This kind of circuit allowed the Radio Amateurs in the 20's to use the first triodes for transmitting. I consider it extremely fascinating because it is the kind of circuit that needs the least amount of components to transmit. On Radiotelegraphy.
With components a bit less old than those used in the 20's, and with voltages stabilization, it is possible to achieve a reasonable Radiotelegraphy quality. Both tone and frequency could be reasonably stable up to 7 MHz band.
In my case, I use oversized components. Unneeded for the power level I'm about to achieve: a few Watts. The tube is a RK-34 / 2C34, a VHF double triode used in WW II radio equipment. Differently than the 20's practice, I chose to have a rigid metal chassis instead of a wooden table, and a coil made with solid Copper instead of Copper tubing. These are the pieces I have in my boxes ... and these I will use to see if it is still possible to get some Watts out.
I have some ideas on the reason for using thick Copper tubes in such circuits, but I'm pretty convinced that it shouldn't be that necessary. I'll see and I'll keep posted.
Radioman, July 2016
Posted by Radioman | Permanent Link