ok, muchisimas gracias.no sabia que hubiera un sistema como este en onda larga. gracias por vuestra ayuda, e encontrado la web http://www.datatrak.ws/services_datanetworks.asp <http://www.datatrak.ws/services_datanetworks.asp>que habla del tema nuevamente gracias
2009/6/18 Claudio Periolo <[email protected]> > > > Es Datarack. > > Datatrak is a medium-area LF automatic vehicle location (AVL) system > operating in the UK, Benelux countries, Germany and Austria. It is operated > by Securicor Information Systems in the UK and by Siemens-Datatrak in > mainland Europe. It was originally developed to fulfil a need for the > monitoring of Securicor's own parcel and security vehicles, however it is > now marketed to a number of other customers. The system is a conventional > hyperbolic positioning system where a number of stations making up a chain > transmit in sequence on a common pair of frequencies in the band 130 to 170 > kHz. The receiver calculates it's position and communicates this back to the > control centre (Swindon in the UK) by means of a UHF radio system that > provides similar coverage to the LF network. The system is enhanced by the > provision of Event Activated Tracking (EAT) or 'Trak Bak' as Securicor call > the product. This allows a stolen vehicle to be tracked and aprehended. > Also, the UHF component may monitor various inputs from the vehicle, > providing a telemetry function. > > There are apparently 14 sites in the UK but their location is unknown. The > sequential transmissions are clearly audible at around 145 kHz in the UK, > the interesting thing about them is that they 'warble' as if FSK modulated > at around 20bps. Using Manchester coding, the transmission would still be > usable for positioning as long as the phase were averaged over many symbols. > > > Buscando en listas los vas a encontrar de donde son, si los encuentro lo > envio. 73's > Claudio > > > --- El *jue 18-jun-09, juan jose <[email protected]>* escribió: > > > De: juan jose <[email protected]> > Asunto: [ondalarga] sabeis que es esto? [2 Attachments] > A: [email protected] > Fecha: jueves, 18 junio, 2009, 7:23 am > > hola, escuchando por la onda larga me e encontrado con esto, sabeis que > es? > es en 133,78 y 147,04 khz > > saludos > > > ------------------------------ > > ¡Obtén la mejor experiencia en la web! > Descarga gratis el nuevo Internet Explorer 8 > http://downloads.yahoo.com/ieak8/?l=e1 > > >
