The All-band HF Amateur Radio Transceiver: Just waiting to be modified
New releases for both variants of the W0EB/ W2CTX firmware have been recently announced by Jim W0EB. This includes the version that works with the existing Raduino configuration (but requires minor rewiring of the CW key) and the upgraded display using I2C (using the W0EB/W2CTX RadI2Cino card or your own mod).
Ron W2CTX reminds us that if list emails stop arriving you will need to go to the BITX20 Group website and click on the “UNBOUNCE” to get them started again. This can happen if your Internet Service Provider goes offline for a few hours, or your email box is full and bounces emails.
VK3DAN has a µBITx and as soon as he received it he was busy modding it for a 20×4 (2004) screen. This sort of screen is easily substituted on the Raduino, but to use the extra display space requires modding the firmware.
Dan has added band readout, his callsign, etc. It also incorporates the CW sidetone fix, CAT system and various fixes written by Ian Lee KD8CEC. This firmware version won’t work with the 16×2 (1602) screen provided with your uBITX kit. You will need to have purchased a 2004 type screen to replace your stock display. You will also need to edit ubitx_ui.ino to change the callsign to your own.
More info at http://www.vk3dan.ninja
Download site: https://github.com/vk3dan/ubitx-20×4
Rod KM6SN found that WSJT-X running on some versions of Linux would not work well with the µBITX. The problem was the Hamlib FT-817 protocol was not successfully connecting to the uBITX at startup.
For the past two weeks Rod has been working with Bill Somerville, G4WJS (developer of Hamlib) on the issues. He explained the nature of the problem, and provided CAT link protocol logic analyzer traces, and did bench testing of new Hamlib code Bill provided.
Bill took a lot of time out of his schedule to work on this, and it has borne fruit, having now identified the area that needed changes, provided modified software, and stayed with the problem through quite a few iterations of testing.
Rod and the rest of the digital mode enthusiast community will no doubt be grateful for Bill’s persistence.
The Hamlib FT-817 protocol has been modified to resolve the problem, and there should be an official WSJT-X release for Linux including this patch soon.
Details will be posted on uBITx.net when the new WSJT-X version is available.
FT8 seems to be the hot new digital mode. But the µBITx does it too! Check out the BITX20 IO Groups thread.
The news item http://ubitx.net/2018/03/11/ubitx-modders-are-hard-at-work/ has flushed out one or two further modders.
John, VK2ETA, writes:
“For my part I don’t know if it’s hard code developer or more mad hacker, but it is fun. Here is a picture of the latest addition, an L-Network ATU built in the uBitx case, driven by two servos and controlled by an Arduino mini pro linked over I2C to the Raduino.
“It is now working well (80m to 10m) but needs cleaning up, shields (just to make sure) and a nice display of SWR and Power on the LCD. More details to come.”
Ron, W7HD, was very interested in the servo control code and components and wiring as he would like to adapt this idea to handle a pair of servos for an az-el rotor for his satellite Arrow antenna, which only weighs about 1-2 pounds. Then he just needs to add a bit of code to show the actual antenna position and he’ll be all set!
Ron suggests another adaptation of this project would be to remotely tune a magnetic loop antenna. One of the problems you run into when trying to tune a loop is that your body affects the tuning.
Ashhar Farhan VU2ESE, designer of the µBITx, has posted to the BITX20 IO Group to say that there have been changes made to the wire up diagram to fix the errors. This is good news as there will be fewer mistakes made by constructors meaning more happy customers!
While many will have moved on to one or other of the other firmware versions available for the µBITx, those wanting updated factory firmware will be pleased to know that a bug fix release will be coming soon. uBITx.net will let you know when this happens.
A further comment from Ashhar suggests that he may use the PTT line as one of the keying lines (for the straight key). This will mean a change to the wire up in line with the approach taken by the W0EB software team.
Here’s what the little Skunkworks from Jim N5IB in collaboration witih W0EB and W2CTX has been up to!
Jim says he has “A wee PC board that accepts a Teensy 3.5 or 3.6 processor, then plugs into the space that would have been occupied by a NANO”.
Corresponding I/O lines are routed to maintain compatibility with the uBITX. Since the Teensy has a RTC (real time clock) there’s a spot for its backup battery.
In principle, the adapter could be used to plug in a Teensy anywhere a NANO used to live. On a stock Raduino (you would have to remove the NANO and socket the space). On an enhanced Raduino, such as the RadI2Cino (developed by N5IB/W0EB and W2CTX) it is simply a matter of inserting the plug.
The Teensy brings lots more memory, more I/O lines including lots of analogue ports, an on-card microSD slot, and of course a Real Time Clock.
The Teensy 3.5 runs on 3-6 volts, with 3.3V logic, but has 5 V tolerant digital inputs. The Teensy 3.6 also runs on 3-6 V, but its logic is 3.3V only. It is faster and has more memory than the Teensy 3.5.
Prototype boards are in hand and will be beta tested within the next few days. Firmware portability is of course the thing that must be confirmed.
Jim promises to keep us up to date.
Glenn VK3PE is attempting to flatten the power curve from the µBITx by playing with the driver and pre-driver stages.
He has completed his mockup of the PA driver stages and
The result is a very flat response: better than 1db from 3Mhz to 54MHz.
Glenn plans to mock up the finals now to see what the net impact is on the power response curve. If it is nice and flat he will replace the parts in the µBITx and we will have a solution that everybody who wants to flatten the power curve can use.
Bill Erickson asks, “Is it safe for me to use my current 13.8 v power supply on a ubitx, or do I need to pick up a 12 v 5a version?”
The answer is probably. Many constructors have been using 13.8v supplies with the µBITx and the BITx40, and quite happily over a reasonable period of time. The parts are generally rated to cope with 12v nominally, but this typically means up to around 14-16v.
There are components in the µBITx, however, that will not cope with more than 15v. Some capacitors are 16v rated. A component that is rated at a maximum voltage of 15v is the TDA2822.
Those of you with a WX version of the TDA2822 should be using a voltage regulator to reduce the voltage to 9v or less on this chip. The chip is, otherwise, bound to fail. Those with the FCI version needn’t worry so much, but may want to current limit (with a resistor) the output of the audio stage into speakers/headphones.