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Saturday, May 30, 2020

An Amazing Catalog of Circuits from HA5KHC

HA5KHC is a club station in Budapest, Hungary.  The photo above shows a portion of their worshop.  The link below is for their really amazing collection of links to ham radio circuits. 



  1. Except they are just schematics. Any related text is missing, and no easy way to track it down.

    I am reminded of the time someone asked where they could get a tunnel diode. It turned out they'd found a schematic "on the web" but coukdn't find the tunnel diode.

    The schematic had no date, so a beginner couldn't know that tunnel diodes had great promise but with a few exceptions not much practical use. They were a novelty in hobby circles, and after about a decade stopoed appearing. I 'm not sure how available they ever were for hobbyists, but after a brief period they weren't available.

    Associated text often describes how things work. It may also have information about the parts used, or what to substitute. Coil winding information may also be in the text, or in a parts list separate from the schematic.

    In this case, some of the wchematics come from qnother site, might as well just point to it.

    But nobody points to the origin, be it a website, or a magazine article. That used to bug me about books that collected schematics, no reference and missing information.

    Books and magazines provided some level of responsibility. And helped build a foundation of knowledge. Now anyone can publish, but that doesn't mean they have value to share. Or they miss out on having a good foundation, so ideas that once were common are unknown to them.

    1. More than half of the schematics are attributed in their links by call sign or club (ex.DL5NEG, RSGB, etc.). Entering DL5NEG in Google brough up his website at the top of the listing. His name is Herbert Dingfelder. Here's the link to the project article for the 7MHz QRP transceiver that is at the top of the transceiver list on the HA5KHC site. It took all of 30 seconds to find it.


      Putting these schematics in a single list will be useful to me, at least, because I'm not looking for step-by-step recipes, I'm looking for ideas and inputs to my own design efforts. I might add that reading a schematic--from whatever source--is a great intellectual exercise.

      For instance, it's a good idea to mentally--or on paper--identify a circuit's functional blocks: "Okay, that's the Colpitts oscillator . . . wait, is he keying the power to it to send CW? Bad idea, it'll chirp. He should key the buffer instead." And so forth.

      Whoever went to the effort to put this list together (thank you, by the way) naturally assumed it would be a starting rather than ending point, and that future users would do their own legwork and therefore be better nourished intellectually than if they were spoon-fed. --Todd K7TFC

  2. Someone had a LOT of time of their hands!
    Despite the lack of source acknowledgement, credits, etc. it is still one hell of a list in one place. Amazing

  3. I agree with Grayson and Todd. And remember, the folks doing it were working FAR from their native language (Hungarian). We shouldn't be so quick to criticize the HOBBY contributions of fellow hams. If you don't like the site, you are free to NOT make use of it.

  4. Incredible compilation and will come in very handy when I'm ready to wander outside the comforts of kit-building into the home brew wilderness. Thanks for sharing! 73 Steve K7YEM


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