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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3 comments:

  1. AnonymousJanuary 25, 2012 at 11:48 AM

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

    thanks

    2E0CHK

    ReplyDelete
  2. Steve "Snort Rosin" Smith WB6TNLJanuary 25, 2012 at 2:17 PM

    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

    ReplyDelete
  3. XE1GXG RBBJanuary 25, 2012 at 8:55 PM

    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.

    ReplyDelete