Homebrew with tubes

During our 2009 Fielddays, I’ve built a hartley ECO CW transmitter, using an EL84 tube.

I then got inspired by the Glowbug from SM5GNN, The re-introduction of the “Mighty Midget” and the article “one hour transmitters from G3VA TT september 1988. I decided to build a new “One Tube, Two stage, Three band CW transmitter. Project name AM “Amazing Midget”

it’s a 5W Crystal-controlled transmitter based on a single triode-pentode valve (eg ECL82 ECL84, ECL85 or ECL86)

With a ECL86 it should be able to provide some 6W output. (Tnx Jacob, PD0JHM fer ur support)

To be honest, I started this project already on the 30th of september 2009. (and found it back this weekend)

Important part is the homebrew, air-wound tank-coil. (Method, see Electron may 2009) See picture below:

Recently, the 5th of december 2010, I’ve modified my 2009 EZ80 tube power supply to have a negative 150V bias.

After collecting some more Junkbox components the story continuous on December 24th 2011. Preparing the aluminium chassis, drilling the holes…It would be great to show it on our “openday” December 29th ……

To be updated soon

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