Jump to content
Sign in to follow this  
AA5KD

uBITX 10-80 meter QRP General Coverage HF Tranceiver

Recommended Posts

I just bought this radio kit. The main board comes pre-assembled. You just have to wire the controls.

Technical Specifications

The µBITX is an understandable radio and, hence, can also be a learning experience. The complexity is kept to a minimum so you can always repair and make changes if you so desire.

The µBITX has a carefully thought-out operator interface. The tuning knob features many menu options available with a simple push on the tuning knob. From RIT, to dual VFOs, to the keyer, and many other features are all accessible from the tuning knob by simply pushing on it. There are intelligent defaults everywhere (these are easily overridden). Example : below 10 MHz, it auto-selects LSB and vice versa. To operate CW, you just press the morse key.

Architecture The µBITX uses upconversion to the first IF of 45 MHz. This eliminates the need for a large number of band pass filters, keeping the design simple and virtually image free. The roofing filter at 45 MHz is 15 KHz wide. The signal is then down-converted to 12 MHz where a low ripple SSB filter with 8 crystals is used to provide a sparkling audio.

The transmitter has push-pull PA using two IRF510s for a clean output. The low cost IRF510s are simple and inexpensive to replace should the need ever arise.

Receiver :

  • Sensitivity: a 0.2uv signal is clearly audible
  • Selectivity: 2.4 KHz,  low ripple SSB filter with 8 crystals
  • RIT (Receiver Incremental Tuning)
  • Continuous coverage from 500 KHz to 30 MHz
  • Sideband selection
  • Detent-less encoder tuning. Tunes with larger step rates when tuned quickly

Transmitter

  • More than 10 watts up to 10 MHz, 7 watts up to 21 MHz, 2 watts on 28 MHz
  • CW transmit with the built-in keyer
  • Uses IRF510s  x 2 as PA and  2N3904 x 4 drivers in push-pull mode for low distortion transmission.

Raduino Features

The Raduino is a small board with an Si5351 clock generator, an Arduino Nano and a 16×2 LCD display.  It plugs into the main radio board. The software that controls the radio is written in Arduino’s C langauge.

The feature set of the µBITX is controlled by the Raduino’s Open Source software. Open Source allows you to further enhance the software if you choose to do so. The menus are accessible by pushing the button on the tuning encoder. You can add more features by modifying the Open Source code.

  • Dual VFOs
  • RIT
  • Manual override of LSB/USB selection
  • CW Keyer Speed and tone selection

 

Can I build it?

Boxing it. You can pack the µBITX in anything from a cookie box to custom-made 19 inch rack. A metal box is highly recommended. We have used it every way including the bareboard on the bench.

Some soldering is required. The kit is easily put-together. You have to mount the board inside an enclosure of your choice, screw in the connectors and solder the wired connectors to the sockets and controls. That’s all. All SMD’s and other components are pre-soldered on the PCB at the factory.

Take a few hours to wire it up.  Preparing the enclosure will take most of your time. You will need basic kit-building tools like soldering iron, a VOM. etc. Set aside a few hours to wire it all up and enjoy the experience.

Support is here. Being an Open Source project, support is provided through a very active builders’ community at http://groups.io/g/bitx20. The collective wisdom of thousands of builders is at your disposal. Ashhar Farhan, the designer of µBITX is very active on the group.

What’s included

  1. A fully test and tuned µBITX HF transceiver board (6″ by 5-1/2″).
  2. The Raduino board with display with µBITX firmware installed.
  3. Detent-free tuning encoder with push button for menu access
  4. 3 audio sockets for the mic, earphones, and keyer
  5. A high quality BNC Antenna connector
  6. Power supply connector and jack
  7. 8 brass standoffs with nuts and bolts for mounting the board(s).
  8. Reverse protection diode, some resistors for CW keyer.
  9. Electret mic and a miniature push button for Push-toTalk
  10. Volume control with on/off switch

You will have to supply your own enclosure, power supply, microphone case, speaker to complete the radio.

I will continue to post through the build.

 

ubitx_all_components.jpg

Share this post


Link to post

Duane - is the xcvr finished yet?  I was looking on the web about it and wondered what your experience is if you finished it

 

Doug

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

Welcome to the OCAPA Website! Use of our website constitutes your agreement to our Terms of Use, Privacy Policy, and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.