1940 Thordarson AM/CW Transmitter

Continuing Story of a 1940 Thordarson AM/CW Transmitter


In May, 2004 Vance sent his Thordarson transmitter home with Niel, W0VLZ. Niel paired Thor* with a National NC101X for a 1940 vintage station. He's since used this rig in the fall AWA OT CW contest and the February 2005 Classic Exchange.

This particular Thordarson transmitter was originally built without the bandswitching option. A band change required cutting AC power, pulling the rig away from the wall to gain assess via the back, carefully changing out the buffer/doubler coil and the final coil and moving the transmitter back into place. Niel found that he had the correct coil turret in his junque box along with an acceptable rotary switch for the buffer/doubler stage. Thor is now band switchable to any three HF bands.

One side effect of this upgrade was the need for an external antenna coupler. Thor, as Niel received it, had variable link coupling. Once the final coil was changed out, the link/coupling could be adjusted for maximum output. The turret mounted final coils are all fixed coupling. Niel had to add an external pi network between Thor and his 50 ohm antenna system.

Read more about Vance's ham radio stations on his web page.

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* Thor was the Norse god of thunder. He was usually portrayed as large and powerful with eyes of lighting. The Norse also believed that lightning flashed whenever he threw his hammer. Thordarson, large, powerful, lightning flashes when hammer thrown: yeap, "Thor" sounds like an excellent name.