uBITx HD raduino bracket

Dave K0MBT has beefed up his design of the uBITx HD raduino bracket and added a two line display bracket.   He has also added an audio cable hold down. There is also a small dimensional change.

It is now a 3 part unit that can be used with or without the stock display.

Dave is offering these from his shack to yours for $15 including hardware and shipping.

Order from Ham_Made_Keys


Using two nanos to switch firmware

Martin, AJ6CL assembled his uBITx v5 and it seems to work OK.  It is completely stock, with the stock screen and the stock firmware.

He asked two questions:

Exactly what changes in the CEC Firmware v. 1.2 are required before uploading it in order for it to run properly on a stock Ver.5 uBITX?

Evan AC9TU replies, saying it depends on what you want for a display…  “I have the 3.2″ that Dr Lee had already created a full screen TFT file with the link from the web page.  That is what I would use.  This is a personal choice.  If you want bigger, then you will need to find the correct TFT file to match your display.  2.4 and 3.2 I believe are the two that Dr. Lee has programmed.”

“You do not need to compile the code if you use the correct hex file.  Use the uBITXV5 directory and read the FileNameInfo.txt file to help select the correct hex file to load into the Nano.  You will need the Hexloader program to go that route.  I believe that this is where I got the version that worked for me:

“In case you did not get it, here is the link to the Git Hub repository zip file:


“For the calibration process, I would do a search on this site to learn the how to do it.  NOTE that the CEC software does not use the same method as the stock (it does not turn on the transmitter to zerobeat wit another receiver.  For the CEC firmware I would download the Memory Manager that Dr. Lee has created to make the adjustments and save the values after a change to be able to backtrack if something goes wrong.”

For the BFO calibration I prefer to use a PC based free audio spectrum analyzer that can be downloaded from here:

I connected a mic to the input of my PC, tuned the uBITX to an open frequency with just static, and adjusted the BFO to center the noise spectra between 500 and 2500 Hz.  I then went back and re-calibrated the maser clock, then back to the BFO for a final time.

Can you upload the CEC v. 1.2  firmware to a spare arduino nano processor and  swap out the arduinos with different firmware and still expect the radio to perform normally?

Evan says “Yes, you can use a second Nano to program and keep the first as originally received. There are issues that need to be taken into consideration.

1 – The calibration data is stored on the EEPROM of the Nano, which is not saved in the CEC software. You will need to calibrate before it will work correctly, especially the BFO setting.

2 – The CEC software is different for each display, and the original software only works with the original display. That would mean that you need to change the Nano AND the display if you do not use the original display version of the CEC software.


Another Raduino board design

Rahul VU3WJM has designed a single sided PCB replacement for the Raduino in a form factor of 20X4 line LCD.

In fact, this board supports both a 2 line LCD display (1602) and a 4 line LCD display (2004).   Rahul has also added a few more electrolytics, separated the Analog  and Digital ground plain,  and the Nano module  is on the component side to make it easily plugable.  He has assumed mostly through-hole components but SMD pads have also been included for coupling and decoupling caps.

All fabrication files are being made Open Source for personal and club use only.   He asks that you verify the Gerbers before making the board!   Rahul would also welcome your feedback on any further improvements that could be made to the design.


Powering a larger Nextion screen from the raduino

If your larger (4.3″ or greater) Nextion display is flashing, you are probably overloading your Raduino 5v power supply.  This is because the Nextion does draw quite a bit of current.

Mark AJ6CU found a 7805 with a higher rating on Amazon (maybe 1.5A?). He mounted it on a heat sink attached to the rear panel (using the rear panel as a large heat sink) with a small perf board (to mount the appropriate capacitors).  He then brought in a set of 5V wires to replace the 7805 on the one on the Raduino.  This could be a helpful idea for those of you installing Nextion display units.

MVS Sarma suggested using a 78T05 as a replacement to the 7805. This is  a 3amp TO220 device and available very cheaply .   Managing the TO3  is little dìfferent compared to the TO220 on the 7805.

Preventing a computer from powering the Raduino

Doug Wilner  finally got around to putting KD8CEC’s outstanding firmware on his V3 µBITX.  When he is not using his rig for other things, he leaves it on rx on WSPR.  He finds using CAT control for band hopping is fantastic.

He did not want power over the USB cable going to the raduino when the rig is otherwise switched off, so he stripped back the insulation on the USB cable, parted the shielding, and like a B movie bomb tech, he cut the red wire.

With a little heat shrink on the cut ends, some copper foil to repair the shielding, and electrical tape to replace the outer jacket it looks good as new…from 100 yards 🙂

This may not be a revolutionary break through but Doug figured it was worth sharing with µBITX constructors.


A serial connection from your uBITx

Sascha DL5SMB has soldered some wires to D0 and D1 (RX + TX) and ground on the Raduino nano and then installed a MINI-DIN 8 socket to the uBITX like in an FT817.

“Why?” you may ask!   He is  building a  TF3LJs Magnetic Loop Controller at the moment, which communicates with the transceiver via CAT for tuning the antenna. This interface uses just these three lines. So he needed to make them talk 🙂

After a few hiccups, and a helpful suggestion from John VK2ETA, this solution has now been made to work.   The idea of using D0 and D1 connections on the Nano is to provide a separate serial feed to the Magnetic Loop Controller that is independent of the CAT signals coming out of the USB socket.   This may be a good solution for other potential use cases as well (e.g. driving automatic tuners).


(Yet another) Raduino replacement board

Jim W0EB has produced (yet another) drop-in Raduino clone, available in kit form, for anyone needing a replacement for a damaged Raduino that they are otherwise unable to repair or if they are just wanting to have a spare on hand.

It’s being offered as a bare board, a complete kit of parts INCLUDING the NANO which will be pre-programmed with Ashhar Farhan’s latest factory software from Github (Currently v4.3) or, for a slightly higher price, the kit version is being offered with the Si5351 already soldered in place and continuity checked to insure the connections are good and there are no shorts between the pins.

The new card has some extra bypassing capacitors.  The 4.7K CW pull up resistor can be directly mounted on the board (or if you are replacing an existing Raduino installation and have already wired it to your key jack you can leave it off the board).

The 7805 regulator has been mounted flat on the rear of the board with a heat sink and input dropping resistor so that it runs much cooler.

The clone is just over a centimeter wider than the original, but the display mounting holes have been kept to the exact same pattern.  A standard 16 X 2 parallel display will mount properly.  The display is not supplied with the kit to keep the cost lower as most users already have one or more on hand anyway.

The pre-programmed NANO  will be supplied with the pins loose and not installed so the user can mount it either on the front (not recommended) or on the back of the card to keep it out of the way of the display in the manner of the current factory supplied Raduino cards.

Any software that currently runs on an original Raduino will run on this card including the KD8CEC versions.  (That includes CEC’s Nextion enabled versions as well).

The construction manual, pictures of the board and ordering/availability information can be found on Jim’s website.


Nextion display and a second arduino

Ian KD8CEC has now given us part 2 of his description of the latest firmware update (v1.097).   If you have a Nextion display, and add a second arduino you can have a higher quality s-meter and multi-band signal monitor on your µBITx.

For more details go to Ian’s website at hamskey.com

The wire up diagram follows:

The second arduino echos information in one direction from the main raduino via the i2c serial channel which is faster than via serial port.  It uses a dedicated serial port to output the signal again, potentially making the sampling faster for taking signal strength readings.  It will be interesting to see what effect this has in practice.

Another Raduino Replacement – this time with a Blue Pill

Joe W3JDR is working  on a  Raduino Pill board which is a direct replacement for the stock Raduino, but with an STM32F103 processor and much more I/O. I think it hits all the points on your wish list. I released the PCB to fab a few weeks ago and am waiting for boards to arrive from China. Assuming it functions without major rework, I’ll post the CAD files and Gerbers on my web site and encourage others to develop for it. I plan to immediately mod the stock uBITX firmware to run on it, then will expand functionality to incorporate the work I’ve done with TFT displays, hi-res encoder and software S-meter & AGC. I’ve cleared my bench in anticipation of arrival and am checking the mailbox every day.