 2 value of the first frequency.

Measure the transmitter power on your power meter.

Enter the measured value in the box Point 2.

Click the Toggle PTT button to dekey the radio.

Repeat steps 3 - 10 for all test frequencies shown in the window.

Click the Program button to store the softpot values.

Reference Oscillator

Adjustment of the reference oscillator is critical for proper radio operation. Improper adjustment will not only result in poor operation, but also a misaligned radio that will interfere with other users operating on adjacent channels. For this reason, the reference oscillator should be checked every time the radio is serviced. The frequency counter used for this procedure must have a stability of

0.1ppm (or better).

1.

2.

From the Service menu, select Tx Alignments.

Select Reference Oscillator to open the reference oscillator tuning window. The tuning window will indicate the target transmit frquency.

3.

Click the Toggle PTT button to key the radio. The status bar will indicate that the radio is transmitting.

Measure the transmit frequency on your frequency counter.

4.

5.

Adjust the reference oscillator softpot in the tuning window to achieve a transmit frequency within the limits shown in table 2-2.

6.

Click the Toggle PTT button again to dekey the radio and then click the Program button to store the softpot value.

5A.2-4 Radio Tuning Procedure