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
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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...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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