Results are shown on an analog VSWR meter. The design was originally published in `Break-In`, New Zealand`s amateur radio magazine in Sept/Oct 2005, and is republished here with the permission of the editor. Note: `Break-In` is a term used in amateur radio to describe a system which allows another person`s signal to be heard in the brief
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intervals between transmitted Morse Code symbols. Like many hams, I`ve been playing with antennas for years. Much of that experimentation has been, in hindsight, somewhat hit and miss, relying mainly on SWR meters and grid dip meters. When I built an RF noise bridge (See Reference 1 - Note: All references are found at the bottom of this page), the resulting impedance measurements were a major advance, but it required a full coverage receiver and considerable analysis with a programmable calculator or PC before useful information was obtained. Recent attempts to build a compact multi-band HF antenna required more careful measurements of antenna impedance. I briefly considered buying one of those commercial antenna analysers frequently advertised these days. Glancing at the cost, I innocently thought Just how hard would it be to build something like that Casting wisdom to the winds, and with a little free time out from my regular jobthis, and a subsequent digital antenna analyser (described here ), were produced. An antenna analyzer is a device which measures the impedance of an antenna. The first, described in this article, is an all-analog device, with not a microprocessor in sight. The second, described elsewhere on this website, is a fully fledged digital meter complete with LCD display. Both cover the full 3 30 MHz HF range. The analog analyzer, as you`ll see from the photograph, is quite small. Powered with a...
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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