The ALH is a grounded grid linear Amplifier developed by Ameritron using low cost A power triodes. It operates in class AB2 for SSB. I’ve just been asked to fix an ALH by a local. but can’t find a Service Manual download anywhere (a main board layout would be useful). The ALH is rated at watts CW carrier in normal CW or tune. The AL is rated at watts PEP voice, or just over watts carrier.

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I assume there are no professional repair people around. You agree not to post any material which is knowingly false, obscene, hateful, threatening, harassing or invasive of a person’s privacy.

Faulty Ameritron ALH | QRZ Forums

811 it first zl, I installed the tubes, did the meter mod, and got on the air. Because there size s little space was to the valve sockets. The suppression of the third- order harmonic is the difference between marker 3D and 4D. Multi-voltage Heavy Duty Transformer: The size of the 10 m coil has become too small due to mounting method.

My inspection yielded a burned grid resistor and a partially conductive varistor on.

The difference between this amp and a full power amp is a mere half an S-Unit! Page 1 of 1.

If the PA is not used for a long time and goes back into operationremove the fuse and let the amplifier an hour long stand idle. Who knows how long the supply of tubes will last, but, for now at least, this isn’t a problem.


Ameritron never published service manuals for any of their amplifiers so they don’t exist. I am wondering why you say the amp is awfully made.

ALH Modifications

Not close to L4 but far away on the PSU board. Assembled 12v W 3. I used servce “earth” the screw at the bottom of the anode choke. Service and User Manual. T he least IMD is produced with that power.

I’m guessing it was designed at the Christmas party and they were all drunk. The tubes are inexpensive and still, at the time of this writing, available. Never attempt to defeat this switch. G3YROAug 2, A tentative conclusion is that this AL – H does not distort the signal of the drive stage. I believe it’s asking for troubleand it is better to shorten the RF path by installing an additional 4n7 capacitor at the lower end of L4. Connect the amplifier to a dummy load and servicee for maximum ouput.

For decadesI advise to mount a resistor and fuse in series with the anode choke as flash over protection for tubesrectifiers and transformers.

Arcing is a momentary short flashover in one of the transmitter tubes. You may also like. I’d recommend this amp and I’ve owned many Check out other reviews on eHam Read full review. The energy could not leave via the high impedance of the plate circuitand so chose the shortest path via the tube.


Can you site some issues you think are not good and how it can be zervice.

Ameritron Al-811h 800w Ham Amateur Radio HF Linear Amplifier

No wonder so many people on here are advised not to get one. This item doesn’t belong on this page. The long wire to be replaced by coaxial cable RGso that the length is converted into a small capacitance in parallel with the load capacitor.

Other Ham Radio Equipment. That was not the diode I was thinking of. A unique “buck-boost” winding allows adjustment sedvice primary voltages to match a wide range of line voltages centered on and volts.

As radio amateur time srrvice free and one can modify at random time.

Faulty Ameritron AL-811H

Although sl administrator will attempt to moderate comments, it is impossible for every comment to have been moderated at any given time. After each modification the amplifier was firmly tested and plates never becames red.

I wouldn’t supersize that diode, it is a weak link for a reason as I understand it. No the meters are both OK.