New version of uBITx

HF Signals has rolled out the new (r4) version of the PCBs.

Changes to board design

Ashhar Farhan VU2ESE has indicated the main changes to the circuit board:

1. A new, low distortion audio amplifier made from discrete transistors. This is one is optimised for head-phones and connecting to PCs for digital modes. It will continue to work with speakers as well. Builders with the earlier versions can try this audio amplifier as an outboard amplifier.

2. The audio thump issue during T/R switching has been fixed.

3. At 28 MHz, the output is about 4 watts. (this involves a single capacitor change from the earlier PCB –  C81 was changed to 470pf – this is located on the base of Q90 being the first driver stage).

4.  ‘Jumper’ points have been included on the board to make it easier to add interesting stuff like CW filters or S meters to the board. There are a large number of test points now to help you debug and understand the board.

All in all, the changes are ‘backward compatible’ . That is, you can hack these changes to the previous boards to get in the new functionality.   Ashhar Farhan (the designer of the µBITx) has updated the circuit diargrams on

Note that the earlier production board’s circuit diagram has moved to:

In a separate post VU2ESE has indicated that the Nano will be socketed (on the reverse side of the Raduino board).   This is a bonus, as many constructors have brought their nano to an abrupt end by accident, and it can be difficult to remove the nano from the Raduino.

Price increase

The bad news is that HF Signals has had to bump up the price of the board by US$20.  Ashhar’s personal ambition was to keep the price inside of US$100.  As constructors will be aware, the release price was in fact US$109 (including standard shipping).

The new boards cost $129 USD with shipping. $139 USB with the DHL shipping option.

This price rise is the result of :

  • recent changes in the Indian import duty and sales tax
  • Increasing costs to preorder parts.
  • An increased payout to the women’s collective who wind the coils, and assemble and test the boards.

The good news is that from now on, these boards will be available within a few days of order. The backlog of orders has now been dealt to.