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Proper modulation AM is indicated by observing the ratio of unmodulated carrier power
to the power indicated on voice modulation peaks. This rotation should be approximately
4:1.
Never use the ALC to control the power on AM. The "ALC SET" control should be set
in the maximum clockwise position.
Drive Power Requirements
The ALS-600 requires less than 100 watts of drive to produce full output power.
Exceeding 100 watts of drive for long periods of time may cause component failures.
Exceeding 100 watts of drive for short periods will cause distortion and increase the
bandwidth of the transmitted signal.
Follow these instructions in numerical order. Consult the manual for the exciter, if
necessary.
Be sure the power supply transformer is correctly wired for your line voltage. See the
"Line Voltage Modifications" section for wiring details.
1. Set the ALS-600 front panel switches as follows:
ON-OFF to OFF
OPERATE-STANDBY to STANDBY
2. Plug the AC line cord into the proper voltage outlet.
3. Place the power switch in the ON position. The meter lamps should light and the
power supply fans and the amplifier should start.
4. Check the voltage on the power supply meter. The
ALS-600PS
voltage should be
between 55 and 65 volts at this step.
ALS-600SPS
should be between 4.9 to 5.1 volts
at this step. If the voltage is outside this range then check the line voltage with an
accurate meter and make sure the power supply primary wiring is correct.
5. Set the amplifier's frequency range switch to the same frequency as the exciter.
6. With the amplifier still in STANDBY, transmit into the expected 50 ohm RF load
with the exciter. Measure the SWR on the amplifier's SWR scale or with an external
SWR indicator.
Caution: Do not operate this amplifier at full power with an SWR above 2:1. See the
SWR Considerations section.
7. Place the amplifier in the OPERATE position. The TRANSMIT LED should light
when the exciter is keyed. With no RF drive the idling current should be less than 1
amp on the power supply meter.
