Has the California Highway Patrol been using dirtbox spy equipment to eavesdrop on proteseters?

http://www.northcountrypublicradio.org/news/npr/365073310/bill-limiting-nsa-surveillance-practices-fails-in-senate

According to the reporting, the CHP sent undercover officers to demonstrations Wednesday night "because CHP's aircraft was unable to follow the crowd due to bad weather." What kind of information were officers looking for, that the aerial surveillance couldn't supply because of bad weather?

The officers followed the protesters in an unmarked car as they marched from Berkeley into Oakland, listening for information about targeting freeways, and relayed that information to the CHP, allowing uniformed officers to prevent blockages at Highway 24 and Interstate 880, Browne said.