Seventy years ago this month, the British magazine Practical Wireless (November 1945) carried the plans for this miniature one-tube receiver only slightly larger than a matchbox.

The tube called for by this set is a type XL triode, manufactured by Hivac Ltd. of Harrow-on-the-Hill, starting in 1935. It measures 62 x 16 mm, with a 1.5 volt filament, and the article called for a B+ voltage of 24-30 volts, although it noted that a higher voltage resulted in better performance. (This means, of course, that the batteries would be much larger than the radio itself.)

The exact replacement tube is probably unobtanium, but a suitable substitute could probably be found. You can find some discussion of the tube at this link.

The author notes that the set could tune both long and medium wave (with band switching accomplished by shorting two connections on the front panel). He noted that three or four stations could be picked up during the day, with numerous stations from the Continent coming in at night.

The cabinet shown here was made of 1/16 inch plywood. To save space, the coil was wound on a form that slipped over the tube. The variable capacitors were a dual trimmer capacitor, with the adjusting screw replaced by a metal rod with an insulated end to serve as the knob. To further save space, the set had no on-off switch. Instead, to turn the set off, the filament battery was merely disconnected. An external antenna was necessary, and the author reported good results with a 15 foot wire. A ground connection was not absolutely required, but the author did report better results when using a skewer for a ground connection when using the receiver outside.

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