APRS, the Automated Packet Reporting System is a mystery to many — hams and “civilians” alike — and continues to be to me as well.  It is often used for community events such as marathons and I thought this set of tracks from the 2010 Austin Marathon was interesting:

APRS tracks at the 2010 Austin Marathon

You can see several APRS units having been tracked here. This view was captured about 1pm with a 6 hour window looking backwards so what you see is virtually the entire APRS support for the marathon. I’m not sure what the AMDOWN-1 tracker was, but I’m suspecting it was a mobile digipeater to give better access into the APRS-IS system, i.e. feed the tracks into the internet.

These type events are done as a public service and also to drill the skills that may be needed for emergency communications.