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The MRF101 100W amplifer

This amp is based on the orginal by Jim, WA2EUJ on a 50x50mm PCB. (See the RF Power tools page for info)

VK3PE Version

Shortly after seeing this Amp design I desided I might build one, but it took some time to actually do so.

A couple of things put me off, the cost of the MRF101 (AUD$40), need for 50v supply and the seemingly impossible to get specified inductor by WURTH.

Eventually I decided to give it a go and use a more available dual inductor again by WURTH but 4.4uH. It's a smaller part and may not be capable of the full 100W but even 50 or so watts would be ok.


My PCB design was based heavily on the original but with changes to allow the two inductor types to be fitted, the original and the one I could get hold of. Maybe a hand made version would work.


This is a picture of my build which has been quite slow. I have had the PCB now for some time but it only got loaded here and there as I could get parts and time for it. (Too many other projects)

This is my PCB. Not yet tested. The temperature compensation diode is yet to be mounted on the MRF101.

Click for bigger Picture.

To go with it, and only being interested in 80, 40 & 20M I made a cut down version of the LPF found on G6ALU's web page, but designed by Ray G4TZR. The original was used in my, and many others Picastar builds.

The 3 band G4TZR LPF


More to come........