We truly desire we had a bit more info on the building of this, however [Jeff] made this APRS tracker a number of years ago. APRS, or Automatic packet Reporting System is a system where shortwave radios put out little packets of data that are uploaded to a database offered via the web. This specific one is relaying GPS data so his household can see where they are located. With present phones, you may believe this is antiquated, however he notes that he took this with new Mexico as well as was able to transmit his setting even when there was zero cell phone coverage.