Sunday, January 8, 2017

BITX40 Fun

Some of us have just purchased the BITX40 SSB 40m transceiver from . This is a kind of revolutionary radio, not just because you get a working 40m SSB transceiver for $59 US, but also because it permits those hams who are afraid of building a kit transceiver from a bag of parts a chance to "roll their own". What you get for your money is an assembled and tested transceiver board, with all the various parts needed to mount it in a box of your choosing and get it on the air.

The BITX40 that I purchased did not include the digital display and digital VFO as it is now sold (mine was $49 US). The versions sold now cover the entire 40m band and let the buyer add or modify to his liking.


Because mine didn't include the Arduino controlled DDS/display board, I am adding an AD9850 DDS and Arduino Nano clone which will use the software from AD7C. In the above two pictures, you can see the temporary course and fine tune pots sticking out the side. These will be removed once the digital VFO is working. They even included an electret microphone element which I have put into a small plastic box with a PTT button.
My first BITX40 to BITX40 QSO was with Tom VE3THR, the radios sounded very good except that the analog tuning had a lot of drift. The new version solves the drifting problem with the digital VFO.
Power output is about 7W peak or more when connected to a 13.8V power supply, but the design allows you to up the voltage to the PA to as much as 25V which will give you about 20W output (of course you will need to use a larger heat sink). Check BITX Hacks for ideas on modifying your BITX40. The Yahoo BITX20 Group covering this transceiver has moved to "" at . There is also a Facebook group called "Bitx40v3 40m radio kit".

The answers to many questions that prospective or new owners of the BITX40 may have can be found on the "Unofficial BITX40 FAQ" page at  

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