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Wednesday, January 25, 2012

Toroidal Travails II

Steve Smith sent me a good article on broadband transformers. Reading through it, it occurred to me that perhaps using a heavier gauge wire in that PA output transformer might help. So I rebuilt the FT-50-43 transformer and put it in the final. No joy -- output was still down around 1 watt. Then I tried adding two turns to the secondary (on his web page Farhan advises experimenting with the turns ratio in an effort to improve output). Again, no joy. So I went back to the FT-37-43 transformer with 12 turns on the secondary. This yields the best results so far: about 2.5 watts. Still a bit low, but for some reason, the smaller cores seem to do better. Toroidal transformer tweaking to continue... Stay tuned.

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  1. Any chance we can have link to the Steve Smith article?



  2. Hi,

    It's not my article but here's the link: http://tinyurl.com/7rcfgqd

    It appears to be something copied from W1FB's Design Notebook or one of his other books. Nevertheless, the information is still valid.

    73.......Steve Smith

  3. I have one of those el-cheapo Ramsey qrp amps (laugh on people). Anyway, I changed out the binoc. core it comes with after messing up a repair (blew out an FET) and used stacked and glued-together toroids to make an equivalent ckt. Works fine and output is actually better. Why I do not know. Yes, small torids.


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