DIY: Cardboard Tube Radio Kit
By James Grahame
Matias E. writes, "I found an item from Germany which I think might be of interest. It's a battery driven shortwave tube radio kit which can be assembled in just a couple of hours. I have built one and it works surprisingly well, even with an antenna of just 5 meters length (usually not really enough), I was able to receive broadcasts [in Finland - Ed.] from as far as China, India and the Middle East in good quality.
The kit costs about 49 euros (I found mine for a bit less) and it contains all necessary parts (except batteries) including chassis (made of laminated cardboard, remotely looking like wood) to build the radio. The receiver part of the radio uses a 6J1 tube, which is an equivalent of the European EF95, but for the amplifier section, they have used an IC instead of a tube, which of course some purists might consider to be a compromise, but otherwise an output transformer would have been necessary and it also might have been difficult to get the radio to run solely on batteries, 4 AA cells to heat the filament and an additional 9V battery in series to create an anode voltage of 15 Volts."
Get Your hands on a Franzis tube radio [instructions available in Dutch and German]