Spectrum analyser tests of v5 uBITx board

Jim Sheldon W0EB has done some initial testing of the new µBITx board on his brand new spectrum analyser.   The results are CW only (so these results won’t show the impacts of any distortion in the mixers or IF bidi amplifiers that were observed with the v3 and v4 boards.

There are still some bands that would not meet most countries’ spectral purity requirements.

For a full set of graphs for each band click on the reference link below.


BITeensio card beta firmware released

Jim Sheldon W0EB has announced that the Triumvirate Skonk Worx (TSW) has published their latest “beta” 2.8″ or 3.2″ Color TFT touch screen firmware for the BITeensio controller card. This new firmware addresses the changes Farhan made to the uBITX in the release of his Version 5 transceiver board.  This board is now shipping from HF Signals.

Using the BITeensio card in combination with the new firmware means constructors will now have the capability of selecting operation with either the older V3 and V4 uBITX boards which we are calling “Legacy” boards or the new Version 5 ones via an item in the “Calibration” menu.

Depending on which type of uBITX it is installed in, the  one time calibration will be required for that uBITX board.

Calibration data is stored on the BITeensio’s Micro SD card in different locations for the 2 different versions so if you calibrate the card in a V4 (or V3) radio, and later decide to switch it to a V5 radio, you will have to again calibrate it for the V5 system. However, once that has been done, you can then swap the BITeensio back into your original “Legacy” radio, select “VL” in the calibration menu and it will recall the previously stored calibration data for that version. If it’s the same VL board you originally used for “VL” calibration, you should not have to re-calibrate the card. If, however, you install it in a different uBITX than the original one, you may have to touch up the calibration to make things sound right and operate on the right frequency.  The same is true for V5 boards.

Since both of the displays (2.8″ and 3.2″) use the same ILI-9341 controller, and have the same number of pixels, no software changes are needed to change out the display. No user action is required to switch from one to the other except to make sure they are cabled properly and this is outlined in the manual.

The operating manual for this software has been completely re-written to reflect the changes and the pictures have been changed to show the operating information in the new version.

You can find complete information on this (and other items from TSW) on their website.


V5 uBITx board in production

Ashhar Farhar reported on 6 February 2019 that HF Signals has pushed the uBITx v5 into production. An initial 100 boards had arrived so they may run out quickly (reminding us of the v3 board shortages of 2018).

Note that  HF Signals website has not yet been updated.

See the scans on https://groups.io/g/BITX20/album?id=84174.

The new Arduino firmware and the schematic can be found here:  https://github.com/afarhan/ubitx_v5/.

The direct link to the schematic is here:  https://github.com/afarhan/ubitx_v5/blob/master/ubitx_v5.pdf

The new firmware breaks backward compatibility with the previous firmware as the Intermediate Frequency is now 11.059 MHz and the relay switching is different.  Probably, is it is possible to patch the new code to switch between the two LPF relay switching schemes as well as the IF with some #define statements.

The new ‘features’ are :

  • The LM386 is back as the audio amplifier (like in the BITx40. All hail the cross-over distortion sickness!
  • The IF is now 11.059 MHz.   These 68pF crystals are easily available, with a pretty good 2.7 KHz band pass. As their frequency is away from any spur of 16 MHz and 25 MHz (the two crystal oscillators on the Raduino) there will be no spurs.
  • The relay switching scheme is different. The 30 MHz LPF is now always on, the individual LPFs for lower bands are switched in or bypassed (by default). It is easily understood in the circuit diagram
  • The CW wave-shaper uses a 1 uf capacitor in place of 0.1u, this reduces the key-clicks.
  • The circuit now uses BFR93W in the 45 Mhz IF amps, for more overall gain in the TX lineup.
  • A 470pf in the emitter degeneration of pre-driver instead of a 0.1uf gives more gain at 28 MHz than 3.5 MHz.
Reference #1
Reference #2