HF Transceiver

I would like to describe so far the most complicated project on this site: multiband SSB transceiver, that covers 0.1 - 30MHz. The design procedure was started in June 2007 and it hasn't ended yet. During this period of time, I changed the main concept many times, because the ways I had followed were finally wrong. I will be adding the descriptions of each module of the transceiver when it's complete and well tested.

General characteristics of the device:

• full coverage 0.1-30MHz
• first mixer chip AD831 - theoretical IP3 at 20dBm
• intermediate frequency - 9MHz, OMIG PP9/A2 quartz filter used - polish version of well-known KVG XF9B, IF amplifier - MC1350, product detector - MC1496
• synthesis on the AD9854 DDS
• control board powered by microcontroller ATmega32
• encoder made of a stepper motor
• memory bank
• USB interface
• galvanic isolation: audio output and USB port
• output power: doesn't known yet

Because of an thread on the one of the polish electronics forums I decided to include much more information about the radio frequency design and elements. Fairly it was my first contact with the RF technics, so I will describe the problems I had to deal with. They are highlighted green. The extraordinary RF components descriptions are coloured pink.

Now only one module is tested and completed - audio board, but in the near future I'll add more of them

Audio board

An description of the module, that contains low frequency bandpass filters, audio amplifier and BFO oscillator.