Dave Richards AA7EE

July 1, 2016

Georges F6DFZ’s Very Stylish Homebrew Version of The Scout Regen Receiver

Several months ago, Georges F6DFZ sent me pictures of a Manhattan project he had just completed, using Rex’s MeSQUARES, and I have waited far too long to share it with you. It began life as a copy of the Ten Tec 1253 regen, but George said that the results and usability were very poor. One thing that must be said about regens is that the ones which don’t work well are very dispiriting. However, when you come across a good design and build it well, the performance can be very satisfying indeed. Luckily, Georges didn’t let his initial regen experience put him off, and he ended up turning the project into a receiver based on the Kitchin-inspired Scout Regen. He normally uses PCB software to design custom boards for his projects, but decided to try Manhattan construction for this receiver.

I like how his project was obviously the result of considerable careful planning –

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Now this is what I call planning! (Photo courtesy of F6DFZ)

The slow motion drive came from a very old French military surplus rig. George says that it tunes very smoothly with no backlash, and has 2 ratios – 10:1 and 100:1. The operator pulls on the tuning knob to shift to the slow tuning rate –

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The ex-military slow motion drive and dial (Photo courtesy of F6DFZ)

The front end is taken from the Scout regen. Georges added an RF preamp stage. You can see the RF board and tuning capacitor in this photo. I am guessing that the polyvaricon is for fine tuning –

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Rear view of Georges’ regen receiver (Photo courtesy of F6DFZ)

A closer view of that RF board –

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Photo courtesy of F6DFZ

From above –

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Photo courtesy of F6DFZ

The AF stage in the Scout design uses an LM386 with the ubiquitous 10uF capacitor between pins 1 and 8 for a stage gain of 46dB. While offering high gain with a low component count (and a low quiescent current), this circuit configuration also introduces a lot of hiss. Georges used a more complex, and lower noise audio chain. A MAX293 device provides 8th order low-pass filtering for good audio selectivity, and feeds an LM380 AF output stage. Using a relatively low noise device such as the LM380 makes listening much more pleasant, in my experience. Both my Sproutie and Sproutie MK II regens use one, and I regularly listen to them both for hours at a time. Good filtering, such as the arrangement that Georges has used, also does a lot to reduce unnecessary static and noise that can make listening for long periods fatiguing. Here are the AF stages, located underneath the chassis –

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AF Stages underneath the chassis (Photo courtesy of F6DFZ)

Another view of the topside of the chassis –

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Photo courtesy of F6DFZ

Georges also added an S-meter, which he got from a QRP book by Doug DeMaw –

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Photo courtesy of F6DFZ

This receiver operates on 80M and 40M. The band coverage on each band is 3.48 – 4.8MHz, and 6.95 – 8.5MHz respectively. Everything was done with hand tools, and a sheet metal brake which was made from an article in QST – this was indeed an admirably home-brew project! It even has dial lights –

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A real dial – with lights! (Photo courtesy of F6DFZ)

I love how Georges fabricated his own custom chassis from sheet aluminum, and paid attention to all the mechanical aspects of the design, making sure to include a dial and slow motion drive. These are the aspects of making your own equipment that can be very time consuming but which ultimately, make the project more enjoyable to use, and helps to ensure that it will occupy pride of place in the shack for years to come.

Incidentally, Georges wrote an article that appeared in the Oct 2014 issue of QST, on a CW adapter for the Collins KWM-2A transceiver. You can view it here if you have an ARRL membership. Thank you very much to Georges for being willing to share these pictures and details of his wonderful regen. I find it very interesting to see how other people build their projects, and I know a lot of others do.

11 Comments »

  1. That is beautiful work. Thanks for publishing it.

    Comment by Robert L. Pendergast — July 1, 2016 @ 9:09 pm | Reply

    • Georges did a great job didn’t he? By the way, I’m an Inspector Morse fan too. In fact, almost anything that is set in a slightly kinder, gentler time, and which reminds me of old Blighty, is almost sure to find favor here!

      73 for now,

      Dave
      AA7EE

      Comment by AA7EE — July 2, 2016 @ 3:52 pm | Reply

  2. Radios with visual appeal and true craftsmanship have mostly disappeared from the scene over the last 3 or 4 decades. It’s nice to see you and George’s take on these mostly-forgotten qualities, where “radio” and “art” are synonymous.

    Comment by haskelltxJohn AE5X — July 1, 2016 @ 11:56 pm | Reply

    • It’s great to hear from you John. I missed your blog when it disappeared. The slice-of-life vignettes, as well as your stories and opinions on matters outside radio made for very interesting reading. Glad to see you back, via blogspot, and I have updated the blogroll.

      I went through a period of mourning for radios that relied as much on mechanical engineering as they did on the electronics inside. I have more or less come to terms with it, but it’s always good to come across a home-brewer such as Georges, who puts the time into planning his projects, and building them “the old-fashioned way”.

      Best of luck with your upcoming motorcycle trip!

      Dave
      AA7EE

      Comment by AA7EE — July 2, 2016 @ 3:43 pm | Reply

  3. That is a gorgeous piece of engineering.

    Comment by truthspew — July 2, 2016 @ 12:51 pm | Reply

  4. C’est magnifique! Awesome work, thanks for share!

    Pedro Arnaud XE1YZY

    Comment by Pedro Arnaud — July 2, 2016 @ 4:21 pm | Reply

  5. The mechanical work is truly inspiring, just beautiful. And, nice to see a post from you Dave, it’s been quite a while
    73 Mike N2HTT

    Comment by n2htt — July 3, 2016 @ 2:06 pm | Reply

    • Thanks Mike. He’s good isn’t he? I haven’t done any home-brew since The Sproutie MK II, almost a year ago. I achieved what I set out to achieve and think I’m done, for the time being.

      Dave
      AA7EE

      Comment by AA7EE — July 3, 2016 @ 3:04 pm | Reply

      • I have also achieved what I wanted to do and have started music.
        I hope you will do something similar, Dave, and not let your blog fade.

        rlp

        Comment by Robert L. Pendergast — July 3, 2016 @ 3:32 pm

  6. Very nice – I don’t recall ever seeing another hand-built radio with a slide rule dial. An inspiration.

    Jim – AF7VZ

    Comment by BrightBlueJim — July 24, 2016 @ 11:56 am | Reply


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