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Wednesday, January 28, 2009

My ET-1 / FETer (Transceiver Made with One FET)

Magnificent, don't you think? This is my version of the ET-1 or FETer. It is an HF transceiver using only one active device -- a single MPF-102 Field Effect Transistor. I didn't have a 4 pole Double Throw switch in the junkbox, but I did have a 4PDT relay, so I used the relay. So far I have only built the receiver. It is working nicely. I was listening to German and Polish stations on 80 meter CW this morning.

I had always wanted to build W2UW's ET-1... I've been reading in "Empire of the Air" the inspiring account of Armstrong's invention of the regen receiver... Then, along came SPRAT 137 and G3XBM's FETer. I could no longer resist. Solder was melted.

It is great fun to listen to 80 meters and realize that the only thing between you and the ether is one small FET (you can see mine standing proudly atop the relay!) . Its a lot like using a crystal receiver. That one FET is serving simultaneously as an RF amplifier, mixer and BFO!

On to the transmitter! Thanks to OM Armstrong, to Glen (W2UW), and to Roger (G3XBM).


  1. This is such a cool project! I'm building a sidetone oscillator based on a QRP rig from the April 2006 QST. I'm using Argo and Hamscope to check out the signal. Lots of distortion now, hope I can get it sorted out.

  2. Good stuff Bill.

    Chris G3XIZ has just built one too and he has been received here at RST229 today and RST339 in Kent already.

    W2UW tells me he has had 451 QSOs with his 40m original, inspiring, version called the FET-1 (BTW not the ET-1) all over Eastern USA and Canada. It is truly fantastic that something this simple can be such an effective little transceiver.

    Roger G3XBM

  3. Hello all,

    A new design from Joan, EA3FXF is available here:

    SAP means "sueƱo del avaro perezoso", in English
    "dream of lazy greedy".

    This time the text is in Spanish, but the schematics
    worth a look. The transceiver is a super-hetereodine
    with a IF of 15MHz and a VXO in 22.118.
    Both crystal are common computer crystals.

    SAP is based in a NE602 used in a bi-directional mode.
    There are two units functioning very well.


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