At certain times of the year I migrate a bit North of Southampton to an area where the the hams on VHF are grumbly and seem to be few and far between. Add to this that the local repeater only uses tone burst and that the QTH is right next to some noisy power-lines, which makes getting further afield difficult and HF deafening, and my time playing
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radio takes a nose dive. My solution to increase my air time was to take advantage of one of the perks of having a full license - remote control using, any method of communication, to control a radio in the Southampton QTH. At the start of this project I had a spare HP T5720 "thin client" lying about. These are low-power (~1-2A at 12V), small computers which have a 1GHz AMD CPU, 512MB RAM, 512MB/1GB of IDE-based Flash storage and run XP Embedded and can be picked up for very little money. The flash can be replaced with a 2. 5" hard drive with a bit of hacking and full XP can then be installed. The system has serial and parallel ports, 10/100 LAN, audio in and out, 6 USB ports, VGA, PS2 connections and a PCI slot. The first step was to decide which rig to use. My first thoughts were to use a Tait T500 which had been thrown my way by G0WFQ however this turned out to be a red herring as the audio in and out of it was atrocious so I settled for my Baofeng UV-3R. For those of you not familiar with this amazing little radio, it is a 2W 2m/70cm handheld which you can pick up for £30 or less on a well known auction site and this project prompted me to buy a second one. They are so low power that it is possible to power one solely from a USB port and there are cables available to do just that. The headset jack is a 4-pole 3. 5mm affair with fairly standard pin out (of tip to ring) Speaker, Mic, PTT and Ground. With the rig chosen I...
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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