400W IRF520 RF amplifier

400W IRF520 RF amplifier. Delivers plenty of power, made from junkbox parts and random ferrites!!! It works very well, much to my surprise. I blew up quite a lot of IRF520 experimenting with it! I settled for 3 turns on the output transformer. This gives 400W at 24V. I did try to get more power at 13.8V with 4 turns, with initial success .... but the current peaks in the transistors exceeded safe limits and devices were slowly damaged, so I settled for increase in voltage to lower the current. It is intended to build a LPF/controller board to fit on top of it, then build a case for it with an internal 24V battery to make a useful portable amplifier. It works on 160m, 80m, 40m, 30m and 20m.

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