1940 Two-Tube Two-Band Receiver

1940FebPM75 years ago, Popular Mechanics, February 1940, carried the plans for this simple two-tube, two-band receiver, which could be run off flashlight batteries, 8 for the B+, and one for the filaments. It used two Type 49 tubes, and tuned both the broadcast band and short wave. The short wave band covered the then-police freuencies, as well as the 160 and 80 meter ham bands. It was mounted on a wooden chassis and had a wooden front panel.  It was a very simple design, with one tube serving as the regenerative detector, and the second as audio amplifier.

This particular receiver would be difficult to duplicate, since the coils are unobtanium. The article notes that the coil is a “three-circuit tuner” which did away with “tedious coil winding, often a stumbling block for beginners.” The coil came with a pre-marked terminal strip which made wiring errors next to impossible. The rotating tickler coil was included. It even had a built-in switch wired to the taps on the coil for easy switching from broadcast to short wave.

As was often the case, the Popular Mechanics project was available in kit form from Allied Radio. The 1941 catalog shows this kit as selling for $4.70, plus $1.39 for the tubes and batteries.

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