Specifications

using a long peak-hold wattmeter setting on voice while saying “hellooooo test one two
three four”. I adjusted the transmitter drive while sending “dits” until the peak reading
was 600 watts, or the maximum output the amplifier was capable of if I couldn’t get 600
watts out. Then I measured the key-down power and drive levels necessary to achieve
this. As Table 1 shows, the “new” ALS-600 does a good job meeting its typical power
output specifications. I also found the ALS-600 peak-reading wattmeter to be quite
accurate – within my ability to read the amplifier’s analog meter. I really couldn’t see
any difference between the ALS-600 power meter and the external digital power meter.
TABLE 1: Amplifier Power Output Measurements (external digital wattmeter)
Band Drive Key Dwn Peak SSB
160M 85 watts 500 watts 600 watts
80M 95 watts 480 watts 525 watts
40M 95 watts 500 watts 600 watts
20M 90 watts 500 watts 600 watts
17M 85 watts 500 watts 600 watts
15M 95 watts 500 watts 600 watts
12M 85 watts 500 watts 600 watts
10M 95 watts 500 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.
Alas – Nothing is Perfect
You need to be aware that the ALS-500RC Remote Control Head loads the ALS-600 RF
Power Meter, resulting in a half-power reading on the amplifier’s power meter. This is
not considered a problem by Ameritron, as the ALS-500RC is normally used when the
ALS-600 is remotely mounted and so the power meter isn’t readily visible. This is
discussed in both the ALS-600 and ALS-500RC manuals.
While the ARI-500 is a great addition to the ALS-600, there are a few things that would
improve its functionality. First, the ARI-500 could be made more convenient for remote
monitoring of your ALS-600. While you can use the ALS-500RC to provide amplifier
status, it would be nice if the ARI-500 had TX and O/L indicator LEDs so you could
monitor the amplifier’s status directly on an ARI-500 located at your operating position.
Next, the ARI-500 automatically puts your ALS-600 in OPERATE whenever your
transceiver is keyed, regardless of the OPERATE/STANDBY switch position on the
ALS-600. So you must turn the amplifier power off if you want to check your drive level
or operate your transceiver bare-foot. Therefore, an OPERATE/STANDBY switch
mounted on the ARI-500 would also be nice.
In order to address these issues, I built a very simple interface that plugs into the ARI-
500. See the supplemental article below for details.