sBitx

sBitx – Developer’s Edition

The sBitx Article | Operating Manual | Circuit Diagrams and Software | Assembly Manual

Buying Options : Fully Assembled $499 | Basic Kit $299

The sBitx is a 40 watts, fully open source, high performance HF SDR transceiver with in-built popular modes like the FT8, RTTY, PSK31, etc.  HF Signals is now selling the Developers Edition for the homebrewers and the hackers who are comfortable with frequent updates and experimental branches of the software.
Fully Assembled and tested sBitx with microphone

Performance from Simplicity

Performance doesn’t have to come with expensive components. A careful application of design principles over inexpensive and readily available parts and modules like the Raspberry Pi and ordinary transistors like the 2N2222s, results in a simple radio that is powerful and yet easily understood. Easy to understand, simple circuit that allows you to modify, enhance or experiment. None of the components cost more than a few dollars. Read the detailed sBitx design paper, download the Circuits and the Software

Hackable 

  • Entire development system is on the radio and preconfigured. Start editing the code and run build to see the changes. No need for any external computer to hack this radio.
  • Written in plain C language. If you can read Arduino code, you can code the sbitx too!
  • Simple User Interface encourages you to change the layout, create you own look and feel with your own buttons, screen layouts and macros.
  • Intuitive approach to SDR
  • Understand and learn to do DSP, SDRs. The sBitx’s approach  uses a conventional superhet architecture along with convolution SDR to build the simplest SDR architecture.

The Receiver

The receiver is a hybrid architecture that filters exactly 25 KHz of RF spectrum using an aggressive crystal filter, eliminating the image problems associated with phasing type of SDRs.
  • Passive FET mixer without early amplification with +28 dBm IIP3 
  • 6 pole, 25 KHz bandwidth crystal filter front-end suppresses opposite sideband by 70 db.
  • High dynamic range IF system to preserve all closed spaced signals of digital modes. 
  • General Coverage HF reception
  • Ring free Pass Band Tuning for working CW and SSB without fatigue
  • Audio Recording of brag tapes
  • Automatic decoding of in-built modes like FT8, RTTY, PSK31
  • AGC settings of Fast, Medium and Slow
  • Band stacking VFOs, 4 frequency/modes on each band

Transmitter

The transmitter is a powerful 40 watts output radio for when the going gets tough
  • The PA uses IRFZ24N transistors that can are easily replaced even if you blow them up
  • 40 watts on 80m and 40m, goes down to 20 watts on 15m and 6 watts on 10m
  • 3 section low pass filters for clean transmit output.
  • Two VFOs with split function, incremental tuning.
  • Speech compression for SSB
  • Better than 43 dbc suppression of spurious emissions

Brief Specifications

Frequency Receive; 100 KHz to 30 MHz, Transmit: 3500-4000, 7000-7300,10000-10150, 14000-14350, 18000-18200, 21000-21450, 24800-25000, 28000-29700 (KHz)
Power Output 40 watts on 80M and 40M, 30 watts on 30M and 20M, 20 watts on 17M and 15M, 10 watts on 12M, 6 watts on 10M
Power Consumption Receive: 1.5 A Transmit : 10 A
VFOs Two VFOs A and B, with split operation, tunable in steps of 100 KHz, 10 KHz, 1 KHz, 100Hz and 10 Hz. Direct frequency entry from the keyboardRIT : Receiver incremental tuning +/- 25 KHz Split operation: Cross band
Band stacking 4 frequencies/modes on each band, selectable by repeatedly pressing the band switch.
Modes  USB, LSB, CW, CW-Reverse, RTTY(45), PSK31, FT8 (with on-display decoding and sending) 2-Tone test signal for intermodulation testing and PEP measurements.
Logging Built-in logger with N1MM format macros, Auto incremental Exchange number of contesting.
Recording Record your QSOs int WAV format files
Third party apps Fldigi: FLdigi intergrated via xml-rpc. QRZ.com: Queries your contact’s callsign on qrz.com
Receiver Noise Figure: +15 dB, IIP3 : +28 dBm
Transmitter Upto 40 watts of variable output power Better than -43 dBc suppression of spurious signals Speech compression on SSB
Telnet  Connects to RBN and DX clusters from the radio
 

Buy the Fully Assembled sBitx ($499 USD)

(Ships in 5 days)
A fully tested and working sBitx with the original 7 inch Raspberry Pi display and 2 GB Raspberry Pi, all software installed and tested. Included:
  • Fully assembled, working sBitx with preloaded software
  • 7 inch, ten touch, official Raspberry Pi  capacitive display
  • Raspberry Pi 4, 2 GB version
  • 32 GB SD card with the preloaded sBitx, Fldigi software
  • High quality, laser cut, thick aluminum enclosure
  • Large heatsink eliminates the need for noisy cooling fan 
  • Microphone
  • DC power connector

Buy the Basic sBitx ($299) (without the Raspberry Pi, the Display and the Microphone)

  • A fully tested and assembled sBitx without the Raspberry Pi, the Display and the Microphone that you will have to supply.
  • All the mounting screws, etc. required to mount the Raspberry Pi and the Display (see the Assembly Manual).
  • A 32 GB SD card loaded with the sBitx (to be plugged into the Raspberry Pi)