The material in this section shows how we built the Twist-Shift system for VHF using commonly available (and cheap) surplus land mobile VHF transceivers modified to operate on the 2-meter ham band. The radios we used were the 100-watt Motorola SyntorX model. The radios were additionally modified for the Twist-Shift experiments as described below.
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This section also describes the auxiliary circuitry needed to implement the system and the test setup for the experiments we ran to prove that the concept works and to quantify just how well it works. This page describes the VHF Twist-Shift Keying setup using the SyntorX radios. The material is presented, not as a hard and fast specification of equipment and circuitry, but as an example of how Twist-Shift can be implemented. A method for driving the transmitting antenna elements `in quadrature`, that is, with two precisely synchronized sources of RF energy offset in phase by 90 degrees. A dual synchronized receiving system that provides separate paths for the orthogonal signals picked off from the receiving antenna. Synchronization requires that injection sources for all mixers in the system be driven from a common source. The receiving system must also be "normalized", that is, the two signal paths must be brought back into zero-degree phase synchronicity. The cross-polarized antennas we used for feasability testing are shown here. They consist simply of two j-pole type elements cut for a resonant frequency of 146 MHz mounted orthogonally. The transmit antenna was suspended from the rafters of an outbuilding on my property 50 meters distant from my shop where an identical receive antenna was likewise suspended from the ceiling. Calculated path loss from the transmit end to the receive end was 50 dB. Later, the j-pole...
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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