A Regenerative Receiver with AGC for 80 Meters or 3-10 MHz Shortwave

  
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Here`s a Regenerative Receiver project that I designed for the 80 meter Amateur band, but which can also be used in a wider-tuning configuration that covers approximately 3 MHz to 10 MHz, for Shortwave (World Band) listeners. Built in the same style as my previous `40-Meter Tweeter` which can also be found at my Radio Projects menu at, this radi
A Regenerative Receiver with AGC for 80 Meters or 3-10 MHz Shortwave - schematic

o features: * 3-10 MHz tuning set by pc board trim capacitor, but main panel bandspread via varactor diode tuning which is renamed Main Tuning and covers a band of frequencies variable to 150 KHz from where the pc board trimmer is set * Low input impedance matches 50 ohm antenna system - giving relatively little AM overload/bleedthrough (although you may want to add a 3. 8 MHz bandpass filter after the antenna jack and input diodes; see text and schematic below). This is version 1 of this design, so it is to be expected that there will be some modifications, especially as I get feedback from other builders who try the circuit out for themselves. Other features that I will probably include in the next version of this basic 80 M regen are: * I may add a zener diode regulator - So far, the 80 M prototype drifts in frequency very slightly; not nearly as much as the 40 meter version did, which absolutely required a zener regulator * A built-in audio amplifier and speaker. Right now there is a headphone jack, which I am running into a Radio Shack amplified speaker (they still have `em! Get `em while they`re hot and not-yet-discontinued! $12. 99 last I checked) * An S-Meter circuit. I actually designed one with the AGC included in this radio, but had some problems with the "zeroing" of the meter tending to drift off zero after a while - so I left it out of this first version and plan to include it in the next, when the bugs are...



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