Goodman Band Imaging Receiver

  
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By taking advantage of certain characteristics of superhet action not normally used, it is possible with one pair of coils to cover both the 80- and 40-meter ham bands as well as ranges where commercial point-to-point c. w. and shortwave broadcast signals may be found. ”Donald H. Mix, W1TS, `A Beginner`s Four-Tube Superhet Receiver, ` QST, March 19
Goodman Band Imaging Receiver - schematic

50 CE Minimizing reception at the image frequency is fundamental to useful practical application of the superheterodyne principle ”unless the image happens to lie in another amateur radio band, and you want to receive it. This page explores the band-imaging receiver topology popularized in the 1950s by Don Mix, W1TS, and Byron Goodman, W1DX ”a design approach that uses a single local-oscillator tuning span to receive either of two bands without oscillator-tank switching, each band the image of the other. We see its pre-echo in George Grammer, "A Two-Tube Superhet, " QST, February 1941 CE, pages 12 15 and 92: In a simple regenerative-detector-behind-a-mixer receiver with a 1. 6-MHz intermediate frequency (IF), the same plug-in oscillator coil is used to tune the ranges 5. 4 10. 0 and 9. 5 14. 5 MHz. Wrote Grammer: It will be noted that the same oscillator coil, D, is used for two frequency ranges. This is possible because the oscillator signal is placed on the low-frequency side of the signal on the higher range. This not only avoids winding a second coil, but also gives somewhat greater stability at the highest-frequency range. . . . A word about images. The receiver will, of course, respond to signals either 1600 kc. higher or 1600 kc. lower than the oscillator frequency. The unwanted response, or image, is discriminated against by the tuning of the r. f. circuit. On the three lower-frequency ranges, when it is possible to...



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