Shown here, from the February 1945 issue of Radio Craft, is a compact one-tube shortwave set dubbed “The Ultra.” It’s a superregenerative set covering 10-120 meters using a 117ZP7-GT tube. One half of the tube is the rectifier, with the other half serving as the superregenerative detector. The magazine notes that the set features post-war details such as phosphorescent panel marks. These are made from glow-in-the-dark paper coated with calcium sulphide which is carefully applied to the panel. After being exposed to the light, the markings will then glow in the dark with a purple hue.

The set is shown here with a bent antenna, and the author notes that this antenna is sufficient for strong stations. He cautions against use of an outdoor antenna, as the set will radiate and interfere with other nearby receivers. He suggests the use of one stage of RF amplification if an outdoor antenna is used.

One shortcoming of a superregenerative receiver is that it’s practically impossible to listen to code. When the key is down, the receiver is silent, and when the key is up, the receiver is making a loud rushing noise. Since this is the exact opposite of how it should sound, the author acknowledges that this is a shortcoming. But for AM signals, it would appear that this little set would really pull in the stations.