Ameritron ALS-500M
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| Frequency | 1.5-22 MHz coverage; full output 1.8-21.6 MHz (160-15 m). 10/12 m with an optional kit |
| Bands | 160m, 80m, 40m, 30m, 20m, 17m, 15m |
| TX power | 500 W (Solid-state mobile amplifier: 500 W PEP, 400 W CW output from four rugged bipolar RF transistors (Ameritron PP-100 / Toshiba 2SC2879) in push-pull. Less than 100 W of drive gives full output.) |
| Modes | SSB, CW, Data (no-tune solid-state) |
| Weight | 3.18 kg (7 lb) |
| rf input | SO-239 (from the transceiver), 50 ohm |
| rf output | SO-239 (to the antenna), 50 ohm, through a 5-pole low-pass output filter |
| dc in | 13.8 V DC at up to 80 A peak for the PA, plus a separate 14-16 V DC at 4 A line for control and bias |
| remote | Remote ON/OFF, with the optional ALS-500RC remote-control head for out-of-the-way mounting |
| power req | Requires a 13.8 V DC electrical system delivering up to 80 A peak for the RF transistors, plus a separate 14-16 V DC at 4 A line for the control and bias circuits. Drive under 100 W gives full output. |
A genuinely compact, light (7 lb) solid-state amplifier that turns a 100-watt mobile or portable radio into 500 watts with no tuning and instant band changes, which makes it safe and easy to use while driving. It runs straight off a 13.8-volt system, has sensible load-fault and thermal protection with LED indicators, a clean five-pole output filter, a current meter, and an optional remote head for hiding the amp in a trunk. Made in the USA.
It demands a lot of 13.8-volt current (up to 80 amps peak), so it needs heavy wiring and a strong supply or alternator, plus a second control/bias line. Output is 500 watts, not a kilowatt, 10 and 12 meters need an optional kit, and with Ameritron's parent MFJ having wound down manufacturing in 2024, new units are sold from remaining stock.
The Ameritron ALS-500M is a compact, no-tune, 13.8-volt solid-state amplifier built for mobile and portable HF: about 500 watts with instant band changes in a 7-pound box, with proper protection and an optional remote head. It suits an operator who wants a real power boost in a vehicle or go-kit and can supply the heavy 13.8-volt current; base-station users who want more power and an AC supply look at the ALS-600, and tube fans at the AL-80B.
The Ameritron ALS-500M is a compact solid-state amplifier designed for mobile and portable HF operation. It is a 'no-tune' amplifier: there are no plate and load controls to adjust, band changes are instant, and there is no warm-up, so you just switch it on and talk, which is much safer than fiddling with controls while driving. It produces about 500 watts PEP (400 watts CW) from four rugged bipolar RF transistors in push-pull, and needs less than 100 watts of drive.
Its defining quality is size: at about 3.5 by 9 by 15 inches and just 7 pounds, it tucks into almost any vehicle, and an optional ALS-500RC remote head lets you mount the amplifier itself out of the way (in a trunk, say) and control it from the dash. It covers 1.5 to 22 MHz, with full output on 160 through 15 meters and 10/12 meters available via an optional kit, and a five-pole low-pass filter keeps harmonics well down. Sensible protection is built in: a Load Fault circuit bypasses the amplifier if the antenna SWR is too high or the band switch is set wrong, and a Thermal Overload circuit bypasses it if it overheats, each with its own LED, while a meter shows collector current and a low-speed fan stays silent until needed.
The one demand it makes is power: it draws up to 80 amps at 13.8 volts for the RF transistors, plus a separate 14-16 volt line at 4 amps for control and bias, so it needs heavy cabling and a strong electrical system. It is made in the USA and sells for around $1,200. Note that Ameritron's parent MFJ wound down manufacturing in 2024, so new units come from remaining stock.
It is the mobile member of Ameritron's solid-state line. For a base station with an AC supply and a bit more power, the ALS-600 is the natural step up, while the tube AL-80B offers more power for home use. Small barefoot-boost amplifiers like the Xiegu XPA125B serve QRP radios at lower power.