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(15) Verify that all channels (all high power channels in MAB889) produce at least 1.0, 10.0 or 25.0
watts as appropriate for MAU0, MAU2 and MAU3
models. Verify that no channels produces more than 6.0 watts for MAU1 models.
(16) If the radio has option MAB889 (slaved RF power level) select any low power channel. Key the
radio and adjust R455 for an output power of 1.0 watt
(or other specified power setting) for MAU1 and MAU2 models. Verify that the RF power output
on all low power channels is between 0.7 and 1.4 watts.
Readjust R455 slightly if necessary. For MAU0 models, adjust R455 for an output power of 0.1
watt or some other specified power level. Verify that
RF power output on all low power channels is between 70 and 140 mW.
1.3 TO ADJUST THE REFERENCE OSCILLATOR
(1) Connect the radio antenna output to an accurate frequency counter through a suitable attenuator.
(2) Select any trasmit channel.
(3) Key the radio and adjust L151 (all models except those with 2 ppm stability) or R163 (models
with 2 ppm stability) until the exact transmit frequency (~100 Hz) apears on the counter.
(4) Check all transmit channels to verify that the correct transmit freguencies have been programed.
1.4 TO ADJUST THE DEVIATION
(1) Connect the radio antenna output to a modulation analyzer or test receiver through a suitable
attenuator
(2) Connect an audio oscilator to the mocrophone audio input through the circuit in figure C. Set the
oscillator frquency to one kHz and the output level to
800 mV RMS.
(3) Preset pots R302 (VCO MOD) and R305 (REF MOD) fully CCW.
(4) Select any transmit channel. For PL models select channel that transmit PL.
(5) Key the radio and adjust the VCO MOD pot R302 for appropriate deviation level:
Channel spacing
25 kHz
20 kHz
12.5 kHz
If + and – deviation readings differ, use only the higher reading.
(6) Change the audio oscilatror frequency to 200 Hz and maintain tha output level at 800 mV RMS.
Deviation setting
~ 4.6 kHz
~ 3.7 kHz
~ 2.3 kHz
Note