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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Ameritron Alh w Ham Amateur Radio HF Linear Amplifier | eBay

The wire-wound resistor also acts as a replacement for inductor L7. Connect the amplifier to a dummy load and adjust for maximum servie. Can you site some issues you think are not good and how it can be improved.

The PA had no additional protection and had not been operational for years. I’ve just been sl to fix an ALH by a local. Therefore, a sumiere test was done with the two types. However, here are photos of the circuit boards, one for the earlier version and one for the later version.

I’ve never seen one before.

The A tubes take approximately 10 seconds to warm-up. You 811g that all comments express the views and opinions of the original author and not those of the administrator. You must sfrvice in or sign up to reply here. I wouldn’t supersize that diode, it is a weak link for a reason as I understand it. I have read and agree to the terms and conditions. For decadesI advise to mount a resistor and fuse in series with the anode choke as flash over protection for tubesrectifiers and transformers.


Reduces unwanted feedback to improve sdrvice. Show More Show Less. 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. Although the administrator will attempt to moderate comments, it is impossible for every comment to have been moderated at any given time.

Turn per band load and plate control clock and anti clockwise and watch if there is any anode or grid current. Your name or email address: I servicw TT gear in general, but their dual Z amp is about as “unserviceable” as any I’ve ever seen. Vernier Plate and Load Adjustments: By submitting a comment, you are declaring that you agree with these rules: Flashover in a tube sl an unprotected RF amplifier. On the other bandthe SWR will be high and is an internal tuner required for full ouput.

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

I’d recommend this amp and 811g owned many Check out other reviews on eHam Read full review Verified purchase: Yah bigger is better. Register for a free QRZ account. The shielding of the cable is only grounded at the side of C The suppression of the third- order harmonic is the difference between marker 3D and 4D.

K9STHAug 2, Fast Warm Up Time: You agree not to post any material which is knowingly false, obscene, hateful, threatening, harassing or invasive of a person’s privacy. Used to remove the Amplifier from the RF line while filament and plate voltages are maintained during “barefoot” operation. The inductance of the long supply wires can not be ignored. Skip to main content. The difference between this amp and a full power amp is a mere half an S-Unit! This versatile Ameritron feature allows the user to maintain optimum voltages on the tubes and other components to obtain maximum performance and life.


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.

Free Service Manuals

Test and adjust the SWR also on the other bands. These terms and conditions contain rules about posting comments. I haven’t confirmed this yet, as it’s really hard to get at the main board to test anything!

In some cases, not as easily serviceable as they could have been, but then what is? A tentative conclusion is that this AL – H does not distort the signal of the drive stage. I soldered this to the spot on the band-switch that hadn’t been soldered, and its been flawless since. My preference would be given to the latter because I have more experience with it.

Service and User Manual – Ameritron ALH – Amplifier — Download free service manuals

I’d recommend this amp and I’ve owned many Check out other reviews on eHam Read full review. Lenovo MT Service Manual. Yamaha TF1 Service Manual. That ‘s nothing compared to a deceased tubediodes, or worse a faulty transformer.

A Pi-Network tuned input matches the A tubes to 50 ohm exciters. Assembled 12v W 3. The A tubes are long life, reliable transmitting tubes.