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Tips and Tricks for the Bitx SSB transceiver

The Bitx is a low cost easily built SSB transceiver designed by Ashar Farhan VU2ESE. One of the most popular homebrew designs, version of it are in use around the world.

Here's the original circuit that started it all. Note that it was for 14 MHz, designed to allow Indian hams their first taste of DX. It was then put onto 7 MHz as this is easier than 14 MHz for QRP, even if the maximum distances obtained are often not so great.

There are two main versions of the Bitx. The first had a free-running VFO. This was often unstable and numerous fixes to improve its stability were developed. These range from modifying the existing VFO to converting it to a more stable ceramic resonator to adding an external DDS. Such modifications are of historical interest only as the later (and current) version features a stable DDS VFO. My comments below relate to the earlier non-DDS model.

If you want one, just head over to HF Signals page and order one. You'll be glad you did - it's one of the best values in amateur radio today. You get a pre-assembled and pre-aligned board with off-board sockets, controls and microphone. You need to find a suitable box for it and do about an hour's worth of soldering. After that you get a good performing portable HF transceiver capable of contacts up to about 3000km or more.

Featuring a Bitx to Bitx contact, this video demonstrates what they sound like on the air and the results possible.

The videos below document my experiences with the Bitx, starting off with a 'from scratch' version built before kits came out. As I have the pre-DDS version I spend some time with frequency control, adding a ceramic resonator VFO for better frequency stability and then a DDS VFO. As the current Bitx comes with a DDS VFO these videos aren't relevant. However I do recommend you watch the ones to do with transmitter audio and other modification.

My first Bitx

Review of the HF Sigs Bitx (older non DDS version)

Repairing a friend's Bitx

Micro sized microphone for the Bitx

Improved audio from the Bitx by varying the carrier oscillator

Making the Bitx more stable (ceramic resonator mod for non DDS Bitx)

Adding the OzQRP CDV DDS VFO to the Bitx (addition for non DDS Bitx)

Removing DDS generated noise from a QRP transceiver (potentially relevant to the Bitx)

Audio AGC for the Bitx - Part 1

Audio AGC for the Bitx - Part 2

Audio AGC for the Bitx - Part 3 (signal strength meter)

How good a Bitx can receive at an RF quiet location

What to do if the Bitx's power isn't quite enough to get through!


Visit the Bitx 20 email list/forum to read about others' experiences with all different versions of the Bitx (and uBitx). You can also join and ask a question.

You can slso post your query on the main uBitx Facebook groups at BITX40 and uBITX QRP Radio Kit.

Next steps

As a result of assembling your Bitx you may find yourself hooked on simple rigs. If you want multiple bands the uBitx is the logical choice. Or if QRP and portable operating has won you over then further information on these is contained in my Minimum QRP and Hand-carried QRP antennas books. These are available in both electronic and paperback form (some countries).



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