Reinartz Receiver (Homebrew Design)
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| Frequency | RX: ~200-28 m (HF/shortwave, roughly 1.5-10.7 MHz) |
| Bands | ~200m-28m (HF/shortwave) |
| Power | Receiver only |
| Modes | AM, CW |
| Weight | 2 kg (4.4 lb) |
| Connector | binding-posts |
| Year | 1921 |
| antenna | binding-posts |
Estimated (unverified): Weight varies (each example is hand-built); ~2 kg is nominal. Coverage and exact circuit vary by build; the original 1921 tuner spanned roughly 200 to 28 meters.
John L. Reinartz published this regenerative receiver design in QST in June 1921, and it became one of the most widely built amateur receivers of the 1920s. Its key advantage was smooth control: the tuning and regeneration adjustments interacted very little, which made it easier to operate than many earlier regenerative sets. Buildable from readily available parts, it gave good results on CW and covered an unusually wide range for the day, from about 200 meters down to 28 meters.
As a regenerative receiver it can radiate back into the antenna and cause interference, and it takes skill to tune right up to the threshold of oscillation without squealing. Selectivity is modest and most builds are headphone-only. Because each was hand-built, no two are exactly alike.
Reinartz published his tuner in QST for the whole amateur community to build, and thousands did - an early example of the homebrew tradition of sharing a design for others to replicate that continues today. It is a landmark regenerative receiver that shaped homebrew radio history, valued more as a piece of that history than as a practical modern receiver.
The Reinartz receiver is a celebrated regenerative receiver design from the early 1920s, named for the American radio amateur John L. Reinartz, who refined the regenerative circuit into a particularly effective and popular form and published it as 'A Receiving Tuner for C.W.' in QST in June 1921. Like all regenerative receivers it works by feeding a controlled amount of the detector's amplified output back to its input - regeneration - which sharply increases sensitivity and selectivity, letting a single tube pull in distant and weak signals far better than a simple detector could. The original tuner covered an unusually wide range for its day, from about 200 meters down to 28 meters.
Reinartz's arrangement of the tuning and feedback (or 'tickler') controls gave smooth, stable regeneration with very little interaction between the two adjustments, which made it easier to manage than many earlier designs; in 1922 he simplified it further onto a single coil form with switched taps. It became a favorite homebrew receiver for shortwave listening and amateur reception during radio's explosive growth in the 1920s. Operating it is an art: the listener brings the circuit just to the threshold of oscillation for maximum sensitivity.
As a landmark regenerative design, the Reinartz receiver occupies a permanent place in homebrew radio history. It is a historical and homebrew design. Compare it with the crystal set and the National SW-3.