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