Fan shroud to help cool your finals

Dave K0MBT has been working to keep his power transistors cooler.  Initally he added a 80mm fan to blow across the transistors and board.

When doing ft8 he would get significant heating of the power transistors running on a 13.8v linear power supply.  The transistors would heat up enough  to make them too hot to keep his fingers against the surface.

He has, therefore, added a shroud similar to the one shown covering the stock heatsinks. It did not help that much.  He had a fairly small but 1″ tall computer heat sink, cut it in half and tapped in mounting holes. The shroud had to be redesigned to fit them but now he can only feel a very slight degree of heating wile running the FT8 tuning feature. 

This worked so well, he has added a similar heatsink to his BITx40.


Another board from Nik VK4PLN that does several things at once

Nick VK4PLN has been working on a new board that will give a few extra features to a stock uBitx and plugs into the audio loom socket.

Its an Audio board providing easy access to Audio I/O pins. (add in your own AGC board, External amplifier…)  It includes an area for adding an SSM2167 Mic Pre-amp module (with filtering for feedback and shutdown on TX).    It also includes the simple 4 component PTT POP fix. (BS170) and a switchable 200hz CW filter. (LM324) that Nick already produces as a board for purchase.
The board has a bonus “snap off” section with a 3.5MHZ BCI filter for the RX chain.

Here is a pre-view, NOTE this is a WORK-IN-PROGRESS.


G3EJS add on board including a different anti-pop mod

G3EJS has used a PIC processor to sequence the mute of the RX and change to TX.  The PIC responds to the PTT going low by muting the audio amp, and 100ms later, passing the PTT low state to the raduino.   When the PTT is released, it stops the PTT to the raduino, then 100ms later un-mutes the AF amp.   He then made a breadboard version, which resulted in a silent transition.

G3EJS then made some boards and finally integrated a number of mods onto a single circuit board.   Check out his pop mod circuit below:


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.


Display your callsign a bit longer in KD8CEC Firmware

 Jack W8TEE tells you how to make the callsign/version number appear for longer on boot up of KD8CEC firmware:
Near line 1200 in setup(), you will find code similar to:
  if (userCallsignLength > 0 && ((userCallsignLength & 0x80) == 0x80)) {
userCallsignLength = userCallsignLength & 0x7F;
printLineFromEEPRom(0, 0, 0, userCallsignLength -1, 0); //eeprom to lcd use offset (USER_CALLSIGN_DAT)
    delay(2000UL);        // Increase from 500
else {
printLineF(0, F(“uBITX v0.20”));
delay(2000UL);        // Increase from 500
The line in blue text will increase the delay time from a half second to two seconds.

New Release of KD8CEC Firmware v1.08

Ian KD8CEC has formally released version  1.08  of his firmware. This the first major release since 1.061, although there have been a number of Beta versions in between that many constructors will have donwloaded.
Some  key features in this version include:
1.Receive performance is improved compared to the original firmware or version 1.061
2.ATT function has been added to reduce RF gain (This shifts the 45Mhz IF passband down the slope of the filter giving an attenuator effect).
3.Added the ability to connect an inboard or outboard SDR unit after the 45MHz roofing filter (A low cost RTL-SDR is available that can be controlled by computer software providing a full SDR receiver)
4.Added ADC Monitoring in CAT communications
5. Supports several LCD variants including:
  • 16×02 Parallel LCD – i.e. LCD equipped with µBITX
  • the 16×02 LCD display configured to use I2C
  • 20×04 Parallel LCD with existing wiring in the µBITx
  • 20×04 LCD display configured to use I2C
  • Two 16×02 LCD displays configured to use I2C (Dual LCD mode)
6.Added extended switch support (up to 6 switches can be incorporated on your front panel to control various rig functions).
7. S Meter support – Any S-meter should be compatible.  The S-Meter will work on 2 or 4 line displays.
8.Added S-Meter Setting Assistant to uBITX Manager
9.Add recovery mode (that incorporates Factory Reset)
The pictures below show two different displays in operation on the rig:

There have been many other improvements and fixes. More information is available on Ian’s Hamskey blog.
Please see the link below for details of the release version of the software:
You can download HEX file and uBITX Manager from the link above. You can also download the source code at and see all the changes I’ve made so far.   If there is a non-critical bug in the public version, Ian will link to the new firmware from his blog.
A new version of the CEC firmware manual is anticipated shortly.

Raduino versions

Kees K5BCQ is trying to assemble a list of Raduino alternatives.  Here’s the modified version of his list that is not a mashup of hardware and firmware variations (which is a much longer list!), but simply a list of Raduino hardware options:

1) Original “Raduino” with a Nano Ver ? (base Farahan started with and probably what most uBITX units have today)
2) “RaduinoUMAX” with firmware by Mike Hagen, WA6ISP, (more I/O)
3) “Raduino Protoneer” (Arduino Zero Compatible Nano-ARM, uses SAM21 microcontroller)
4) Raduinoi2c Board from Nik VK4PLN (see
5) “Raduino Pill” by Joe, W3JDR (uses a STM32F103 “Blue Pill” microcontroller, lots more I/O)
6) “BITeensio”, this is the new one by Jim Shelton, W0EB, more info coming soon.
7) “JackAl” board  by Jack W8TEE, and Al  AC8GY – Teensy 3.6  (`$50).
8) “KB1OIQ” by KB1OIQ has I2C display, supports Keypad and voice output suitable for low/no vision operators. ??$$
9) “Alison TBD” by Alison, KB1GMX, uses the Nano and has no rotary encoder, less or no menu, more buttons. ??$$


New base firmware for uBITx under testing

Ashhar Farhan VU2ESE have created a next version of the base software after thinking hard about it. You can download it  here:

Ashhar invites you all to test it. if you are not familiar with C code or Arduino programming, it is suggested you wait for a few days until we get all the bugs sorted out. This is only for Arduino regulars.

Send any bug reports directly to Ashhar’s email box at In the subject line use the word “#ubitx40”. I will try to answer all emails but I can’t promise responses to all.

Ashhar has measured the mood of the BITX20 list and has made the call to substantially borrow from Ian KD8CEC’s code and back port it to the original ubitx code.  The new code has about 10% more lines but it is substantially more robust and useful.

The main features that Ashhar has cherry picked from Ian’s code are:

1. Keyer. You have to choose which keyer type to use, but the keying is much better and robust now. This code is a total copy/paste of Ian’s keyer. The auto-keyer (that sends out preset phrases in CW) is left out. The Iamabic A, Iambic B and the handkey sending works very well.

2. CAT control. Given the popularity of FT8, Ashhar has rewritten the CAT control by following Ian’s code but follows the ubitx coding conventions. It represents a miminal set of controls.

3. Split operation has been included.

4. Rationalised menus: the menu system is now more consistent.

5. Tuning mechanism: The accelerated tuning works, and it doesn’t jump randomly like before, nor does it work at the same speed. For very long band changes, it is recommended to use the menu option to change band.

Among the things left out was support for different types of displays, WSPR, and many other goodies. The EEPROM memory map has been kept consistent with KD8CEC’s plan. You can switch between both code bases easily.

Ashhar has kept usage of English words at a minimum.


Getting the VFO in the band when turning on the uBITx

With the manufacturer’s firmware that the uBITX ships with, you need to switch from VFO A to B in order to save the current frequency in EEPROM memory so that next time you power up it will use that last saved value. The manufacturer’s software only saves things if there is a specific event requiring something to be saved (such as changing VFOs).


JackAl is here!

Jack W8TEE and Al AC8GY have  released details of the JackAl board following FDIM (preceding Dayton Hamvention).

Friday night is a sort of Show-and-Tell at FDIM and they used that opportunity to show their JackAl board in action. The photo above shows a little more about what it is and does.

At the show, Al hooked up a noise generator to the µBITX to show how the filters work. (There are 4 preset filters for CW and 4 for SSB.) In addition, you can customise one CW and SSB filter to the bandwidth you desire. You might be able to see that the skirts are pretty steep for the filters on the scope in the background. The setting of the CW custom skirts are set differently, in that you pick a centre frequency (e.g., 700Hz in the shot below), press the encoder, and then you see this:

In this case, turning the encoder CCW increases the bandspread (i.e., the 440 red number above, although it looks orange in the photo) by simultaneously moving the skirts (480Hz and 920Hz) further apart. If you turn the encoder CW, you narrow the bandspread. Most CW users will probably center the bandpass on their favorite sidetone frequency, which centers the bandpass on that frequency.

The demo used a 5″ display, although a 7″ display is also available. The third knob on the front is for a second encoder that we use for everything from setting the CW keyer speed to adjusting the filter skirts. You can see some of the plots on the panel at the rear of the picture above for some of the board’s features (e.g., filter responses, compression, etc.) Those will be included in the documentation when the (downloadable) manual is finished.

The JackAl board has the following features:

  • 5″ or 7” touch screen 800×480 TFT color display
  • Dual VFO’s
  • RIT
  • S meter
  • RTC
  • CW keyer, 5 to 50wpm (we could go up to 100wpm, but…really?)
  • Up to 50 CW preset messages, selectable at runtime…perfect for contest messages
  • Touch screen function and control selection (e.g., band changes, RIT, mode, VFO, VFO increment, LSB/USB, etc.)
  • Automatic LSB/USB selection based on frequency (overrideable)
  • One touch frequency increment changes (1Hz to 1MHz in multiples of 10…the white underscore in the frequency window)
  • Dual encoders (frequency, features)
  • EEPROM storage of user preferences (one-click reset to “factory” defaults)
  • Uses Teensy 3.6 processor (1Mb flash @180MHz) and companion audio board
  • Support for 3 external CW push button switches (NO) for sending stored CW messages (e.g., contesting)
  • Hardware AGC using IF take-off
  • Audio AGC with adjustable threshold
  • Mic compressor with adjustable threshold
  • 8 band audio equalizer
  • Receive audio filter: 48dB/octave (8 pole equivalent DSP filters)
  • 4 CW presets (150, 300, 400, 600, [or none] Hz 3dB bandwidth) + 1 user-defined knee frequencies (at runtime!) filter
  • 4 SSB presets (1500, 1800, 2200, 3000, [or none] Hz 3dB bandwidth) + 1 user-defined knee frequencies (at runtime!) filter’
  • Variable Notch filter, encoder adjustable, use specified Q
  • 7 watt power amplifier

The board will be distributed with all (surface mounted) parts in place. The user must supply the Teensy 3.6 ($30), its supporting audio board ($15), and the 5″ ($34) or 7″ ($44) touch screen displaying (using the RA8875 controller chip,

We expect the JackAl board to sell for $50.

We may need to adjust this price as we have only received “ballpark” cost estimates for the board since we only have the Gerber files for the Beta board.

Currently, we are using less than 20% of the available flash memory (out of 1Mb) and less than 15% of the SRAM (256K), so there is plenty of memory resources available for adding “stuff”. The board also brings out a number of I/O pins to help your experimentation. With the exception of removing one SMD resistor on the µBITX board and soldering two wires to those pads, all interconnections are via existing connectors.

Our best guess is that after finishing the modified Gerber files, production, Beta testing, and writing support manuals, it will be probably two months before we begin distribution. We will announce its availability here as soon as we can. BTW, if anyone knows a high-quality PCB manufacturer who also does pick-and-place at reasonable prices, we are getting quotes and would like to know about them.