Specifications

Photo C: Rear panel of the ALS-600
To key the ALS-600, your transceiver’s amplifier keying output must be able to handle
12VDC at 100ma. If there is any doubt about this, use a transceiver interface buffer such
as the Ameritron ARB-704. The ARB-704, along with a transceiver-specific cable,
provides high current solid state switching capabili ty and ALC interfaces for any
amplifier.
Performance Measurement
My first tests included measuring amplifier power output and checking the amplifier’s
internal power meter against an Array Solutions PowerMaster NIST-traceable digital
peak-hold wattmeter. As Table 1 shows, the ALS-600 does a good job meeting its
typical power output specifications. I also found ALS-600 peak-reading wattmeter to be
quite accurate – within my ability to read the amplifier’s analog meter. The worst-case
discrepancy with the external digital power meter was 6%, with most readings within 1-
2%.
TABLE 1: Amplifier Power Output Measurements (external digital wattmeter)
Band Drive Key Dwn CW “Dits” Peak SSB
160M 90 watts 600 watts 630 watts 650 watts
80M 90 watts 480 watts 490 watts 500 watts
40M 90 watts 525 watts 550 watts 550 watts
20M 90 watts 600 watts 600 watts 600 watts
17M 90 watts 650 watts 610 watts 610 watts
15M 90 watts 650 watts 620 watts 600 watts
12M 90 watts 550 watts 550 watts 550 watts
10M 90 watts 560 watts 575 watts 580 watts
I also verified that the SWR protection shutdown occurs at 75 watts reflected power,
corresponding to an SWR of 2.1:1 at 600 watts. Since the amplifier protects itself at an
absolute value of 75 watts reflected power, operating into a higher SWR is possible by
simply reducing your output power. But you really should address the high SWR issue .
On the Air
Actual operation of the ALS-600 is very simple . All you have to do is set the band
switch, select “Operate”, and transmit. It is amazing how often I find that the amplifier
comes in handy, even in ra g-chewing QSOs. When conditions degrade, I just flip the