8
Operation
Before attempting operation:
1. This amplifier is optimized for 50-ohm loads. Be sure your antenna system SWR
is as low as possible. As SWR increases from 1:1, either heat or distortion will
increase.
2. Be sure your antenna system, including any switches, baluns, matching circuits,
or lighting protection devices, are in good condition and will safely handle high
power.
3. Connectors, cables, and antennas must not have loose connections or
insulation failure issues.
4. Your exciter must be adjustable to significantly less than 100 watts output. Start
at 50 watts maximum drive power and increase or decrease drive to reach
desired power. Do not exceed 25 amperes or 600 watts output, and do not drive
into non-linearity on SSB. A trapezoid scope pattern is recommended for drive
adjustment. Overdriving results in an excessively wide signal, and overdriving
can damage the amplifier.
5. Power mains should be reasonably stable and match power supply voltage
wiring.
6. The low pass filters cut off just above the traditional primary amateur bands. A
primary band’s filter is used on the next lower WARC band. For example, the
20-meter low pass filter is used on 30 meters. Some radios do not supply
enough band data to know the exact band. With these radios, amplifier band
data displays the
next higher
primary band above the radio’s WARC band. If
you are using such a radio, do not be alarmed if 15 meters illuminates when the
radio is on 17 meters. This is still the correct filter.
7. The amplifier will shut off with an incorrect band selection, high antenna SWR
(even for an instant), if safe thermal limits are reached, or with catastrophic
failures.
8. The ALS-706 reads peak envelope power on forward and reflected RF power
scales.
With proper installation, basic operation is straightforward:
1.) Set the bandswitch to the desired band. This happens automatically in the REM
position with a suitable radio interface cable.
2.) Set the exciter or transceiver to the desired power below 100 watts.
3.) Place the Standby switch in the Operate position.
4.) Transmit, and watching Forward Power metering, be sure power does not
exceed 600 watts on peaks.
5.) For high duty cycle modes and long transmissions, reduce the power. The
amplifier will shut down if the FETs reach the maximum safe temperature limits.
Summary of Contents for ALS-706
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