Copyright 2005 ISC Technologies
9. Adjust C4 on the driver module for minimum reflected power from the power amplifier
back to the exciter.
10. Adjust C2 or C3 (depending upon the band) on each final power amplifier module for
maximum output power.
11. Adjust R52 (HIGH PWR ADJ) on the logic board for 250 watts of output power.
12. Repeat steps 3 to 11 until tuning does not effect the output power of the power ampli-
fier.
13. Check that the total dc current draw for the power amplifier is less than 21 A on the dc
ammeter, and the M-97 test set current reading for the final modules is less than 20.
14. Adjust R52 (HIGH PWR ADJ ) for the desired output power level.
15. Switch OFF the power supply, disassemble the test equipment, and connect the exciter
and power amplifier in its normal configuration.
6.2 Logic Alignment
6.2.1 Equipment
The following tools and equipment will be required to properly align the 9T97A250 RF
power amplifier.
•
Directional wattmeter, 50 ohms, 250 watts full scale, 5% accuracy.
•
Directional wattmeter, 50 ohms, 5 watts full scale, 5% accuracy.
•
50-ohm termination 250 W.
•
10 Vdc minimum voltmeter.
•
Two jumpers, 0.1 spacing (GL 270-0501).
•
DC ammeter: 25 A full scale, 2.5% accuracy.
•
3 dB attenuator, 5 watt minimum.
•
Test set: M-97.
6.2.2 Low and High Power Adjust
1. Remove JR26 or JR27 (which ever is installed) to inhibit power auto shutdown.
2. Switch the M-97 test set to low, power, or connect pin 12 to pin 15 of the DB15
connector, or install JR29.
3. Switch ON the power and key the exciter.
4. Adjust R53 (LOW PWR ADJ) on the logic board until the desired LOW power output is
obtained.
5. If the LOW power setting is not required, turn R53 fully counter clockwise.
Note
Rotating R53 (LOW PWR ADJ) clockwise, increases output power.
6. Switch the M-97 test set to “HIGH” power, or disconnect pin 12 from pin 15 of the DB15
connector, or remove JR29 if installed. Turn R52 (HIGH PWR ADJ) on the logic board until
the power amplifier’s forward output power is about 225 watts.
