Update 18.6.21: Sadly little progress throughout March-June (waiting for Si5351's). Anyone wishing to build a V2 kit who already has a 10-pin Si5351A-B-GT is welcome to do so - just contact me on the usual email (timbly123 at ntlworld dot com). Software is done.

Update 14.5.21: Still no sign of the Si5351 parts arriving. For now I am just going to carry on boxing up my Mk 2 as a portable receiver. Current plans are to squeeze it into a Hammond RP1175C, a plastic 185x85x55mm case with a transparent lid. If this is successful it will avoid having to make a clear window for the LCD display. I also propose mounting the Discovery board closer to the panel so that the LCD display does not have to be lifted and refitted. This will require very low-profile tactile pushbuttons if they are to fit between the Discovery and the front panel. Yes, I am now experiencing delays getting hold of push buttons!!!

Update 9.4.21: I finally get round to attaching the HA8LFK bandpass filter board. 4 x M2 pillars are used (5mm pillar with washers totalling 7mm) to secure the filter board and 8 wires to the 'presel' connector. Select filter type E in the menu and away it goes :o) The overall receiver module is very compact, although the edge-mount SMA connectors are going to have to be removed to fit it into a small 'portable receiver' sized box. Work on the CAT control interface has now resumed.

Update 5.4.21: First V2 kit has shipped! The first batch is ready to go but I only have 2 Si5351s; I am still waiting for the order I placed in early Feb to arrive.

Older updates

Mk 2 Home-Brew HF SDR Receiver by Tim Howe, G0ETP

A complete, multi-mode HF + 6m SDR receiver as an easy, plug-on 'shield' for the STM32F429I Discovery Board

G0ETP V2 SDR Board connected to STM32F429I-DISC1 Discovery

Key Features compared to the V1.2 Receiver

  • Plug-on 'shield' for the STM32F429I Discovery board
  • Single board design with everything required to make a receiver, including the memory backup battery and audio amplifier
  • The software is branched from the V1.2 design and therefore the look & feel, plus all all functions are pretty much identical
  • Provision has been made for the direct connection of an HA8LFK bandpass filter board
  • Pin mapping of the ARM device has been completely redone. There is now access to 2 serial ports (UARTS)
  • Full CAT control via one of the UART interfaces will be implemented shortly
  • As a result of the new pin mapping, new features (including CAT) will eventually be available for builds using the V1.2 PCB but will require some rewiring
  • This project still requires soldering of 0603-size SMD components and a couple of fine-pitched ICs. It now includes a QFN-20 RF IC which is not too difficult with the correct soldering technique.

    Notes/advice on QFN soldering.

    Kits will be available soon - watch this space.


    Screen-Dumps Illustrating the User Interface

    G0ETP V2 SDR - 40m CW G0ETP V2 SDR - 60m SSB G0ETP V2 SDR - 20m PSK31 decoding G0ETP V2 SDR - ARRL CW Contest 21-2-2021 12:05UTC

    Additional Pictures of the Assembly

    V2 Receiver PCB - Component Side View: G0ETP V2 SDR Board - Top View V2 Receiver PCB - Underside View showing connectors that mate with the STM32 board: G0ETP V2 SDR Board - Bottom View V2 Receiver board attached to the STM32 Discovery: G0ETP V2 SDR Assembly - Edge View Early picture of V2 Receiver in operation: G0ETP STM32 HF SDR Rx V2 working for the first time

    The PCB can be seen here


    Now with the 7-band preselector filter fitted:

    G0ETP STM32 HF SDR Rx V2 assembly with HA8LFK filter board

    Video clips

    Video 1: Sample of 80m SSB, 26.2.2021

    Video 2: Tuning around 20m SSB + using the notch filters, 7.3.2021


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    Last updated: 18.6.2021