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Tuesday, January 12, 2010

AA1TJ: Reggies Rule! Diode Amps! QRP to the Max!



Whenever I find myself in need of some radio-inspiration, an e-mail from Mike, AA1TJ, seems to pop up in my inbox. This morning's message and the associated video (above) were especially inspirational. Mike was e-mailing Steve, WA1HFF.

Hi Steve,
Thanks for the message and the great QSO! I was running my one transistor transceiver that I call the Reggie. You can read about it on my webpage at

http://mjrainey.googlepages.com/reggie

My antenna is nothing to write home about; just an end-fed half-wave wire bent into an "EL" at 35 feet.

I've made just over 240 contacts with my Reggie in a little more than a year's time; working 19 states. My best (and only) real DX was the Bahamas. All of these contacts were made with no receiver gain on this end; just a pair of diodes fed by a one-transistor BFO, and onto the headphones.

A couple of fellows have built their own Reggies, so you might run into one on 80m now and then. I've made three Reggie to Reggie QSOs thus far.

Steve, last night I was trying something new; I ran a loudspeaker from an audio amplifer connected to my Reggie. What's unusual is that my audio amplifer was made from three, common power supply rectifiers (1N5401's). I'm not kidding! It's a nearly forgotten circuit from 1954 that I (re)stumbled upon a couple of weeks ago. It uses the phenomenon of PN junction charge-storage to produce amplification.

Last week I used two diode gain stages for a total power gain of 48dB to drive my headphones. Yesterday, I added a third diode gain-stage and connected it to a loudspeaker for shack-filling audio volume.

I made a video of last night's setup (the same setup I worked you with). You can see it at

http://www.youtube.com/watch?v=3DA07A6BLDg

Thanks again for the nice contact last night, Steve. You were armchair copy here! :o)

Best wishes,
Mike, AA1TJ

Here's a question for Mike: Can you build that kind of amplifier with homebrew point-contact diodes? If so, you'd be opening up the possibility of a homebrew solid state receiver with homebrew solid state devices. Oh man, this stuff makes me feel like such an APPLIANCE OPERATOR.

3 comments:

  1. Hi, the image is not available on this post either.

    Posts older than this and the previous one are okay.

    73 de Graham G3ZOD FISTS #8385
    http://www.fists.co.uk

    ReplyDelete
  2. Graham: I can see it here. It may be the settings on your computer. In any case the image is just the video so you should be able to watch by clicking on the video link in Mik'e message. Hope this helps. 73 Bill

    ReplyDelete
  3. Bill, aha, you're right - it's a Flash object and not a picture. I have Flash turned off on my computer (causes it to crash).

    Thanks - I'll head back under my stone now HI.

    73 de Graham G3ZOD FISTS #8385
    http://www.fists.co.uk

    ReplyDelete

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