Build your own kilowatt


This message might sound as advertising, but I found a very interesting solution to get a powerful RF amplifier. “Interesting” because you actually get the parts and build it yourself, so you get the chance to exercise your electronics skills, and maybe hone them to another level. Plus, you can amaze your QSO partner when you say “I’m running 1200 wiskeys from a homebrew transistor-based amplifier”. The solution is simple enough, but with these kinds of powers you need to pay attention to every detail and execute it perfectly.

What i’m talking about is building the Motorola-designed AR347 amplifier, based on a pair of MRF154 MOSFET transistors. These babies put out well over 1KW all trough the HF band up to the 6 meter band, when powered from a solid 50V/50A power supply and driven with 10-30W. Actually the MRF157’s would be just as good, they are identical but they have more gain and need less drive power.


What you need to do first is go to Pieter Ibeilings’ webpage and see all the details and worklog, as well as results and recommandations. Then you can go to Communication Concepts and order all the parts, here’s their page: Motorola AR347 amplifier ; they ship anywhere in the world and you can pay trough Paypal. Hint: if you got scared by the price of the MRF154/7’s, just go and look for them on ebay or other sites of the kind, you might find them at 1/4 of the price.

If 1 kilowatt is too much for you, then you can look into the Motorola EB104, wich puts out around 600W but is less than half the price. And the four MRF150’s needed can also be found on ebay for much cheaper.

Good luck with the build, 73’s !