Toroids & broadband transformer bulletins de W1FB

My initial entry into QRP was via two kits offered by Doug DeMaw W1FB (SK) 24 years ago – a small 40 meter transmitter and a 5-watt amp.

Along with the kits, Doug included a handwritten letter to me with words of encouragement for my new interest in QRP. I sometimes wonder how many others he started on a similar path, taking pen to paper in those pre-internet days before the convenience of cut and paste.

The kits contained specific instructions and diagrams but Doug also included two bulletins he wrote with instructions on how to wind the toroids and transformers contained within the kits.

Those bulletins also have info on how the number of windings were determined, permeability and other info that was nothing short of magic to me back then.

Almost a quarter of a century later, this info is still pertinent (and often misunderstood) for homebrewers:

Bulletin T-1A (Toroids) 3.7 MB pdf

Bulletin BBT-1A (Broadband Transformers) 3.7 MB pdf



  13 comments for “Toroids & broadband transformer bulletins de W1FB

  1. Mike KD5KXF
    May 16, 2012 at 10:56 am

    He sure had a way of writing and presenting subjects in a manner that I could understand. I really like his no nonsense approach, I wish there were more like him. So many RF books seem to be the author trying to prove his intelligence and some even brandish it like a weapon but Doug’s never came off like that to me and the things he shares still seem magic.

  2. Mike N5JKY
    May 16, 2012 at 11:01 am

    John, thanks for posting these historical documents!

  3. May 16, 2012 at 11:05 am

    Wahoo! Just been chewing on this stuff in our QRP group here in Central FL. This will be very helpful in our discussions. Thanks so much for sharing this resource!
    Kelly K4UPG

  4. May 16, 2012 at 11:07 am

    Yep, he was certainly an asset to the QRP community – always encouraging and never condescending. The fact that he took time to write a letter to a newbie like me speaks volumes of his character (and patience!).

  5. May 16, 2012 at 11:54 am

    Thanks John – downloading them right now and will keep them on my hard drive. I read the first one, and it’s full of useful information. Always good to have this sort of info on-hand

  6. Bob Mayo
    May 16, 2012 at 12:34 pm

    These are keepers — thanks John! I’m returning to the hobby after 40+ years QRT. I was saddened to hear Doug DeMaw was a silent key.
    Bob – W2TAC

  7. Brian Murrey
    May 16, 2012 at 2:11 pm

    Thanks John…what a great find!

  8. Ron McCurdy
    May 16, 2012 at 2:12 pm

    Thanks for the great articles. I’m sure I’ll use them often!



  9. Jerry Palsson
    May 17, 2012 at 11:49 am

    Thanks, John. I have most, if not all, of Doug’s books — and they are pure gold. –Jerry AA6KI

  10. May 17, 2012 at 12:32 pm

    Ditto on the books…one needs re-binding due to excessive page-turning and perusing over the years.

  11. Frank KA8SYV
    May 17, 2012 at 5:52 pm

    I still read W1FB’s books — sometimes for knowledge, but often just for enjoyment. His writings continue to inspire me to build and to experiment.

  12. Glen Torr
    June 5, 2012 at 2:05 am

    Thanks John,
    I loved Doug’s articles and as a 28 year old got to meet him at ARRL HQ. I was literally stumped for words, I had built his DC 80-10.
    Following a discission on QRP-L Bill Meara sent me a pre print draft of an article on Doug’s 8P6 special (Thanks a lot Bill). A photocopy (framed) has hung near all of my work places since.
    Golden Days indeed.
    Glen VK1FB

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