remote control

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
remote control - schematic

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...

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