Very Low Frequency (VLF) radio signals and earth currents, and probably even fewer could really care about it. However, there are those who have a serious interest in such things, and actively persue the monitoring and recording of the effects, whilst theorising on how they might be caused, so at least I can rest reasonably reassured that I`m not completely alone here! My knowledge and experience of natural VLF
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phenomena is rather limited, but I enjoy the opportunity to set up my home made detection equipment somewhere away from built up areas and to just sit and listen to the variety of sounds, waiting for that really unusual one to come along. A bit like fishing perhaps. I first became interested in these natural VLF signals when I accidentally stumbled across them whilst conducting experiments in earth current communication, after reading about it in an old magazine, probably Practical Wireless. The article mentioned how bases were set up during the First World War for communication between the trenches, and I found the technique used very interesting - to the point of attempting it myself. Without going into too much detail, a signal is fed into the ground via two earth stakes set some 25 metres or so apart, and the signal can be received some distance away by using another pair of electrodes and some amplification. As it happened, I didn`t manage to get much distance during my tests - perhaps a couple of hundred yards - partly due to a high level of mains hum and other noise masking the quiet signals, but it did give me the chance to hear for the first time the sound of atmospherics which I almost instantly decided to investigate at the expense of any further trials in earth current signalling. Are you aware that very low frequency radio waves, way below the reach of normal radio receivers and so low that they fall into our...
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....
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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....
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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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