Ubitx.net provides help for constructors: Preventing catastrophes and providing guides, fixes and modifications for your µBITx. We are an information site only and not associated with HF Signals.
WARNING: As shipped, your µBITx v3 or v4 board will probably not be compliant with emission requirements. It has been found to generate spurs and harmonics. There are now simple fixes available to address these issues. Make sure you apply them prior to operating the transceiver on an antenna.
CAUTION : If you power up the µBITX without the pull-up resistor the µBITX is likely to go into CW transmit. Make sure you install the 4.7k pull up resistor on the CW key pin!
v3 Board? – There are known issues with WX brand TDA2822 chips (U1): Read this. Earlier UCI and later socketed TDA2822 are not affected. You will probably want to do the audio pop mod at least.
v4 Board? – If your audio is distorted see this article. Note that audio output is reduced over the v3 board. If you use a low impedance speaker you may need an additional amplifier module (LM386, TDA2822, etc.) to get adequate volume. The audio pop mod is not required on v4 boards.
v5 Board? – It is too early to say as yet whether this is compliant, but early indications suggest that some boards on some bands may not be fully compliant, but they are a lot closer to compliance than v3 and v4 boards. At 30dB down or more your spurs and harmonics will be in milliwatts!
SHIPPING: µBitx orders were shipping within one or two working days of being ordered, but there seem to be delays with the v5 board currently of around 2 weeks. You should receive a shipping notification through PayPal once your product has been shipped. Estimated delivery times:
EU: IndiaPost: 2-5 days DHL: 2-5 days
US: IndiaPost: 10 days DHL: 2-5 days
Asia: IndiaPost: 2-4 days DHL: 2-4 days
AU/NZ: IndiaPost:10 days DHL: 5-7 days
BITX QSO DAY: Every Sunday – 3PM & 7PM Local Time – 7277 kHz in North America, 7177 kHz elsewhere.
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.
The source code and schematic from Jack W8TEE’s FDIM talk on the Morse Code Tutor (MCT) is now available in the Files section on:
SoftwareControlledHamRadio groups.io Group.
Please note that there are still some changes that he plans to make to the code, but there are no plans to change the hardware of the MCT.
Al and Jack consider the MCT to be Open Source, subject to the MIT Open Source agreement. (This more-or-less means that you need to leave my headers in the files.)
Note that there are multiple files in the zip file and those files must all appear in the same project directory. There are also some non-standard headers used that are not part of the standard Arduino IDE. The URL for these non-standard headers are given after their #include directives in the MorseTutor.h header file. This is to be expected because the code uses the STM32F103 (“Blue Bill”) microcontroller.
This requires you to install the STM32F patch, and there are plenty of places to find help doing that. I used “Using the Arduino IDE with the STM32F” as my search in DuckDuckGo (I’m done with Google) and found plenty of entries from which to choose, including video and written guides.
Jeff N0KAI shows off what he calls his “fun build”.
Mods to his µBITx include the Nextion 4.3″ screen , a 2.5 MHz high-pass filter for BCI, a Kit Projects AGC board, and fidelity mods to the LM386 amp.
He says that the Uniden CB mic works, but its gain is a bit low, which needs to be fixed. CW, however, works fantastically apparently.
Jeff brought the RF gain control forward to the front panel on a concentric potentiometer with the AF gain control. He really likes that, but direct soldering shielded cable to the SMT potentiometer pads on the board was a recipe for disaster. Within hours, the ground pad lifted even though he was gentle as hell with it.
Jeff suggests that it would be nice to see a future revision of the Kit Projects AGC board include better solder points or even headers for all the wires, as he tacked header pins to the pads for the switch connections. He notes, however, that the AGC circuit itself works very well.
Jeff concludes by saying “This is gonna be a fun QRP rig for Field Day…”
Jack W8TEE, a keen µBITx experimenter shows off his new creation. A dummy load with a screen and microprocessor. What the?
Good for up to 70W for 10 seconds; QRP levels ’til the cows come home.
Cost: About $20.
Are any µBITx constructors planning to be in Dayton for the 2019 Hamvention? If so, this is your chance to meet the designer of the µBITx, Ashhar Farhan VU2ESE.
It is suggest that you meet him over dinner and coffee on the Thursday 16 May. Meet up outside the Holiday Inn at 7 pm.
Ashhar is bringing with him a new project that combines an SNA and SWR meter and another one that is ‘something about a raspberry’.
Hans Summers G0UPL of QRP Labs fame will also be at Dayton Hamvention. Hans says, “I will be arriving late Tuesday night. Staying in the Holiday Inn. Will look forward to catching up with you and any other BITXers or QRP Labbers!FYI I will also have with me stock of most of QRP Labs product line, which will be available at vendors’ evening on Thursday, and throughout the hamvention on Friday/Saturday/Sunday at the QRP Labs booth 6612.”
Jack W8TEE, a keen µBITx builder and co-designer of the JackAl board, is giving a presentation at FDIM (in advance of Dayton Hamvention) this year on his new Morse Tutor project. He will no doubt publish his arduino code and schematic after the talk on 16th May 2019.
He has, however, given us his Bill of Materials so that those wanted to get a jump on ordering parts could do so.
Dan MW0UZO has an interesting story to tell about building a µBITx on his website.
And a matching speaker to go with it.
Daniel Conklin says “I guess I’ve had enough fun with this radio and now it’s time to move on.”
He is selling his UBITX v3 which is built into an Apache case. It might inspire others to build their rigs into these clamshell like cases.
There is space for the mic and a battery pack to sit when the case is closed. The mic and PTT switch are mounted in an old BaoFeng mic housing and it works well.