1967 One Tube CW Transmitter


Fifty years ago, the March 1967 issue of Electronics Illustrated carried the plans for this simple 40 meter CW transmitter. The set ran directly off AC power, with a transformer supplying 120 volts B+, rectified through two silicon diodes, as well as 6 volts for the filament of the single 6AQ5A tube. It ran 15 watts input power, with output of about six watts.

The author, James B. White, W5LET, noted that the transmitter would be a good first rig for the Novice, as a perfect second rig for the oldtimer, or tucked away on the corner of the operating table for use as a standby transmitter.

The parts count was kept down by omitting a variable capacitor for tuning the plate circuit to resonance. Instead, the tube’s plate-to-cathode capacitance was tuned against the plate coil, which was adjusted with a slug-tuned core. A neon lamp was used as the RF indicator to assist with the tuning process and to visually monitor sending.

The rig got out, and the author reported that his first CQ from Louisiana was answered immediately from the Midwest. During its first hour on the air, the author worked both coasts.


Leave a Reply

Your email address will not be published. Required fields are marked *