Superheterodyne receivers have been mass-produced since around 1924, but for reasons of cost did not become successful until the 1930s. Before the second world war other, simpler receiver technologies ...

This article is intended to introduce the beginner to the interesting and challenging art of high frequency radio design. It is also intended to entice the seasoned professional to take a deeper look ...

If you’ve ever built a crystal radio, there’s something magical about being able to pull voices and music from far away out of thin air. If you haven’t built one, maybe you should while there’s still ...

Marked: "Day-Fan Electric Company / Dayton, Ohio / Serial No. 089 / Type No. 5056". Unit is Tuned Radio Frequency receiver in a mahogany finish cabinet. Five Kellogg 401-A tubes are employed in a ...

Marked: "Oriole Jr. / Trinum Circuit". On plate: ORIOLE Receiver / Model 90 / Serial 402 / Warning: Trinum Circuit Used in this receiver is patented and infringement will be prosecuted / W-K Electric ...