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.


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.


Ashhar Farhan VU2ESE inducted into CQ Magazine Hall of Fame

Doug AC9RZ has alerted constructors to the big news of the day – Ashhar Farhan VU2ESE, designer of the BITx series of kitset transceivers has been inducted into the CQ Amateur Radio Hall of Fame!  The announcement from CQ Magazine follows:


(Xenia, Ohio – May 18, 2018) – The CQ Amateur Radio Hall of Fame has 11 new members for 2018, CQ magazine announced today. This brings to 321 the total number of members inducted since the hall’s establishment in 2001.

The CQ Amateur Radio Hall of Fame honors those individuals, whether licensed hams or not, who have made significant contributions to amateur radio; and those amateurs who have made significant contributions either to amateur radio, to their professional careers or to some other aspect of life on our planet. The 2018 inductees (listed alphabetically) are:

  • Marlon Brando, FO5GJ (SK), iconic movie actor
  • David Brown, KC5ZTC (SK), NASA astronaut killed in 2003 Columbia disaster
  • Kalpana Chawla, KD5ESI (SK), NASA astronaut killed in 2003 Columbia disaster
  • Laurel Clark, KC5ZSU (SK), NASA astronaut killed in 2003 Columbia disaster
  • Ashhar Farhan, VU2ESE, pioneer in popularizing open-source Bit-X “semi-kits” using Arduinos for affordable QRP transceivers

  • Grady Fox, W4FRM (SK), SSB pioneer; worked on Manhattan Project during World War II and the camera for NASA’s lunar landers
  • Wendell King, ex-2ADD (SK), African-American pioneer of broadcasting and college radio
  • Fred Lloyd, AA7BQ, founder of, the most widely-accessed amateur radio website
  • Mark Pecen, KC9X/VE3QAM, wireless communication and networking pioneer, inventor, cybersecurity expert
  • Carole Perry, WB2MGP, longtime advocate for youth in amateur radio; moderator of Dayton youth forum for more than 30 years
  • Ed Westcott, W4UVS, photographer who chronicled the Manhattan Project during World War II and later helped the FBI with its investigation of the Jonestown massacre

Two new members each are also being inducted into the CQ DX and Contest Halls of Fame at the respective Dayton DX and Contest dinners. Their names will be announced separately.

CQ Communications, Inc. / 17 West John St. / Hicksville, NY 11801 USA / 516-681-2922

The world’s premier independent amateur radio publisher.

Publishers of:
CQ Amateur Radio, CQ Books, the CQ Video Library


uBITx Success stories

DougAC9RZLately I've been playing with FT8 on my µBITX. I am more interested in learning as much as I can about propagation and antenna optimization than talking to strangers most of the time. Say what you want about digital modes, they meet that requirement for me. Last night I completed a QSO with an operator in Russia 4582 miles away on 30m putting out 4.67 watts (as measured with my QRPguys dummy load/power meter). Sure I just missed the illustrious 1000mi/w but it is a personal µBITX best for me not counting WSPR which even though is only a one way mode continues to amaze me.

My very first contact with my BITX40, first HF contact at all for that matter, was with W9IMS. I'm not a race fan but they had a good strong signal and I got through. I don't collect paper but I made a quick QSL card on card stock just so I could get theirs to commemorate it.

Update: I just completed an FT8 QSO on 30m to ZL with only 4.67w out. That's 1745.33mi/w. I also hit 1508.1mi/w in the other direction a few days ago. I'm not sharing this to boast. I'm posting this as a testament to what this gem of a radio can do with a decent antenna.
BoW4GHVI'm still struggling getting audio levels right. It's hard to turn my nearby iCom 7300 down low enough to see a clean signal.
On FT8 soon
CraigW9CTWMy wife had watched me carefully collecting (inexpensive) parts to build a uBitX over many months. When she heard about Ash’s ‘elves are busy’ post,she game me the $$$ to buy one. It’s been fun, and I’m planning to try it on FT8 tonight (finished soldering the cables a couple nights ago). It’s exactly what Ashhar designed: an amazingly inexpensive transceiver that, with a little work, will soon do almost everything my FT-817 can - with a better receiver! It’s cheap, it’s fun, and I’ve learned a lot from it and from the others on this list.
TonyG0PBMI would echo the positive news story - getting my uBitx up and running on Saturday and setting up only took an evening, the 'poor audio quality' turned out to be the BFO frequency being off - easy to fix (especially if you look at the basic documentation on calibration on the HFsignals website). I reckon I'm getting around 10W out on 80m, using a long wire via a home brew L match. First contact was in Denmark so a reasonable DX from the UK, especially on low power. Sunday evening had several contacts round the UK, including a /P station on one of the Scottish islands. Best of all was the Worked All Britain net where I spoke to another radio amateur using a uBitx!!

In the process of putting a case round the radio now, I will do the PA mod to unleash it at higher frequencies.

A big Well Done to Ashhar Farhan and Co for making this radio to folks round the world at such an affordable price!!
JayWS4JMI am having a ball with mine, I get around 10 watts on 80 and 40 meters. I am making contacts up to around 700 miles from a fan dipole at 35 feet (10 meters or so). I am putting the finishing touches on my enclosure, a re-purposed Cobra 148 CB case, and am enjoying the whole experience. I am going to attempt to do Howard's mods for leveling out the power on the upper bands and add the necessary cabling for digital.

I have also uploaded the KD8CEC firmware, and must say it is a pleasure to use. Thanks to Ian for his hard work!
DanW2DLC I have been making contacts with special events stations and DX on 40 meters SSB. My first contact was the Marconi Birthday Memorial station in Cape Cod, then the Indy Speedway F1 race day station. Since I sole my FT=817 two years ago I've only been using CW with home built QRP transmitters, so it's a real treat to be able to make some voice contacts with a radio that I may not have designed and built, but at least I assembled it.
BillWA8VIH/4I haven't had a chance transmit other than CW mode into a dummy load. I want to finish my antenna analyzer before I start pumping rf into my Carolina Windom. Reception was very good but noisy with all the weather here in Florida at this time. Lightning is a major concern as my antenna is almost as high as my natural lightning rods, pine trees 60 - 90 feet tall. As a QCWA member I enjoy CW as my primary mode but really have enjoyed WSPR with my U3S. I see a lot of digital in my future.
TomAB7WTThe uBITx has been a blast! 330 FT8 QSOs in 6 weeks including 46 states and 12 countries on 4 watts or less. Using end-fed 59 ft antenna to tree. Having too much fun to see the negative......:) Looking forward to "souping up" the 2nd uBITx!
RobAG5OV My uBITX is my first HF rig. I ordered to close the deal on getting my Extra. I got my Extra 2 weeks later and got my CW up to 13wpm (5 char, random) as penance for not getting my ticket 30 years ago.

While waiting for my uBITX to arrived I read, looked up part numbers, googled what it did when I didn't understand it, ordered some extras, practiced my soldering and read some more. I ordered the SMD practice boards, a new soldering iron and some spare IRF510's and RD16's as well as some SMD kits.

uBITX arrived, I soldered it up and started the "Junkyard Dogs" thread here for my complete lack of regard for aesthetics. I fired it up and couldn't get any SSB QSO's with my EFHW, so I found the CW key memory and sent "TEST AG5OV TEST" a few times and checked the RBNs....IT LIVED, I was getting out!

Next I updated the firmware to Ian's fantastic work and soldered up a home grown EasyDigi interface and plugged it into a RPi. I've been running FT8 and WSPR almost continuously since I turned it on a couple months ago. I'm over 700 digital QSOs, 0 SSB (it'll come, no rush) and 0 CW (printed up a key, just need to wire it up). It's been, simply, fantastic. I'm so very glad I went with the uBITX as my first HF rig, the experience with both the product and the support here has been more than I could have imagined. It's what I got into ham for, to explore, to learn, to discover to get that spark in the mind of "ah ha!".

I wouldn't change a thing, even my dreaded WX2822...where I got to down convert to 12.1v instead of running at full 13.8. If I had wanted to make eleventy-seven DX SSB QSO's in the first week then I wouldn't have picked the uBITX. I don't need that, I yearn for discovery and and exploration.

I'll add that I have a 2nd uBITX still in box that I need to wire up and put across town. I'm super interested in not just digital modes, but data modes and having my own testbed with rigs across town and network access to each end will be great fun.
DaveK0MBTI got the bitx40 as an interm radio while by ubitx was still over in India.
Between the two I have made contacts with SSB in 40 US states as well as Ontario. A couple of weeks ago I put in the firmware for ft8 and have made numerous contacts in Eastern europe over 5000 miles distant.

When on the air I get good audio reports including some 5-9+10 over 1000 miles away. God has to be with us on the atmospherics of course. These radios are my first HF rigs and I am told just wait till propagation gets decent again. My antennas are dipoles made from steel electric fence wire with weed eater nylon line tied to the ends for insulators. The lead in is RG6 75 ohm used cable TV coax that I have scrounged over the years. I am sure I've made many mistakes but it does work and has not cost me much.
AllisonKB1GMXWell took it out of the box and wired up the connectors and all and having on the bench spread out.
haven't measured power in any exacting way for at 11V I see 6W at 7mhz. Receives well.

I then installed my mod for the audio amp to run it at 8V regulated. It works. Only one part
used an lm7808.

Changed the resistor on the back of the LCD from 100ohms to 330 to damp down the brightness a bit.
Adjusted pot on the back of Raduino for better contrast.
Flipped the 5V regulator around so it doesn't hang off, my case needed that bit of space for a really
good encoder.

Next step is the bias on Q70 its sitting at 1.6V way too low for good overload results. 16k resistor will fix that.

After that replace q90 with 2n2222A and then check the bias it seems to be at higher current than needed.

At this point I'll break for an order of a dozen MPSH10 and some other RF parts to try.

The case, no matter what they say the drillin and blastin is the work:
While waiting I'm working the fitment of the case and the various parts. Other things that
will need to be on the panel is the power led, some form of metering for received signal
strength and relative TX power (bargraph but not on LCD).
Mic jack, headphone, and antenna jack are on the front panel along with LCD and power
switch. Then we have audio level and rf-gain. All this goes in an area 8.x inches by 2.25 inches.
It has the potential for being cramped if I use the larger tuning encoder. The display
eats panel space too.

plodding on..
John KG5WJQ I guess I would be able to obtain the 1000mi/W award as I had contact with Fiji from the Texas/Mexico border at the Gulf Coast. But as I am fairly new (6 months) still have to learn about those things. Contact was made on 10m with FT8 in March. Before that I only had seen reception reports drom Japan and Europe. So I'm pretty pleased with my uBitx with an end-fed in the attic.
W5JXN I've been working FT8 for a few days on my shiny new uBITX tied to a homebrew G5RV set up as an inverted v. Just finished a 20m QSO with Tasmania.... thats over 9000 miles on just less than 9w! Amazing little rig!

W3JDR has been busy cooking up some interesting mods

Joe W3JDR asked on the IO Groups BITX20 list for CAD details for a board layout for the Blue Pill” STM32F103 processor.  Members quickly discovered that Joe has a blog with details of his hacks to the µBITx that would be of wider interest to constructors.


Check out  for a range of mods including:

  • audio preamp (Q70) dynamic range improvement by substitution of a resistor
  • a digital sampling S Meter
  • a slide rule type colour display for frequency
  • an amazing front panel for his µBITx
  • a high resolution optical encoder

Joe says,

“I’ve been busy behind the scenes doing a lot of things with the control system. I now have the entire app running on an STM32F103 “Blue Pill” board, which is only about $2.50 on Ebay. This gives me a 70 mHz 32 bit controller with 128K bytes of program memory.

“My software S-meter is now working quite well and only requires 2 resistors and a cap, plus some code. I’m using a separate ILI7735 display for the S-meter, both displays on the same SPI bus. The S-meter is derived from a 10kHz sample-rate of the pre-amp audio, with software peak detection. The TFT meter display has a max-hold pointer that resets every few seconds, while the main pointer is real-time. There are digital readouts on it for peak signal level in uV, dBm and S-units.

“The measurements from the S-meter will drive a digipot after the audio pre-amp to effect a feedforward AGC. Feedforward, with software calibration, should make for a very fast acting AGC without the overshoot/undershoot artifacts of feedback systems.

“I’m also using a 400 ppr optical encoder for frequency control with interrupt processing; it tunes beautifully smooth, with 1 hZ steps and software acceleration. . All of this puts a real strain on the little Nano u-controller, hence the move to the Blue Pill.

“I intend to layout a new Raduino that accepts the ‘pill’, with extra connectors for SPI and I2C busses. I developed my own tinier version of the Adafruit Si5351 board that will mount on the Raduino. I might even use a separate Si5351 for the main VFO in order to eliminate the crosstalk spurs generated in the single-chip approach. This was all moving smoothly while I was house-bound during Winter, but will slow down while the weather’s nice outside.”

Shipping paused

Several constructors had ordered their µBITx expecting a shipping notice, but hadn’t received one.

Ashhar Farhan VU2ESE confesses, “The trouble is me. I am supposed to ship an updated firmware. They are waiting for that. The boards are ready, the software was supposed to have been delivered last week.”

It turns out that family matters have intervened.  Patience folks!


An improved reverse voltage protection circuit

With four components, and the on:off switch, Bill K9HZ provides the ultimate reverse voltage and over-current protection system for your µBITx.  The fuse protects the circuit from excessive current draw – so you won’t blow your finals when you wind up the bias too far and they try to go into thermal runaway.  The relay must be powered on to power your µBITx (and the switch must be turned on).  With the series diode in place the relay cannot turn on unless the power is wired up correctly.

Upgrading the PA output transformer

JerryW0PWE notes that in the posts on boosting and/or leveling output power he saw pictures of a binocular core being used as the output transformer in place of the toroid that comes with the uBitx board.  He asks “What size is that binocular core?”

Allison plans to use the longer version of the BN43-6802 (or two BN43-302 cores end to end).

John VK2ETA says he went back to IRF510s in the finals and has used a BN43-3312 as the single 302 was getting warm on the low frequencies and he could not put more than 2/3 turns in the core.  He tried both 1/2T and 2/4T in the 3312 and settled on 2/4T due to better efficiency. The 1/2T drew too much current at 80M.

There is plenty of gain and power at 14MHz and below on 16.8V for the PA but has had to resort to a gain control for flattening the power curve despite 330pF caps in all 6 drivers emitter resistors, 22uH inductor in the base feedback of  the pre-driver,  330 pF across the primary of the finals transformer and 820ohms in the finals feedback resistors.

Nick VK4PLN uses the BN43-202 with a winding ratio of 2:4 using 0.64mm enameled CU.  His rig is outputing 20W+ on 80/40/20 using RD16HHF1.  Nick doesn’t detect any heating… Maybe it will at that power level on 10m?

His plan is to now try using:

– the MPSH10 in the pre-driver
– a single 10T bifilar wound FT50-43 for feeding the power to the RD16HHF1s
– removing the PA feedback loop
– and other pre-driver mods as per Farhans suggestions….

This appears to be the common approach on most of the RD16 amp designs out there…and Nick hopes he will get 20w+ output from 80-10m….

Bill K9HZ tried a BN61-002 and it seems to be a winner.  It doesn’t heat up at full power and it seems to be extremely wide band.


Finding a compiled Hex file for the arduino

Jack W8TEE has provided directions on how find a compiled hex file:

1. Go to your Preferences settings (File –> Preferences) and check “Set verbose output during” and check “compilation”
2. Compile the program. Do not upload as that erases all temporary files, including the hex file. In other words, just click on the
check mark icon that appears below the File menu option.
3. Scroll down the long list of output your compile generated until you see: “Linking everything together…” followed by a series of
lines with path and file names. The hex file for you program will be one of them. Just use that path name to find the hex file.

While you’re there, use a text editor to open the *.lst file. It shows a blending of C and assembler generated by the compiler. It’s an interesting way to find if one way of writing a piece of code is “better” (i.e., faster execution, or perhaps using less memory) than an alternative way.


Variable IF bandwidth from W1EAT

Tom W1EAT provides a  schematic for his mod of a variable IF bandwidth circuit for the µBITx.  The RX and TX voltages are about 12V,  so he used a resistor network to keep the applied voltage to about 1 to 9V because that is the usable range for the varicap diodes he uses.  As the voltage on the caps is reduced the higher audio frequencies are reduced until the bandwidth is probably 100Hz or so at 1 volt. The filter centre frequency is very low, 200 Hz or so with Tom’s BFO setting.

The BB112 has about 500pf capacity at 1 volt applied.

The 4.7K resistors that feed the voltage to the VVC diodes could be 10 or 20 K, or what have you, as there is very little current needed.