Have you ever wanted to try your hand at building a CW rig using vacuum tubes? Well put it off no longer! Here is a neat little CW circuit which has been used for decades as a Novice Hams first transmitter. This circuit was published in the mid 1930's by Pacific Radio Publishing Co. in The Radio Handbook for Amateurs and Experimenters by Frank C. Jones. This book is still available today from Lindsay Publications Inc. and is a must have, in my opinion, for anyone interested in vintage radio construction. In his book, Frank used a single type 53 or 6A6 dual triode vacuum tube. Many Hams since have used a wide range of dual triodes or even two single triodes in this simple push-pull configuration.
Shown below are some images of one such transmitter that I put together using a small 6J6 dual triode. The 6J6 offers small construction options and requires only 150vdc for the plate voltage. The power supply for this little rig was constructed using a 1:1 isolation transformer for the plate and a small 6.3 volt filament transformer from Radio Shack. I have found 6J6 tubes for as little as $0.25 each at hamfests and due to the low crystal current in this circuit, the small readilly available HC49/U size crystals may be used. The note produced by this rig is mellow and has little or no chirp.

Front view with a FT-243 crystal plugged in. The 1/4" jack to the right of the crystal is for the strait key.

Top view showing parts placement.

Top view showing size comparison with my strait key.

* WARNING * WARNING * WARNING * WARNING * Lethal voltages are present on components and power connections. If you are not experienced working on or around high voltage equipment or electronic components, please seek a qualified person to help you. This project may not be suitable as a first electronics project and you must be a properly licensed amateur radio operator in order to operate this transmitter. If you choose to build this project or one similar, you do so by your own choice and at your own risk!

Circuit Data L1 - 31 turns of 22 guage enamled copper wire close wound on a 1.9" PVC form. L2 - 2 turns of 14 guage enamled copper wire loose wound over the center of L1. B+ - 150 - 160 VDC Plate Current - 24 ma Output Power - ~2 watts (Depends on emission strength of the tube.)

Back to WV7G's home