TRXW - Low-cost TRX using Weaver method

A low cost (<45$) SSB transceiver using the Weaver method

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The goal of this project is to create a low cost SSB Transceiver for multiple bands based on the weaver method (also called 3rd method).

The TRXW is based on an SSB-Trx described by B.Kainka in the german ham radio magazine "CQ DL" in 1984 (see links), but modernized for the 21th century: The frequency generation is now done by a STM32F4 MCU, which can output up to 50 or 42MHz (in theory the TRX can work up to this frequency). Furthermore faster Logic ICs, low noise OPVs, better audio amplifier, and last but not least  it mostly uses (0805) SMD parts...

The (designated) features are:

  • SSB TRX for the most important ham radio short wave bands (160m up to (hopeful) 10m)
  • LSB and USB (the modulation) support
  • Display and rotary encoder for frequency input and menu
  • Open Source hardware and software
  • Cheap to build (<50$, maybe even <40$)
  • 3D printable casing
  • MCU can transmit and receive audio, so things like automatic stations are possible
  • Controllable by PC via USB (now the Serial Bus)


Schematics for Mainboard

Adobe Portable Document Format - 205.30 kB - 07/19/2018 at 18:14



Schematics for Power Amplifier and Filter Board

Adobe Portable Document Format - 120.73 kB - 07/19/2018 at 18:14



Schematics for NF Mixers and filters

Adobe Portable Document Format - 181.23 kB - 07/19/2018 at 18:14



[Work in Progress] Schematics for the Microphone

Adobe Portable Document Format - 38.88 kB - 07/19/2018 at 18:14


  • 1 × STM32F411 or STM32F401 Used as main MCU and for frequency generation
  • 3 × TL074 OPA used for audio mixer and filters
  • 3 × 4066 Analog switch used for audio RX/TX switch and mixers
  • 1 × 4027
  • 1 × LM386 or TDA2822M Audio amplifier for speaker

  • Project Update

    Jan B.07/19/2018 at 18:24 0 comments

    After I tried to fit all the components like Bandpass filters and Power Amplifiers on the mainboard PCB and i find out that they dont fit as whole on a 10x10cm PCB (this size is obtainable very cheap in China), i decided to put the filters and PA on a seperate PCB, which is connected to the Mainboard via a coax cable (for the HF signals) and a ribbon cable for the digital signals and power supply...

    A benefit of putting the PA on a seperate PCB is, that the high power HF signals are kept away from the sensitive HF mixers on the Mainboard, which should help to minimize intermodulation products...

    I've put the schematics for all PCBs on in the files section.

  • Schematics (nearly) finished

    Jan B.06/29/2018 at 12:46 0 comments

    The schematics of the Audio Board (here i even have a PCB) and the Mainboard are finished:

    You can find them in the downloads.

    On the mainboard are the (HF-) Filters and mixers, furthermore the main MCU, which also creates the sin/cos clocks. The board has connectors for Power and Antenna.

    On the Audio board are the most of the amplifiers, RX/TX switches and the (audio) low-pass filter. Here do you connect the microfone and the speaker.

    Now i will design a PCB for the mainboard, and a PCB for the microfone...

  • A bit of theory

    Jan B.06/08/2018 at 17:33 0 comments

    The TRXW is based on the Weaver method (often also called third method) invented and patented by Donald K Weaver in 1956 (see here:

    For a good tutorial how this method works see this tutorial:

    The TRXW is based on a transceiver designed by B.Kainka in 1984, see for the german original version.

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