Thursday, 4 February 2010

Taxi Data

A lot of taxi firms are now using data for their dispatching. The main frequencies for this are between 163 and 165 MHz. I found a little (97KB!) program to decode this data. It's a Java application so should run on most OSs. It decoded 2 different sorts of taxi data but there are some which it doesn't recognise.
Also I tried Trunkview which is an MPT1327 trunking decoder program for Windows. As well as in Band 3, there are quite a few trunked radio systems in the UHF bands round here. Trunked systems are annoying when scanning because of the continuous data channels but these data channels could also be used as propagation beacons because they are usually in good locations and transmit 24/7. The ones in the 440 MHz band are good for 70cm propagation and there are 2 of these in the West Midlands on 440.800 and 442.9125 MHz which appear whenever there are lift conditions on 70cm. There are also the data transmissions between 440.0125 and 440.4875, which are 24/7 (the 'click click click' sounds) which are in good locations but not as useful as they reuse channels more closely. 440.100 is from the centre of Preston and the best 'beacon' for this area.
Is XP just as bad for synchronising the clock as Vista? According to Windows, it synchronised with when starting up at 9:10pm. 10 minutes later, the time error was so bad that WSPR would not work at all. Using About Time, the time was corrected by 9 seconds (also using
Downloaded and tried Shutdown Monster, which can shut down the computer at a certain time, after a countdown, when CPU use drops etc. Could be useful for when I want to go out and leave the PC on for a while but not all day.

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